What comes first the chicken or the egg, Body filler or primer?

[Durant Mike]

I have not done much painting on cars, except small pieces that have not required much body work or preparation and most of that was done by can. I'm about to paint my fellows and hubs, and have ordered all the supplies, I have the safety equipment and everything I need. I have had the fellows and hubs bead blasted and they are looking fine. There is a few rust pits left in the metal after blasting, not many maybe a couple that will need to be filled with some filler. They are not that deep but will stand out with the new paint. I guess my question is this. Do I put an epoxy primer on the metal first, then fill with evercoat or allmetal or do I put the filler right on the bare metal, sand and then coat with epoxy primer. Also can you use a polyester high build primer over the epoxy primer. Don't want to make myself more work than needed.

[trimacar]

Epoxy primer first. Body filler and regular primer both allow moisture to get to metal, epoxy primer won't. The ideal situation is to prime immediately after blasting, at that point the surface is perfectly "wettable". A blasted metal surface will begin rusting immediately from the moisture in the air, even if you can't see it.....

[Restorer32]

PPG DP90 sealer over bare metal then all filler and rough sanding, then PPG K36 primer, more sanding, polyester filler for minor surface imperfections then maybe a second coat of K36, final sand, then DP 90 again and apply paint. Be careful to pay close attention to the "open" times on the various products. I think DP 90 can be topcoated within 72 hours. If you wait longer than 72 hours you will need to scuff or lightly sand the surface before applying topcoats.

[Durant Mike]

Thanks Dave & Restorer32. Just wanted to get the answer from the experts. Hope to start on them next week. I've had the blasted parts inside the house for a week, no signs of rust, but will clean them up real good before I shoot them.

[nickelroadster]

Before you start priming, you need to metal prep the metal. Even if you have had the parts inside, they are most likely to have begun rusting on a microscopic level. If you insert this step and then follow restorer32s instructions, you will be in good shape. Metal prepping is an easy step that should not be skipped.

[Durant Mike]

I have some Ospho and was going to wipe down the parts first with that, prior to priming.

[DavidMc]

I have always applied any plastic filler to the bare metal then applied the primer because the instructions for the filler say it must be applied to rough sanded bare metal and that is what I was taught when I did a basic panel beating/spray painting course many years ago.

I just checked the web site for the plastic filler to see if this has changed and I asked the supplier, both say apply over bare metal.

Is this a new development - plastic filler over the primed surface? I am not familiar with the product names referred to by Restorer32 but similar products will no doubt be available here in Australia. I need to know more about this because obviously the faster you can coat the bare metal the better.

[nickelroadster]

In the old days, filler was always applied over bare metal. Body filler has an affinity for water so it was applied as far from the surface as possible. With the common use of epoxy primers which is waterproof it makes more sense to prime first then apply filler over the top where the body filler, which may attract water, is not touching the metal. The older primers were only water resistant would eventually let moisture in. By priming both before and after application of body filler, the filler is isolated from metal (which it could cause to rust if any moisture reached it) and the outside elements. Many paint jobs in the old days eventually failed from the older types of primer transmitting moisture, especially if painted on a humid day.

[Coley]

An added note for sandblasted metal.

You should also scuff sand blasted metal as small metal spurs are made during the blasting process.

Scuff sand these off, metal prep and then epoxy prime for the best base for refinishing.

[DavidMc]

I continue to learn on this site, however I need to research local plastic fillers because I am still faced with a modern product with a spec sheet saying it is applied to bare metal. I need the one that is applied over the 2 pack primer. I assume you scuff the primer to improve the bond of the filler.

Also another step in the painting process after metal prep and before the first coat is a wipe down with wax & grease remover. I also use a tack rag between coats to remove any traces of dust.

[61polara]

The key word in everything said above is EPOXY primer. The spec sheets for epoxy primer state that body filler can be applied over the primer and it will hold. If you are not using epoxy primer, the filler should be applied to bare metal. When applying filler over epoxy primer, you must scuff the shine off the primer with a grey scuff pad or the filler will not hold.

[Durant Mike]

Thanks everyone, your suggestions is really helping. I hope to start on this this upcoming week and I want to do things right. I have all the supplies except sandpaper, but I'll get that on Monday.

[nickelroadster]

The old style body filler is still basically the same with as previous poster says, epoxy primer. I have seen several different instructions for sanding the primer before the filler. Different products have suggested from 80 grit sandpaper to scuff pads to prep for filler. Obviously if you are using 80grit, you want to have a fair thickness of primer to work with. Which ever way you go, make sure the surface has some tooth to it.

[Guest wombvette]

When applying filler over epoxy primer, you must scuff the shine off the primer with a grey scuff pad or the filler will not hold.

That would be only after the critical set up period, which for epoxy could be from a day to a week depending on temperature conditions. I always apply it before that period is reached.

[Guest martylum]

I would take a different approach here and first apply epoxy primer to scuffed bare metal and wood, then apply 3-4 coats of a catalyzed sandable primer after the time specified with your particular epoxy primer (usually about an hour). No sanding needed tween the epoxy and the sandable primer. After proper cure time on the sandable primer depending upon the temperature, cut it away with 80 grit and then deal with any remaining pits in the hubs and rims with more fill primer or plastic if needed.. Minimum temp. for spraying should be 65 or, even better, 70 degrees.

Do be careful about film buildup where the rims meet the wheel. Too much buildup can make a very tight fit.

In my shop plastic goes over the epoxy primer.

Martin Lum

[Coley]

When I was doing a lot of small bare metal parts everyday, I would fill a spray gun with epoxy primer and use it the first day, then put it in the refrigerator over night and use it again the next day.

It would keep for up to 3 days and then I would clean out the gun and refill.

If it got a little thick on the 3rd day, just add a small amount of lacquer thinner and keep going.

Never had it fail and I quaranteed my work for 1 year on every job.

[Durant Mike]

Hey everyone thanks for all your pointers. I'm pretty heavy into my restoration, but this is the first time painting parts that I want to come out looking great. Bigger parts such as fenders, splash aprons body etc I'll probably have a shop do since I really don't have the space to paint these. I'm trying to do the wheels, axles, frame and all the running gear myself to save $. Wiping down the parts with Ospho today, hope to start the primer tomorrow or Thursday. I'll let you all know how it went.

[mrpushbutton]

I learned to put filler over Epoxy primer, and totally agree with this method as described by my esteemed collegues here. I look at putting plastic filler on bare metal as a recipe for trouble, and an outmoded way of thinking. The biggest idea here is adhesion of the filler to the host, and rust is your enemy, like the man said, the rust you can't see. One thing about body work: It is like Italian cooking--ask 5 experts with impeccible track records "the one absolutely right way" to do something and you will get 5 different answers, each one absolutely correct in their view. In this case the judges are more in favor of filler over EPOXY primer, which makes them OK in my book!

[danhar1960]

I am about to apply some primer to the body of my '39 and this all answers a lot of my questions.

I do have one question though rising from the original post, what are "the fellows" ??

Danny

[DavidMc]

Danhar1960. I think Durant28 was referring to "feloes" which are the wooden rims set inside the steel rim on a veteran car. Not on you '39 Buick. I see you are in Sydney, I use VG Auto at Girraween for my paint supplies, their prices are good and they offer excellent advice for the DIY including free Saturday classes. Highly recommended if they are anywhere near where you live.<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <w:DontGrowAutofit/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--> VG Auto Paints

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[danhar1960]

Good info Dave. Thanks for that and I keep that mob in mind.

Danny