Paint and refinishing

​I'm a Professional automotive refinisher by trade and I'm willing to offer advice and pointers to anyone who is going to refinish their own vehicle. Pictures are most helpful but I cannot give exact estimates without looking at the car in person. I can offer advice on materials to buy, tooling to use and the best kinds of paint, primer and sealer to use as well as proper repair and painting procedures for a quality DIY paint job you can be proud of. I'm also very knowledgeable on metal finishing and replacement, welding techniques, chrome repair on stainless (dent repair) and custom painting techniques (stripes, scallops, flames, airbrushing, wood grain, marbleizing, cob webbing, dry brushing, aging techniques, etc) I can also offer advice on chopping, channeling, frenching lights and antennas etc.

Today, I'm going to talk about metal finishing techniques. There are several methods to remove dings, dents and damage from a metal panel. I use a few methods to achieve a smooth defect free panel, One method I use on large damage areas is a stud welder to pull the areas back flush with the surrounding panel area. These are great inventions because they help to shrink the metal to avoid oil canning and are great for areas that you can't reach the back of to hammer and dolly. One word of warning though they heat the area up cherry red for just a second so fire prevention is your friend. Remove any flammable items away from the backside of the panel. Sometimes on older thicker steel cars though these don't have the oomph to move the metal the way you need and a better method is needed for those types of cars. I've used the drill and screw in dent pullers before and they work good but you have to weld the screw holes up when you're done. I'm not a big fan of those style, but if you can't reach the backside of the panel sometimes there's no choice if the stud welder isn't working.

When I first started painting cars I watched a man from Jamaica repair a quarter panel on a 1968 Chevelle that had been in an accident. He was supposed to replace the panel but I guess he didn't get that shop memo and repaired it instead. The damage was pretty severe and he proceeded to yank and pull the panel to straighten and rough it out which is nothing special, then he grabbed a metal body file (the kind used for shaving high spots on old thick metal cars and the same kind for doing lead repair). He used this metal file and an array of dollies and started slapping the quarter back into shape a little at a time. See the thing about using this style is that the file shrinks the metal as the dolly helps to smooth it out so you never get the dreaded oil can effect. I was a young man at the time and had never been taught this technique before and so you can understand my amazement at how well it seemed to work. I watched him work on this quarter for a couple of hours and the quarter was really taking shape! By the time he was done for the day all that quarter needed was a skim coat of body filler a quick sand and ready for primer. The thing is when I talked with him, in Jamaica you can't get new body panels like you can in America so you have no choice but to become great at metal finishing (or become a total hack! lol). From that point on I used that technique whenever I could and with practice I started to get the hang of it and I have to say it works very well.

Hammer choice is important because too big and you're doing more damage then you're fixing and too small and you'll be there for a month of Sunday's trying to move the world with a tooth pick. When I'm using a hammer and dolly I use my shrinking hammer the most. A shrinking hammer has a waffle pattern on the striking surface that helps shrink the metal as you're banging it back into shape. They help to stop the oil can effect when repairing damage, much like the metal file does. I use the shrinking hammer to move the panel and then I switch to the file to finish smoothing it out. This method seems to work great and I use it often. The goal is to use the least amount of body filler (bondo) as possible, less is better and if you don't need any that's even better.

The art of the hammer and dolly technique that I use is when I'm using the shrinking hammer I hit the high spots and keep the dolly on the low spots and not necessarily right behind the hammer. I move the dolly around as well as the hammer. I start out using this technique until I get the main bit of the dent out then I switch to the file and dolly. I move the dolly behind the file and begin slapping the metal to knock down the high spots and bring the low spots up flush.

Metal finishing is time consuming but when you're working on a classic car that is next to impossible to find new sheet metal for it can be a great skill to master. Nothing is better then the satisfaction you get from taking a panel that some would cut off and replace and making it look almost new again.

Cheers!

Mark

Thank you. A lot of us here are into saving precious sheet metal our selfs. Others just write checks. I own and work on my 1939 Packard and 1938 Lincoln Zephyr which panels are rare tho not near as much as many cars on this forum.

This is great! Please tell us more!

You guys are welcome! I've learned a lot from forums over the years and don't mind helping someone out with info I have and they may need.

I'm going to add to my previous post a bit.

Sometimes it's necessary to use heat to help remove damage from a panel. This is helpful because it helps to stop any splitting of work hardened metal. Work hardening happens when for example you bend a wire coat hanger, the bend spot is harder to straighten back out once it's bent. If you continue to bend that same spot back and forth it will eventually break because you're basically cold tempering that part of the wire hanger. I've had metal split on me and you have to stop weld the split and now it's very hard to fix that damaged area as well as you could have before you welded it, not fun but it does happen if you're in the heat of the moment (no pun intended lol).

Heating a damaged spot that has hard creases or crinkles in the metal will help relax the metal and make it easier to smooth those spots out. This works very well on hard creases and gives a great finished product within a quick amount of time versus cold hammer and dolly work.

One word of warning though, fire prevention is your friend. if the panel has any undercoating or something flammable behind it, it can and will start burning in short order. If you can get behind the panel a touch of heat and a wire brush will remove any coatings from the back very easily. If you can't get back there sometimes a little shot of compressed air will put a flame out and do this in an area with lots of fresh air because it will get very smokey very quickly. Water in a squirt bottle works well too but will harden the metal like quenching a sword after forging it.

