RoadsterRich Posted February 20, 2003 Share Posted February 20, 2003 I recently purchased a small abbrasive blast cabinet from a well known inexpensive tool distributor (Initials: HF). Since acquiring it I've checked the local book stores and a few online stores for books on media blasting in general. I've come up with few of them and have no clue what would or would not be a good one.Where is a good place to start learning about using the cabinet?It came with 4 nozzles: 4-1/2mm, 5mm, 6mm and 7mm. It requires 5SCFM at 80-125PSI. I purchased some 80 Grit glass bead media (it was what they had on hand in the store). I have boxes of bits ranging from wheels to small steel plates to stamped metal bits. Where do I get started learning?How does the pressure affect the process? How do you determine the size of the nozzle to use? How do you select which media to use for what?Okay I know it is a long winded vague question, but pointers for beginners would be greatly appreciated.Thanks,RichPS: The Roadster would really like to have some of its bits cleaned, primed, painted and ready to be installed. It is getting impatient with me! <img src="http://www.aaca.org/ubbthreads/images/graemlins/grin.gif" alt="" /> Link to comment Share on other sites More sharing options...
ronbarn Posted February 20, 2003 Share Posted February 20, 2003 Rich, first let's deal with the pressure. Using glass beads, keep the pressure low, about 40 psi, max 50 psi. At high pressure those little beads hit the metal and shatter, becoming dust and basically unusable. A bead blasting afficianato may spout linquistically about different grits and media for specific types of blasting. I prefer the simpler life. I use medium grit beads from WW Grainger for all around blasting. Sure it may be slower for some applications, but keeping only one type of media makes life easier. If it is cutting too fast, lower the pressure and back away from the target. If it is cutting too slow, get in closer. Clean off any obvious significant dirt, grease, rubber, etc. covering the target. These act to absorb the beads and/or bounce off the beads with no cutting action. DO NOT USE THE BLASTER IN LIEU OF SOME INITIAL CLEANING!!Be sure to have a good filter and even better, get a TIP catalog and set you your air supply with a good water trap, filter and air pressure guage that you can see from the position of standing in front of the blaster with your arms through the holes.You will find a couple of things - One, this will become one of your best friends in the shop; Two, You learn best by doing. If you wait to find the definitive book, you will have wasted a lot of time just using it and getting good work done. I predict, however, that after a few months you will be wanting to find a little more space to move up to a larger TIP (or similar brand) unit. <img src="http://www.aaca.org/ubbthreads/images/graemlins/cool.gif" alt="" />Oh yes, forget to address tips. Smaller ones for narrower blast area and vice versa. I have gone to just one size tip for all work (keep life simple). When it wears to too large a diameter to be effective, replace it. Outside of the common tools (wrenches, hammers, screwdrivers, etc.) this is one of the most used tools in my shop. I hate to work with dirty components. Of yes, one more item, avoid using the blaster on bearings and some electrical components. Link to comment Share on other sites More sharing options...
Guest DeSoto Frank Posted February 20, 2003 Share Posted February 20, 2003 Rich,Do the Chrysler and the Jag share the same living quarters?That old Chrysler might get jealous of your attentions to the Jag, and one night will set upon it like "The Gingham Dog and the Calico Cat"("...side by side on the mantel sat...").There seems to be an endless variety of blast media to choose from: sand, silicon carbide, glass bead, plastic, walnut shells...I think I like Ron's "k.i.s.s." approach!A buddy keeps trying to get me to "go halfs" with him on a blast cabinet, and I think I might take him up on it; I can only do so much with the wire wheel (and I get tire of plucking wires out of my arms and legs when I'm done!).(I should probably stop teasing you about the Jag and go try and find my '63 Benz in the snowbanks on my street! Happy blasting!) Link to comment Share on other sites More sharing options...
RoadsterRich Posted February 20, 2003 Author Share Posted February 20, 2003 Frank,Seems that the Chrysler loves the Jag. The more attention I pay the Jag the more guilty I feel about the Chrysler so the more that gets done on it. The two cars are about 40 miles apart as the crow flies, so they are fairly safe. Part of what has slowed the progress down on the Chrysler has been the state of the garage, or more accurately the lack of space. I've been on a cleaning binge (rampage?) for a few days and can get to much more of the garage, another week or two and I will have more room in there than at any time since moving in to the house back in '86. My goal is to get the garage cleaned out enough and cleared out enough (4 generations of stuff ended up stored in there, long story but I'm the repository of all things family it seems) that I can seal the floors and install a small window AC unit (mind you there is no window in the garage... yet).Hey Frank, when are you coming down to help work on the cars? I hear they are anticipating serious flooding up your way, if you have to evacuate let me know, I could use some help with the cars and the garage. (Seriously though, will be putting in a few good words just in case for those that may be facing the anticipated flooding from the melting snow.)Oh and Frank, just remember, snow banks + cars + snow plows = Don't see it again until spring thaw and hope the salt has left something for you to restore.As to the blast cabinet, I'll take all the suggestions I can get. For now I will use Ron's KISS approach as it has served me well professionally for years (well it and the rule of 7P's... Proper Prior Planning Precludes [censored] Poor Perfomance (you can substitute Progress, Products or other P words for Performance)). I forgot to follow the 7P rule or the garage would have been emptied and the tools organized BEFORE acquisition of the Chrysler and subsequent acquisition of the Jaguar.Rich Link to comment Share on other sites More sharing options...
Restorer32 Posted February 20, 2003 Share Posted February 20, 2003 We have a large professional blast cabinet which we have used for 25 years averaging maybe 8 hours/week. We use 1 size nozzle suited to the amount of air we can pump and course glass beads which we purchase in 50 lb buckets from McMaster-Carr. I always start new employees on the bead cabinet cause anyone can do it (except my wife for a very funny reason which I shouldn't discuss here). Absolutely crucial to have clean, dry air. Couldn't live without the thing. We keep a set of pliers in the cabinet to hold small items for blasting, over the years those pliers have become just a shadow of their former self, having been worn to maybe 1/4 of their original mass from all the abuse. Link to comment Share on other sites More sharing options...
poci1957 Posted February 20, 2003 Share Posted February 20, 2003 Rich, I will second what the others are saying, these are very convenient and simpifying with one kind of abrasive is fine. The different size nozzles are not a big deal, actually you will wear them out anyway so I used mine more or less interchangably. 50 psi or less is my air preference too, and the dry air is essential. Best wishes, Todd C Link to comment Share on other sites More sharing options...
RoadsterRich Posted February 20, 2003 Author Share Posted February 20, 2003 Hrrm... Dry air... this is Florida, less then 90% humidity is extremely dry down here. I picked up a filter, regulator and pressure gauge to attach directly to the inlet on the cabinet, seemed to make sense to put them there. I'll have to look in to how to dry the air. Boy every project just grows and grows doesn't it? Ah well, looking forward to the results. I have boxes (and boxes... and boxes...) of pieces parts that I have already cleaned to the wire brush level. There are just certain nooks and crannies that wire brushes can't hit. And I have to second the whole embedded wire bits opinion, I've had more injuries from the wire brush than from any other single tool so far on this project.Off to research 'dry air'... I can see it now, I'm going to have to buy a house in New Mexico or Arizona... one of them arid states <img src="http://www.aaca.org/ubbthreads/images/graemlins/grin.gif" alt="" />Rich Link to comment Share on other sites More sharing options...