The torch method works well on panels with a hard body line or a panel that was stamped with undulating curves all converging in one area. Those panels will already have a bit of work hardening done to them and then add the damage and you can do the math on how long it will take before you're welding up a split. Heating up to a dull red works very well, no need to go much hotter then that. The heated spot will rise or grow a touch from the heat but with hammering and shrinking as it cools it shouldn't cause any major worrying.

Be very careful though, heating the panel up will make the metal very malleable and you can move it a lot and take a chance of stretching it too much. Which will add to your work and not be of much help. A little at a time and lots of patience is the best method so you don't overshoot your goal of a straight panel.

Heating an area and quenching it with a wet rag will also help remove any oil canning spots. It helps temper and shrink the area just a touch. Alternating heat and a wet rag will help to fix even the most stubborn spots. Moving the torch to different areas of the damage help to tune the spot into shape as well. This method will not however shrink the metal enough to remove the stretch out of a spot. You'll have to use a shrinking hammer and or file and a dolly to get rid of that.

The great thing about metal is that you never truly screw it up. Alternating between hot and cold hammering coupled with patience and you can fix just about anything.

The kind of heat sources I've used are of course oxy/ acetylene torches, propane torches, mapp gas torches and even industrial heat guns but only on thinner modern steel has that worked for me and only with limited success.

If there's any tips or hints you guys are looking for in particular ask away! the only dumb question is one that's never asked and I take requests.

Cheers!

Well, today seems like a good body filler talk kind of day.

I've talked about metal finishing techniques a bit, so I figure body filler is a nice new topic to cover.

Okay, you've metal finished as far as you feel you can take a damaged area. It's not as perfect as you'd like but you feel pretty good about it.

If it needs a bit of body filler then mix up a batch without using too much hardener and spread it on. I mix mine by taking the hardener and for a tennis ball size batch and put about a two inch stripe of hardener right on top. Make sure you mix it thoroughly, you don't want any color stripes in the filler because it won't fully cure in spots. Make sure you spread the filler past the damaged area onto the surrounding good area and make sure the damaged area gets a good hit with a grinder or roughed up really good so the body filler has something to bite into. 24-36 grit grinder discs are your best bet and wouldn't go any finer than 80 grit for a good bite and grind or sand into and past the repair area. Long spreader strokes give you the best results here. If there is any chance the body filler could be exposed to moisture and there is no possible way to weld the hole/s up, you should use duraglass, tiger hair or some sort of fiberglass body filler as your first coat. It's water proof unlike standard body filler is. Standard body filler has a lot of talc in it and will absorb moisture from either the air, rain or even when you wash your car and can cause the panel to start to rust from the inside out. If there's any doubt use fiberglass filler first then go from there. The steps I've listed work for that type of filler and you can spread regular body filler over the top of it after it's properly block sanded.

The reason for this is that if you put body filler on just the damaged area, sand it, prime and paint the panel, you will still see the damaged area. Because although you filled the low spot you didn't level it off with the surrounding area. Okay you've spread your filler past the damaged area and given it ample time to cure. One thing I do is I rough block the area with 36 grit file paper before the filler is completely cured, it takes a bit of a learning curve to know exactly when that window opens up for you but it cuts down on block sanding time once you figure out when your window is. It mostly boils down to how much hardener you mixed your filler with and the size and depth of your repair area as well as ambient temperature. I do it when the filler is just barely tacky and you barely leave finger prints on it. If you touch it and your finger still goes into the filler a bit, wait it's not time yet.

Your body filler has cured enough and you're ready to start blocking the area, start with 36-40 grit sand paper and the longest block you have that is appropriate for the area you're fixing. If it's a roof, hood, door, quarter panel or decklid (trunk), the longer the block the better your results will be. I start blocking in a crisscross pattern, changing direction often. I block past my repaired area at least by half the blocks length to get the area nice and flat. One word on block types though, you can use air files and big orbital sanders (bondo busters) but if you're new to body work it's very easy to take off more material then you should with them and cause yourself more work and more filler than you need to repair the area. I recommend hand blocking the area to start and get the feel for the work, it's not a race and you want it to look nice the first go around.

Once you've got the area sanded nicely, place your hand on the panel palm and fingers flat and rub past the repaired area back and forth, (go a little slow you aren't trying to start a fire) go all the way to one side then back to the other. You're doing this to find high and low spots that you can't see. Really try to get level with the repair area like you're shooting a game of pool. A guide coat works well here too. I use the cheapest lacquer black spray paint you can buy and just mist the whole repair area. You don't need to cover it in paint just splatter it on and it will show you where the low spots are and where your high spots are when you go back over it with your sanding block. Make sure you scuff up any filler spots that didn't get sanded with sand paper to give the next coat of filler something to bite into.

Word of warning though, do not use rustoleum or rustoleum type paints for this or anything you will be painting with automotive grade primers, sealers or paints. It's an oil based enamel and does not react well to solvent based paints. Lacquer based is best for this application or any that will be painted with automotive grade paint at a later time.

When you feel you're at the guide coat stage, change your sandpaper grit over to 80-150 grit, it not only continues to smooth out the repair but also helps you feel where the high and low spots are and gets you one step closer to the primer stage. Once you have your repair area nice and flat use compressed air and blow it off really good. The reason is you're looking for pin holes and other defects that occur when you use body filler, I use evercoat smoothing putty. It's a two part ultra smooth sanding body filler that is great for filling pin holes, sanding scratches and other defects. Make sure when you see those defects and pin holes you really try to push the putty into them and fill them in. It can ruin a paint job if any are left and you will see them plain as day on a painted surface. Again make sure you spread the putty across the entire repair area all the way to the good surrounding areas. I generally sand with 150-220 grit sand paper at this stage, it gives an ultra smooth surface for primer and helps you feel any high and low spots you may have missed when you run your hand back and forth on the repaired area. Once I've sanded my first coat of putty I used compressed air and blow it off good again to catch any left over or missed pin holes and defects. I use a single edged razor blade to fill any that I find once I get to the this stage. It doesn't have to be a new blade but just can't have any oil or grease on it and I use it just like a body filler spreader. Sand those spots lightly with a block to smooth them out when it cures. Remember putty is for very minor imperfections, if you still feel or see with guide coat major low spots or high spots putty will not help you yet. Putty is very viscous and is not meant to be a heavy or deep imperfection filler but more for minor pin holes and the filling of heavy sand scratches like the 36-150 grit kind and any left over grinder marks that may have gotten missed.

By sanding with 150-220 grit sand paper you are getting the repaired area smooth enough so the primer is working to fill very very minor low spots and not working overtime to fill deep sand scratches. The primer when fully cured will shrink just a touch and you will see every sand scratch that is rougher than 150-220 grit. Not what you want when you've worked so hard getting the area looking nice. Primer is for very fine defects and sand scratches and not meant to fill heavy waves or low spots, if you're still feeling any waves or high spots you weren't done with the body filler and blocking yet and should not prime the spot until those areas are nice and smooth and flat with no low spots or heavy grit sanding scratches and grinder marks. You won't see them right away but if you use primer to fill them they will show up when the primer fully cures and you won't be happy with it as well as you will see the wavy spot where the repair is.

I've used a few different styles of blocks over the years. Hard rubber blocks work well but only go up to a certain length and on large repair areas they are too small. There are file boards for the larger repairs and finally there are semi rigid foam blocks and they come in all sorts of different shapes and sizes. I love my foam blocks and prefer those over anything else in my arsenal of sanding blocks. They are great for gentle curves and give enough flex but maintain enough rigidity to get an area nice and straight. They can be a bit costly but in my opinion they are very worth the price you pay.

There are a few companies that make the foam blocks so shop around and find the best price to quality that you can find them for. Getting them in a set of all different shapes and sizes will probably get you the best deal.

Cheers!

Thanks for the tips.

What is involved in chopping a top? On some cars it looks great. I realize that new glass has to be fabricated, etc. I am more curious on the accurate removal of metal - how does one figure out the amount to remove? Cardboard templates? Or ??

Teach away, please.

Thanks,

Tom

Hi Tom,

That's a complicated job but one that can look really cool if done correctly and definitely not for the faint of heart to take on.

You can chop a roof as low as you want really but the lower you go the harder it is to see out of the car. Most people will go between 2-4" for a chop that is still functional to drive without a lot of sight issues. Some fabricators have chopped the front a touch more then the back roof pillars to give the car a more aggressive look but I wouldn't over do it because it can quickly look bad and not in a good way. Lol

A lot of fabricators will chop the middle and rear pillars and lay the front pillar (windshield frame) back to get the look but still have an easy time getting replacement windshields in the future. They also can drop the front windshield frame down lower in the front cowl as well as lay the frame back but this only works on certain styles of cars. There are instances where this doesn't look right such as the 20's-30's era cars they need a full chop in my opinion.

With windows flat glass in the older cars is great for chopping because with a simple cardboard template you can get glass cut at any local glass shop, just make sure it's safety glass. Most shops can do that without too much difficulty. There are some glass shops that can cut front windshield safety glass but you may have to shop around to find a place that can do that.

Now the elephant in the room, how much to take out? Depending on your particular car a safe number would be between 2-4" at the pillars. I know still vague but that's generally the norm. I use cardboard for templates for extra pieces you will need to fabricate to fill gaps because when you chop the pillars they usually have larger base then at the top. Sometimes you can use the parts of the pillars you've cut out if there's special hard to fab lines or stamped areas that could be a real pain to try and hammer out on sheet metal yourself. Poster board works good too and easy to work with for small pieces.

Depending on the car the roof won't fit your new opening when you cut the pillars. It will be too small, you will have to section your roof panel into quarters and then add sheet metal to fill the gaps you will create to get the pillars to line up correctly. You will have to use some metal rods and a tape measure to get your roof level and lined up to weld your roof sections back together again.

I've also seen fabricators lay the back glass frame down instead of cutting the opening and piecing it together. Which gives you the lower roof line you're looking for but still makes it easy to replace the rear window if it ever breaks and you still have good visibility out of the window as well.

Measure, measure, measure and measure again before you even touch a saw blade or die grinder disc and start cutting. It's easier to erase a bad measurement then to try and weld where you shouldn't have cut.

I use masking tape to mark my measured sections on each pillar to mark my cut lines. I measure both sides of each pillar, put a mark with a good marker and put the tape as straight as possible between those two marks.

When you cut the pillar try to keep your cuts as straight as possible to aid you in fitting the top back on.

Also, you will need to use some steel rod or the like to tie the car together before you cut the roof off. This keeps all your gaps intact and helps the car retain its current shape as it would be with a roof on it. Just imagine the nightmare if you cut the roof off, weld the chopped roof back on only to find that your car body relaxed on you and nothing fits right. Most fabricators will weld rods in a crisscrossing pattern tying the four corners together and then weld rods running from the front of the car to the back and on the inside of the door openings to help the car keep its shape. Even if the car is sitting on a full frame I would still do that step before you make a single cut. I always feel like it's better to over do the steel rods then to try to do the minimum.