Guest DeSoto Frank Posted February 20, 2003 Share Posted February 20, 2003 Rich,The desert SW might shrink the body wood in that Chrysler and it'll fall apart... (IS there a Utopia?)My garage is a "respository" too; the latest issue of "This Old House" magazine arrived last week with the cover story: "Take Back Your Garage !", which my wife waved under my nose while chanting "dumpster....dumpster...dumpster!" <img src="http://www.aaca.org/ubbthreads/images/graemlins/crazy.gif" alt="" />Now that we're shovelled-out from 1-1/2 feet of snow, everyone's worried about warming temps and rain and possible flooding! I'm glad we live on a hill!As for the seven "P"s, wouldn't you know it, I had bought the Benz as a Guinea-pig just two days before I discovered my '64 Valiant convertible(which was too good to pass-up)....I have learned one thing from the Mercedes: I am not at a point in my life where I can cope with restoring an old foreign car!Time to take Mr. Thoreau's advice and "simplify, simplify."Good luck with the garage and everything else going on! <img src="http://www.aaca.org/ubbthreads/images/graemlins/grin.gif" alt="" />Frank Link to comment Share on other sites More sharing options...
ronbarn Posted February 21, 2003 Share Posted February 21, 2003 Rich, at the risk of being accused of redundancy (been accused of much worse <img src="http://www.aaca.org/ubbthreads/images/graemlins/blush.gif" alt="" />) take my "tip" and get a TIP catalog to see how they recommend that you pipe the air connections. It involves going vertical from the compressor, then a downward slight slope to the area where you will use the air, then another verticle pipe to get it to the height of you use component (in this case, the blast cabinet). Determine the height where you want your outlet, Let the latter verticle pipe extend 8 to 12 inches below the outlet position and install a drain valve. Install your filter and regulator between the the outlet and the cabinet. You will be amazed at how much water you trap in that short verticle section. The only thing that I deviate from the TIP recommendations, and at the risk of starting another controversial topic) is that I use PVC pipe - NOT the thin ordinary water pipe, but the stuff rated at 650 psi or higher. Been using my PVC air plumbed stuff for 14 years without a problem. Course I do not have to worry about the PVC getting too brittle in cold weather <img src="http://www.aaca.org/ubbthreads/images/graemlins/tongue.gif" alt="" />Another space tip, if you haven't already figured this one out. Place your compressor outside the garage where the heat dissapation factor will not impact your AC requirements and it will reduce the noise. I poured a small concrete pad and built a cover to protect the compressor. Link to comment Share on other sites More sharing options...
novaman Posted February 21, 2003 Share Posted February 21, 2003 In my Dad's shop I built a 4' wide blasting cabinet. We have water trap plugged into the compressor. Also where I get the air from is a line that goes up over one of the overhead doors. Where it turns up, there is also a line going down which is a water drain. Then where I plug the air line in, is another water trap. This seems to take care of the water except for the personal sweat on the hot & humid NC days. Link to comment Share on other sites More sharing options...
Guest Posted February 21, 2003 Share Posted February 21, 2003 Frank, if you ever need any tips or the odd part and wood on the Benz, let me know, I've been working on the oldies for about 30 years. I know those puppies inside and out. My current project is a cream-puff orpjhan that I could't pass up, a '76 Olds Toronado, baby blue and mint white interior with the last of the 4 bbl 455's. Less than 9k on a totally rebuilt engine and the oriiginal owner with no rust, not a bad car for my kid for $500 , eh? <img src="http://www.aaca.org/ubbthreads/images/graemlins/smirk.gif" alt="" /> My first amercian restoration in about 20 years, and she is called "The Blue Shamu" haha Link to comment Share on other sites More sharing options...
jw24spec6 Posted February 21, 2003 Share Posted February 21, 2003 i would think twice about useing pvc pipe when it fails it all fails, try copper it takes care of the heat. you should have 30 ft of pipe before the first water trap, that allows the water to condense and be removed by the trap fully jim Link to comment Share on other sites More sharing options...