When you've made your cuts and you are welding the roof back on you will run into spots where you feel like you can just weld up a small space instead of cutting a strip of sheet metal to fit the spot.

I would avoid that and make the sheet metal piece that would fit because you will have to cut down any and all trim pieces that fit those areas and it's much easier to drill fresh trim holes in sheet metal as opposed to a heavy weld spot.

When it comes to fitting your top back on you will most likely have to make some vertical relief cuts and remove some sheet metal to get things to line up again. With most 20's-30's era cars try to make all your cuts in the middle of your pillars. This makes it easier to line them up when you're ready to start welding. I only remove roof pillar material from one side such as just from the roof panel that way I feel like it helps keep everything more uniform. An example is if you're doing a 4" chop you would only take 4 inches of pillar from the roof side and not 2 inches from each end of the pillar. With later model cars you may have to split your cuts between the two halves of the car because you will have less fabricating to do in order to get the two halves to line up. It all depends on the car style really, straight pillars on a model t would be easier then a 1951 Mercury would be. The straight pillars I would take from just one side and the curved and sculpted pillars of later body style cars I would do a 50/50 split. That's how I've done them before and it works pretty good.

You may run into window openings that will need some attention for them to look like they should again. If it has a sweeping arc you wouldn't want an abrupt hard corner or hard line where there wasn't one before, so you will have to fabricate a nice sweeping curve that fits the lines of the opening.

If you are serious about doing this on you're own car I highly suggest looking for video tutorials on YouTube and or buying a book that can help walk you through the process. That way you can get a visual of just how it's done and get a better idea of the amount of work it takes to make it look like it was supposed to be like that from the factory as it should when you're done.

Although not an exhaustive list of things to do, it should give you a good idea of the direction to go if you want to do this to your car.

Chopped cars can look really good if done properly.

I hope this helped shed some light on the process for you Tom.

Cheers!

Mark,

What is a good book on the subject?

I believe a chopped roof looks cool on the 42 - 48 Buicks.

I do not like to cut up an unmolested original, but would rather do a modified car from 20 other donor cars without guilt.

Tom

Tom,

I can't say for sure what book would be a good one to get. I would check the library near you, you may get lucky and find a good one. I would suggest possibly getting a few from different authors and take all the info as good advice. What one fabricator does another may say it's not the correct way or simply just against his way of doing it.

There are so many versions of the same story so to speak. The way I mentioned was the way I was taught as well as tough lessons I learned on my own.

I would check online for a good book or two on that and read the reviews of what people are saying about the book. That would give you a good idea what they thought of the info.

There may even be other fabricators who chime in and tell how they felt about the info as well.

My guess is you'll have to buy a book or two since I think it wouldn't be the type of book kept in a library but can't hurt to try.

If you find one post a link here and I can give it a once over and tell you my thoughts on it.

Cheers!

Thanks Mark.

If we can keep you going - what is involved in "Frenching" and channeling?

Hi Tom,

Sure no problem, happy to offer up my knowledge to help other's out.

I'll start with frenching, when you do that it's generally mentioned with headlights and or taillights and sometimes with radio antennas. I'll start with antennas because that's the easiest to do.

The easiest and coolest way I've done them is first choose a cool antenna, generally a power antenna looks the coolest in my opinion but I've seen stationary ones that look cool too.

Measure the base of the antenna mast nut, which is what attaches the antenna to the body of the car. Once you have that measurement you can either find a steel washer that you can bolt that antenna to or fabricate a round fairly heavy gauge bit of sheet metal that will fit the antenna. It has to have some rigidity to it since a power antenna has a bit of torque to it when it goes up an down. Okay so you have the new mount for your antenna and next you need to find a tube of some sort to mount that washer or round sheet metal base to. The easiest way to find a perfectly round tube is conduit, or some galvanized steel pipe works too. I'd lean towards thin pipe as opposed to heavy gauge pipe, kind of the same as heavy sheet metal (that's why steel conduit works well). If you can find steel pipe that isn't galvanized that's better but it's okay if it is or if you can roll sheet metal into a tube that works too.

Next you have to decide how deep you want the antenna to sink into it's new home. Most often just past flush with the body of the car is the norm when the antenna is down and the car radio is turned off, but you can go a bit deeper if you'd like. Just know that the deeper you go the harder it will be to get paint into the tube. Now once you have the length or depth of your tube measured out you'll want to use a hole saw that is the same size or a touch bigger then your pipe, the same size will generally give you a nice tight fit. Locate on the car where you'd like your new antenna to be and drill your hole. You'll have to measure how tall the antenna mast is when it's in the down position then add an inch or two to the length of tube and cut it. You can go with less extra length but in case you put it on the car and decide you want to go a touch deeper you can without cutting a new piece. With your new antenna tube you can take your washer or round steel mounting base and weld that to the tube and then slide the tube into the hole, if you don't smooth the weld out you'll have to do that from inside the car.

Adjust the tube for the depth you want and tack weld it in place making sure it's nice and straight and level. You don't want it going up and down crooked. I just grind the left over length of tube down until it's flush with the panel once I finish welding it on fully. Take care to weld and cool a little at a time because too much heat in a small area can cause a panel to warp from the expansion of welding it. Finish it up with a skim coat of filler or you can add custom body lines to the hole area if you'd like. I've even seen them have multiple frenched antennas and they each raise to a different height.

French headlights and taillights generally is taking the chrome beauty rings that are common on older cars from the 40's-50's and molding them to fit the front or rear fenders to give them a nice smooth fit and transition from the fender to the headlight or taillight. Basically you find a chrome beauty ring from another type or model of car (50's era fords were common to use for 50's era chevy's) and then attach them to the car and smooth the transition between the two pieces out so you almost don't see any chrome except right around the headlight or taillight itself or a very small strip of chrome. Some old school guys would use lead body filler to smooth the transition out between the two pieces so you really have to look to see where one stops and the next starts. That's the traditional hotrod way to do it.

I've also done them by deleting the big chrome ring and welding sheet metal around the openings of the headlights and elongating the opening or lip of the headlight or taillight opening just a touch for a real custom look and just using the beauty ring that holds the headlight bulb in the socket. Sometimes depending on the car model you will have to use headlight buckets and beauty rings from a newer model car for this method. This way gives the illusion that the headlight or taillight is sunk into the fender with a smooth lip all the way around it.

Channeling a car is a bit more labor intensive kind of like chopping a roof. Channeling first became popular in the 50's when hotrodders would buy a 20-30's era car and take the body that sits on top of the frame, cut the floor along the frame rails and lower the body down to almost cover or fully cover the frame. Then you weld new sheet metal on the floor and box that part of it around the frame drill holes and mount the body in it's new position. This was a major custom touch in the 50's but one you could do to your car in a weekend or two.

Now there are a few methods to channeling a car, One way is the way I mentioned and another way is to take the car and actually cut the sides and take a section out and weld it back together. Usually the amount you take out is an inch or two. This method is also called sectioning a car but it basically does the same thing by lowering the height of the roof relative to the ground. This is a major project but if pulled off correctly can look very cool and custom.

To channel/section a car you would generally take metal from the lower middle part of the body. Measure and remeasure to insure you cut both sides the same as well as the doors need to be sectioned so measure them for a proper fit and finish. For the doors I would peel the doorskin flange on the inside edge away from the inner door frame. but not too much because you need to reuse the skin so just get it to release from the door frame without causing to much damage to the outside of the skin. Make your cut on the door frame and and put the new sectioned bottom piece back on line it up and weld it back to the door frame. You'll have to trim the bottom of the doorskin because it will be an inch or two too long now but leave enough so you can fold the lip back over the shortened door frame to give a factory appearance to the inside door frame.

The rest of the car you will basically be cutting the car and removing sections of sheetmetal and welding it back together and smoothing it all out to give it a factory like streamlined appearance. you'll have to do some prefitting for each bolted on part such as fenders and doors as you go because even though you measured sometimes situations arise like a mounting point is now in the way of another mounting point for another body panel. Let's face it you're in custom territory now anything can happen! lol

If there are any model specific factory body lines on the lower side of the car you will most likely want to keep those and section those back in or cut around them to maintain a factory streamlined look but still get the custom touch you are looking for. Like for instance a 60's era mustang with stamped scoops on the quarter panels. You would want them to still be there when you are done because it would look strange with only one where there should be two of them.

Hope this helps shed a little light on some custom body work terms that are used in hotrod circles.

Cheers!

Thanks again, Mark!

Tom

I'm going to talk about primer and how to properly block it.

You finally have your metal finishing and or your body filler fine tuned and feeling really good. The next step is priming and blocking to further refine your prep work for painting your car.

One tip I can give is make sure all the edges of your panels are sanded nicely and any chips or bits of body filler is sanded smooth.

You need to use compressed air to get all the sanding and any body filler dust off the car and out of all the nooks and crannies. The last thing you want is dust and dirt blowing out of a jamb or channel and getting in your fresh primer. Make sure you hit all areas, even areas you don't think there will be dust like inside of fender wells and inside door jambs. Even behind fenders if attached, anywhere that dust can settle, it will.

If you are painting your door jambs and trunk/ hood jambs you'll want to get those areas prepped to prime it all at once. It gives you a much better paint job in the end but if you want to do those later I suggest masking those areas off with tape and paper so the primer isn't getting on areas that haven't been sanded or prepped because it won't stick and will cause you problems later on by peeling and flaking off those areas.

I prefer to have the body panels off the car for ease in priming the jambs and the outside all at the same time but room can quickly become an issue in smaller spaces and leaving the car together works as well. In those cases I tape and paper off the areas such as the door openings so the I can close the doors and hood but still able to open them to prime the insides and keep overspray from going inside the car interior, trunk and engine compartment where you don't want it.

When all your masking is done I use a grease and wax remover on the whole car or area being primed. I wet one rag really well with grease and wax remover and then use a dry rag to wipe it dry and try to always use the cleanest part of the rag and when all areas of the rag is dirty get new ones and keep going. I do this twice in a row. It gets all the left over fine dust and cleans any possible oils from your skin and any possible contaminants off the car and helps with that final finish you're looking for. This step also helps you find any left over pinholes or minor defects you may have missed and you can fix those with a touch of putty and a razor blade. Give those areas a light block and blow it off again and wipe it down with grease and wax remover.