Dave@Moon Posted February 21, 2003 Share Posted February 21, 2003 I've been reading this thread with great interest. I'm currently setting up shop in the "new" house, and I'll be plumbing my air lines probably within the month. At my old house, at the suggestion of several, I used galvanized iron pipe for the air line. I worked well, but after a while the interior of the lines started to rust and my water trap became opaque with browm haze.Campbell-Hausfeld sells a <span style="font-weight: bold">very</span> expensive aluminum air line kit ($150 for a 15' line at Home Depot). Has anyone had any experience with these lines? And is there a more reasonable alternative? My garage gets COLD (see photo gallery for water pipe burst results), so PVC may not be such a great idea. Link to comment Share on other sites More sharing options...
RoadsterRich Posted February 21, 2003 Author Share Posted February 21, 2003 Cold is not an issue, the coldest my garage is likely to see is 45F and even that would be unusual. The garage is more likely to see heat, with temps greater than 100F. I know that iron rusts down here rather quickly so I'd rather not use it. Aluminum might be interesting, copper too, though I have heard of ruptures with copper and aluminum as well, apparently there are various wall thickness as well as various alloy contents affecting the pressure ratings of the pipes. My compressor max's out at 150PSI, though I'd rather build in for 200PSI to cover a possible future expansion to a bigger beefier compressor. Seems there are as many opinions as there are folks to give them. I'll do some research and see how it goes. The AC unit sits between the compressor and the blast cabinet, I could always run the lines through the plenum <img src="http://www.aaca.org/ubbthreads/images/graemlins/tongue.gif" alt="" />Rich PS: It is currently 84F with a humidity of 53% inside the house because I refuse to turn the AC on in the midst of winter and it is too humid outside to open the windows (been raining 100% humidity right now outside, with 74 temperature at 11:15PM). Can you spell stubborn? (or is that stupid?) Link to comment Share on other sites More sharing options...
RoadsterRich Posted February 21, 2003 Author Share Posted February 21, 2003 Furthering the complexity of the question... my compressor manual says that I should empty the compressor tank after every use, not to leave it pressurized for more than an hour of non-use. Is it really necessary to drain it whenever you walk away for an hour? I generally use my tools off and on throughout the day, often 3 to 4 hours go by between uses. So I guess the real questions are:1) How frequently should you drain the tank?2) When/how frequently should you decompress the tank?3) Why does an oil-less compressor tell you to have it serviced and oiled annually?And a note on compressor safety, and general common sense, something I seem to have been lacking when I installed my compressor. I purchased a brand new Sears Craftsmen 6HP 30 Gallon vertical compressor. I got it home and the installation instructions consisted of installing 2 wheels and 2 rubber feet. Took all of 10 minutes. I then wheeled the compressor over to it's new home and plugged it in. I followed the break in procedure, run the compressor for 15 minutes with the drain valve open. Close the drain valve and let the compressor build up to pressure and shut off. Decompress tank to 20lbs using the pressure releif valve, then open the drain valve to allow the compressor to finish decompressing (and pee on the floor). First part went great, put pressurizing the tank did not. 10 minutes... 20 minutes... 30 minutes... still not pressurized... 40 minutes... and it still is not even to 130PSI... something is amiss. I double check, the regulator is set to 0 (off), and there is no air coming from the outlet which is correct with it set to 0PSI. I scratch my head, shut everything down, disconnect everything, reconnect everything. This time, 45 minutes later the tank is finally full enough for the compressor to shut off (150PSI compressor, it shuts off at 140PSI). Okay, I know it should not take this compressor 45 minutes to fill the tank, I have an ancient Craftsmen with a kelvinator compressor head and a 3/4HP motor that could fill a 30 Gallon tank in 30 minutes easily (albeit only to 115PSI). Okay obviously something is amiss. I drain the tank, and start over yet again. This time I notice that the needle fluctuates a great deal +/- 15PSI as the compressor runs up, the first 50PSI happen in no time, then the compressor gets much louder and every additional 10PSI dramatically increases in time. Suddenly in some brilliant flash of genius (well maybe just my common sense kicking in) I shut everything down and drain the tank. I check the fittings for the tube that runs from the inlet check valve on the tank (on the compressor side, not tank side) to the pressure switch. Lo and behold these are not even finger tight! I tighten both of these up and check every other fitting I can find. All other fittings are perfectly fine, but not these two, they could have literally blown off at any time (and at 140PSI I imagine that would have been somewhat spectacular). I plug everything back in, double check everything (including fittings) one more time, and fire the compressor up. In seemingly no time the compressor shuts off with a full tank at 140PSI and no fluctuations in the gauge, just a steady increase till full. Also the compressor is running much quieter and much cooler. Go figure. And the moral of this story is, ALWAYS check all of the fittings on new equipment, never trust the manufacturer or their quality assurance programs. I called Sears about this and was promptly blown off, it seems that Craftsmen customer service is a thing of the past...Rich Link to comment Share on other sites More sharing options...