Once you decide on a manufacturer for paint and primer, stick with them from beginning to end. Not all paints and primers are compatible and can have horrible reactions to each other such as "lifting" or what's called wrinkling, adhesion problems and any number of other issues. By mixing paint lines and manufacturers you take the risk of ruining an expensive and labor intensive paint job that you will have to strip off and start back at the beginning.

You're finally ready to spray your first coat of primer. I suggest mixing it exactly as instructed on the directions from the label on the can or info the paint store gives you for it. I also suggest buying those plastic mixing cups that have the mixing ratio's printed right on them. Those cups are really inexpensive, they take all the guess work out of mixing paint and primer at the correct ratios and actually helps you save money by using the proper amounts and removes the guess work out of mixing. There are also metal mix ratio sticks you can get but unless the cup you're using is a perfect cylinder and the same circumference at the top and bottom they are't as accurate and I would shy away from them.

I mix an amount equal to how much you think it will take for you to be able to spray in about an hour depending on how hot the temperature is. Primer usually starts to "kick" or harden in about 45 minutes to an hour at about 75 degrees F. I spray really fast so I mix an amount for a full spray gun and then mix another spray gun full to have waiting for me so I can theoretically get one whole coat on the car at a time. I also overlap my spray pattern by about 50-60% depending on how thick your primer is and how well your spray gun handles the material. If your spray gun has multiple fluid tips and needles you'll want to use the largest one for primer. You'll want to do nice even coats with no dry spots or major orange peel or a really rough finish. Spray all the hard to reach areas first then finish that panel off by spraying the rest of it, be mindful of potential areas that can cause runs or sags.

I will spray at least three good wet coats of primer so that I have plenty of material to block with. Right after your last coat I always dust a guide coat on it to aid in blocking and it helps you see any low spots that need fixing. I use a black lacquer spray paint or rattle can and generally the cheapest I can find. This way you can block out any very minor waves or low spots on your panels and really give yourself a nice flat base for your final finish.

When your primer is fully cured (usually about a day or so, depending on ambient temperature) you can start blocking it out. I always start with the longest block I own and do all the areas I can with it. I do my first block with 150 grit sand paper and block in a criss cross pattern, using the longest strokes I can. I try to go from end to end of the panel, if possible and any large flat panels like the hood, roof and deck lid (trunk lid) I block from the middle to the edge on panels with a center body line and ones without I try to block from one side as far as I can reach and then finish the panel off on the other side.

Blocking primer is a big step towards a really nice paint job. All your prep work will show when you do your final coat of paint. Meaning that, all your body work, primer work and final blocking is 90% of a nice paint job. Now you can see why this is an important step.

In order to get the first batch of primer blocked fully (yes, you should prime and block at least twice) just sanding it until it looks sanded isn't enough. You need to block out this first primer coat until you start seeing either metal or body filler showing through in spots. It's okay if this happens because you are further tuning in and straightening your panels out by doing this. You should see spots popping out on every panel or you aren't done blocking. Don't go too crazy though because you don't want to sand all the primer off just flatten out the panel further. One trick to see how it will look when it's painted is after it's blocked you can get a rag wet with grease and wax remover wipe it on the panel and get down and look at how the light reflects off the panel. It should start looking pretty flat and not many waves or dips. If you do see some areas that aren't flat yet then you know that spot needs a little more work to flatten it out whether it's more blocking or needs a touch of filler, now is the time to fix those spots.

Once your car is all blocked and prepped, blow it off really well with compressed air and wipe it down with grease and wax remover and a clean dry rag. Check all your masked off areas to make sure they are still sealed up and fix the areas that aren't. Mix up your next batch of primer and spray the entire car again with at least three good wet coats, waiting in between each coat for it to tack up a touch. Let this round dry for a day or so. If you are able to push or pull your car out into the sun and help bake that primer a bit it helps the primer cure better.

The next round of blocking Is wet blocking. That's if your last bit of blocking didn't show any problem areas that need another round of 150 grit dry blocking. I start out with 400 grit wet sand paper and use the biggest block I can find. I've even used rectangle shaped polyester plastic sheet cut to a decent size block for this step, as long as it's rigid and flat it will work well. I knock the primer down and then switch to 600 grit wet sand paper to finish off the primer and get the 400 grit scratches out. I continue to sand in a criss cross pattern going from body line to body line when possible. I also change direction often to avoid making and odd flat spots or causing waves in the panel.

I hope this has helped remove any mystery or questions you have about priming and blocking a car. If you have any questions don't hesitate to ask.

Cheers!

Thanks for taking the time to give us the great information.

This all goes into the "SAVE" folder for my next project.

Keep it coming.......

Bill

Awesome, many thanks!!

I've asked this question elsewhere but I want to ask you straight up. I have been usiing PPG products on my car so far. Stripped it to metal, then epoxy primer, next 2K primer. I have it to the point of ready to spray. PPG paint is 400$ a gallon and BASF is 200$ a gal. is there any reason to use the more expensive paint? Will it make any difference changing brands? I'll be spraying acrylic Urethane, pure color no metallic or pearl etc..

May I ask a question? I have a 73 GMC truck I bought new. We call the color baby s... Yellow. Had it repainted 6 yrs ago and it really gets oxidized. It sets out and is covered 50/50. Try to keep it polished, but what a bear when oxidation has started. Any tricks? The paint used was the PPG people have spoke of. Thanks!