Paul S Posted February 21, 2003 Share Posted February 21, 2003 I have seen sch. 80 PVC blow apart with no more than 100 psi of air. The joints usually do not fail, the fittings blow apart into shrapnel!! There is a special green colored PVC that is safe for air, we have never used it, just went back to black iron. As far as depressurizing at the end of every day <img src="http://www.aaca.org/ubbthreads/images/graemlins/confused.gif" alt="" />. I think the expansion and contraction of the tank every day would be alot harder on it than being under pressure all the time. Link to comment Share on other sites More sharing options...
ply33 Posted February 21, 2003 Share Posted February 21, 2003 I suspect the "requirement" for de-pressurizing the tank and draining it is simply to safely keep condensation from accumulating in the bottom. My compressor came with a drain valve that looked something like the one on the radiator of my antique car. And it was located at the very bottom of the tank. The combination meant that it was hard to get it tight enough to seal if there was pressure in the tank. In addition, anything that is being blown out when the tank has 100 or 200 psi in it can be moving dangerously fast with your hand in the middle of it.I plumbed it out to where I could install a nice ball valve and then have the outlet facing in a safe direction. It is easy now to crack the valve open periodically to drain any condensate and then close it without having to worry about the valve sealing or being blasted by high pressure spray.As to pipe: Any pipe can fail given enough pressure or enough abuse. Typical metal pipe will split and vent its contents without explosively sending shards all over. This is the reason it is considered safer than plastic.I have used galvanized pipe at a previous house. My current preference is copper: I can get it at the local hardware store. I find it easier to cut and make leak free joints than the iron pipe. And, since copper is a good thermal conductor, I believe that the compressed air will be down to ambient temperature before it gets to my first outlet so the water traps should work well. I also don't expect it to rust out from the inside from any condensation. Link to comment Share on other sites More sharing options...
jw24spec6 Posted February 22, 2003 Share Posted February 22, 2003 as far as professional recomendations have gone at my shop, it has been copper or the aluminum both cost money. its illegal here to use pvc so i dont jim Link to comment Share on other sites More sharing options...
Paul S Posted February 22, 2003 Share Posted February 22, 2003 Copper requires a different type solder after a certain PSI and pipe size. I have the chart somewhere, if I can find it I will try to post it. From what I can remember 1/2" & 3/4" is pretty safe up to a decent pressure with regular solder. Link to comment Share on other sites More sharing options...
Al Smeraldo Posted February 22, 2003 Share Posted February 22, 2003 Copper tubing comes in different wall thicknesses. Years ago I worked for a plumber. There were 3 wall thicknesses at the time L, M, & T . L= light M = medium, T I can't remember what it stood for but it was the heaviest. Watch what you get at your supplier. Al Link to comment Share on other sites More sharing options...
Guest DeSoto Frank Posted February 27, 2003 Share Posted February 27, 2003 Hey, Master Wrench !I sent you a private message on the Forum asking your help on my Benz!Did it get through to you? (Is there an envelope flashing at the top of your display?)At any rate, get in touch w/ me when you can- I'd like to pickyour brain a little...Thanks in advance!De Soto Frank Link to comment Share on other sites More sharing options...
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