If you had used top of the line PPG Base/clear there would be no oxidation. There is a reason cheaper paints are cheaper. You get what you pay for. PPG's "Shopline" line of paints and materials are made primarily for body shops that don't expect their customers to keep their vehicles for more than a few years. Acrylic Urethane is relatively inexpensive but doesn't hold up well over time. We painted cars 15 years ago or more with PPG Base/clear and they still look as good as when they were sprayed. There are no time nor monetary shortcuts to a good looking and long lasting paint job.

Wow, I completely restored this truck and paid good money.....kinda p..... me off. Should I have had them clear coat it, like the new paint jobs? Is that what you mean by base/clear?

You should have had them use better paint. There definitely is a difference in paints. Generally, the better the paint the more expensive it is. I have a boat we painted with the less expensive paint and it oxidizes just like your truck. Base/clear is just 1 option. It would be interesting to know exactly what product they used.

I've always used the PPG base coat/clear coat system and have had great results. Cheap paints.... not so much..

Was wondering if anyone may have insight for using Nitrocellulosis process on my 30 Dodge when I'm ready to paint ? Things to be aware of or techniques that may not be otherwise made readily available to the public in the descriptions.

Going to use Hibernia for the system in keeping with originality for my project when I get ready.

http://hiberniaautorestorers.com/nitrocellulose-automotive-laquers.php

We still use lacquer now and then. A customer insisted on ordering his own lacquer from a business in Northern New Jersey. Despite our suggestion that he order plenty of paint at the same time he ended up ordering paint 3 times and all 3 times it was a noticeably different color. The only good thing about lacquer is that you can paint a car in a barn on a windy night with a broom and still get a decent job.

Here's our cost for base/clear we used on a recent project:

1 gallon DBC base $462.80

1 gallon Urethane clear 231.65

1 quart High Solids Urethane hardener 129.45

Total 823.90

The job actually used most of 2 gallons so double that cost. We recently paid over $900 for a gallon of a pure red base. Red is always the most expensive.

Live and learn....thanks!

Live and learn....thanks!

Any suggestions for a good paint system for painting my truck. I have an older Cambell-Hausfield 2hp electric compressor. This may be OK but I believe a good air filtration filter is important. Any specific models for a filter?

I am a hobbyist restorer and any suggestions is appreciated.

Thanks for the responses. i plan on using PPG Concept DCC urethane. It's not cheap, just over $400 a gallon. The car wont be in the sun much, and garage kept, so I figure the paint will last as long as I'm around, lol.

Any suggestions for a good paint system for painting my truck. I have an older Cambell-Hausfield 2hp electric compressor. This may be OK but I believe a good air filtration filter is important. Any specific models for a filter?

I am a hobbyist restorer and any suggestions is appreciated.

Stakeside,

If it was me it would really depend on what product/reducer/thinners/amount of air (CFM) your CH will push. 2HP isn't much but it really comes down to CFM in the long run for me if your talking about "flow". Hard to answer your question with limited info. Need to know much more.... Your CH may be enough to do the job but more specifics are needed...

Due to the age of your truck, Lacquer would be correct FYI. You can go with a PPG base coat clear coat (which is an offspring of the Ditzler original line) but it won't be original to your DB truck. Nothing wrong with base coat clear coat if done right (as mentioned above) so it's really up to you as the owner to decide what you want to use.

Many different professional opinions on all of these products discussed so keep that in mind when evaluating your choice.

As for filters I always use a local top notch facility, either Banner or Fastenal for proper filtration products.

Edhd59,

I would pay the extra money and stick with the same product line. You could get lucky and it could be okay mixing products but if it doesn't mix well are you willing to put all that work at risk for $200?

You are already saving $1,000's by doing the paint job yourself. It can delaminate or peel off on you or wrinkle up or not lay down right for you.

Hope this helps!

Cheers!

Thanks Mark, I have been to other forums as well (specifically for auto painters etc) looking for comments about the two paint lines. Without asking questions, just browsing their discussions, I found many many times the same statement you made. The PPG Concept line was also stated to cover better than the others I was considering. Now if I could just get off these 12 hour days so I could get down to the paint store. Thanks again for taking the time to answer a newbies questions.

Mark,

   Great job putting all this knowledge down for this post.  Lots of people talk about 2k epoxy primer which I will use, but I live in a high humidity area - near the Texas gulf coast.  Do you use Ospho prior to 2K primer, and any recommendations on application?  This may be a very location specific issue.  Wondering what to do with the parts when they first come back from the media blaster.   Thank you,   Hugh 

Great information. Xclnt. Thank you.

How does one paint inside a tube? I have the spark plug conduit off my 1930 Dodge Brothers 8 for straightening and repainting. The tube is rectangular, about 1.5" x 1" x 20" or so. My best thought so far is a piece of foam rubber on a stick, sort of like those "speed brush" things in the DIY shops.. Thanks for your thoughts.

I need help working out what to do with my decaying paint. I have a 1951 Nash that had great paint - it looks like it had a respray a long time ago - however in the last 2 years it has started decaying really quickly. It has been outside very little - but it seems that every time it sees the sun more cracking and fading occurs. Can anyone advise a forum or specialist who could help - I am based in Honolulu. The pictures are below _ i would really appreciate some advice before it is too late. 

On ‎7‎/‎1‎/‎2016 at 10:11 AM, Hubert_25-25 said:

Mark,

   Great job putting all this knowledge down for this post.  Lots of people talk about 2k epoxy primer which I will use, but I live in a high humidity area - near the Texas gulf coast.  Do you use Ospho prior to 2K primer, and any recommendations on application?  This may be a very location specific issue.  Wondering what to do with the parts when they first come back from the media blaster.   Thank you,   Hugh 

Blow the parts off with air pressure. Wipe down  all surfaces to be painted with a good quality autobody "pre-cleaner" solvent. Even if you think it's clean. Then blow it off again.  That's in case the sand blaster  guy's compressor piston rings are worn and it is passing oil and he's not using very good oil/water  filters in the air lines. Same for your compressor blowing off the dust. Check it by blowing on  one spot on a clean sheet of white printer paper and see if the paper shows water (dries out) and/or, oil stains (doesn't dry out).  When sandblasting the oil vapor gets forced into the metal surface in a fine mist that's too small to see, but can cause paint issues later.  I have multiple filters inline before my sand blaster - both oil/water separating and large, paper element filters, but it's not worth the risk of having to re-spray after spending thousands of dollars of labor and materials on paint, just to save some bucks on a gallon of pre-cleaner and some clean rags.

As for dealing with moisture - even if it's a rainy, muggy, day.  As a sub primer I then use PPG's  DP40LF and DP401 two-part epoxy primer. It actually absorbs and uses the slight amount of moisture from the air, and/or, on the surface to help as part of it's curing process.

I used it for many years when my shop was at the damp-climate of the south shore of Long Island. Never had an issue with it. My brake/clutch riveting stand was sandblasted clean then painted with just 2 coats of DP40 and was stored outside for  5 years because of lack of shop space. That was painted 30 years ago and there's still no failuar of the primer, and neither with any of my customer's cars that I've used that DP40 on.

Paul  

Regular Dawn dish soap in a bucket of hot water with a bristle brush is an excellent metal prep.  I do this first and then I use a waterborne prep cleaner with lint free rags.  Both of these products will cause flash rust quick so you have to get on it with a waterblade/dedicated synthetic shammy and air gun to dry.  It's a hustle procedure.  

Regular solvent based preps just don't clean like the waterborne stuff.  It removes grease better but not blasting dust and such.  Try it and you'll know what I'm talking about.  

I second Fitz's PPG DP series of primers as the first step of anything after the metal is bare. Use it to protect the metal before any plastic filler is applied. Then you do not have to worry so much about plastic filler moisture getting to the metal and causing rust right from the get go or later.

I got away form using Ospho and went to DP 40 seires directly on clean metal. The Ospho process (includes water rinse) caused flash rust here in the east. Maybe in 10% humidity areas....

Yes, wash car before any work is started. Then use Wax/Grease remover on repair area first. Then start sanding. Sanding silicones and wax into the repair area is asking for fish eye trouble!

The magic number for humidity in Michigan is 50% or under won't flash quick.    Above that and you better hurry.  At least these numbers are in the shop from the humidity gauge. 

We bailed on dp40 in the mid 90's when it went lead free.  I've tried several before relying on SPI epoxy.  Best product of it's kind for me.  I use it for bare metal, build primer, and sealer before final paint.  One product for the build.

 I use the black epoxy and haven't used a satin type of finish for almost 10 years.  Epoxy is my primer and final chassis coat for the frame and all the underhood satin finish items.  

On 5/13/2017 at 2:40 AM, oska said:

I need help working out what to do with my decaying paint. I have a 1951 Nash that had great paint - it looks like it had a respray a long time ago - however in the last 2 years it has started decaying really quickly. It has been outside very little - but it seems that every time it sees the sun more cracking and fading occurs. Can anyone advise a forum or specialist who could help - I am based in Honolulu. The pictures are below _ i would really appreciate some advice before it is too late. 

It is already too late. Nothing short of a repaint will repair your deteriorated paint.

OK, I looked at SPI epoxy primer spec sheet, and I do not see where it is good for a build primer. Sounds just like the old DP epoxy from PPG.

Did you have failures with DPLF?

Back when we used the old dp40 with K200(I think as it was 20 years ago) for a 2k build primer.  Good combination that held up well.  I've stripped cars my grandfather did in the early 80's with DP40 and it held up great.   Occasionally we would hit three coats of dp40 for build instead of spraying one coat and then going over that with 2k fill primer.  The nice thing about original dp40 was it's sanded decent.  Once dp40LF came along it was no longer sandable and would gum the paper.  We dropped it their and searched for a replacement.  

Using epoxy for build seems to stop any shrinkage the 2k's filles seem to do.  It's a much slower cure product so it won't work for everybody.   When I'm rotating parts through the process I have time to let a part sit a few weeks on the extreme end.  It doesn't build as much per coat as your shooting from a 1.5 tip.  3 coats of epoxy does a decent job of filling.  The procedure is not for everyone as it takes longer but it does a great job and It's nice to know you have one product for the foundation of the paint.   I don't do all epoxy for every job but most of them are.  

Take a look at the SPI forum.  It's one of the best paint related forums out there.  The core guys are truely experts and not internet experts either.   I've used SPI for over ten years now and I've never had a problem.   All of their products are the highest quality or right their with the others.   Limited colors so I use Standox or PPG solvent base with SPI clear.   I have guys thinking I'm trying to save a buck with generic products but this stuff is better and the price is better.   The difference is a PPG shop gets all the perks from their mega contracts or sponsoring race cars while guys like me have to eat the price hikes.   The tech line is second to none as you talk with the owner of the company who still paints.   He almost always picks right up and if he doesn't he'll call back with an hour.  Good luck getting this service from Xalta or PPG.