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Total paint noob right here! (Bought a 7-gallon compressor today...)

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...and I don't think the 7-gallon tank will be enough? What I got is a Craftsman 7-gallon compressor which runs 2.4SCFM@90PSI/3.7SCFM@40PSI. I have a spray paint gun that uses 1.6~4.0CFM that operates at 50-70PSI. Now that I look more carefully, members on this site have 20 gallon tanks and whatnot. I don't think I'll be able to store a tank bigger than 15 gallons in my garage unless I can keep it outside without getting it stolen... What if I try painting the car one body panel at a time? How would that work out?


Basically what I'm trying to do is to learn how to spray paint car body panels. Eventually I'll be able to get enough experience to apply it on my future 240Z. Now that being said...


...sanding down just ONE fender is a toughass job (trying to fix up my current ride, Acura Integra LS year 2000 model). It feels like the 400 grit sandpaper only lasts for 5 minutes of rough sanding. The fender that I'm talking about is an "extra/used/stolen/god knows how this guy got it" fender that I got from a craigslist dealer for 20 bucks. Not the best looking fender (has a little bit of rust but nothing serious) but it looks decent and dent-free enough to be able to replace it with my old one (acquaintance of mine damaged it by ramming my car into a deer on Stevens Canyon :sour: )


ANYWAY, I'm almost done sanding down my extra fender, but I'm not sure what to do about the little cracks on the edges. I'm not entirely sure if the cracks will be noticeable once I install the extra fender on my car anyways. But it's always better to be safe than sorry, so perhaps I should NOT cut corners and do everything I'm supposed to do. Oh, I did sand all the way down to bare metal on parts here and there so I got self-etching enamel primer from Kragen's. Would it adhere with the factory primer?


Oh, and here are the pictures for reference!






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I'd recommend taking the compressor you bought back to the store (if you only bought it to spray the fender.) You should probably take that fender to a reputable shop and have them at least spray the top coat and clear coat to match your car.


I really doubt 7 gallons will be enough air. And that scfm rating is not enough to use a quality gun.


When it comes to body work, you don't want to rush anything. Do it right once the first time.

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Alright, I guess it's not the time for me to buy an air compressor right now. Once I get my own place then I'll get a quality compressor, gun, etc. But regarding my replacement fender, I really do want to learn how to spray paint correctly. Someone told me that there are auto paint shops that have paints that would match the color code of my Integra in spray paint cans. I don't really mind messing up this replacement fender since all the stuff I bought to paint it ended up being much more expensive anyway. I'd much rather work on a car that I don't really care about than mess up on a car I actually admire.


If I put enough primer over the cracks, do you think it'll work out?

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What would make a good air compressor for a small garage and low price?


I'm just speculating, but I'm thinking that a compressor with a high enough rating (higher than the spray paint gun's requirement by 15-20%) so it gives it constant pressure without relying on the tank. That's what I THINK, not sure if it's true. I'm just saying this after all the reading I've done and I still may be wrong.

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Well you've taken enough grief about the compressor already. I'll give some info on the prep :)


You sanded it with 400 grit, from the factory finish to that? Yikes. Normally you'd start in the 80 grit range, do some hammer and / or bondo work, then 120, repeat the bondo, 220 grit, spray some primer, block it down with 400, tack it off and spray your color.


I wouldn't fret about the bare metal, just prime it. Etching primer is funny stuff, to me anyway, I'd go to the auto paint store and buy some standard aerosol primer - whatever they recommend. I don't think you can always put it on top of other primers. Caveat emptor.


Yes you can buy premixed paint in aerosol cans. You have a set period of time from once they mix it till it hardens up and you're SOL. I believe its comparatively expensive, but that's the convenience tax you pay. Grassroots Motorsports did an article on it fairly recently, doing body work on their saab and e30.


See if they'll put a single stage urethane in there for you. That way you can skip the clear. If your paint is a solid color - not a metallic - that's the way to go.


For the cuts in the metal - I had the same thing on a fender. I hammed and dolly'd the area, tack welded it from the inside, and said "good enough". On the Z, its behind the headlight bucket so nobody sees it anyway.



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I think a 7 gallon is fine for a beginner. Kinda limits his spraying periods and forces him to stop and way until he sprays the next layer.


As for body work, this is what I do.


1. pound out the dents to as straight as possible. If it looks like crumpled up paper, that is fine. The point is to use the least amount of filler as possible.


2. Apply a thin layer of filler expecting most of it to be sanded off.


3. Sand. start off with a 60 or 80 grit to just form it. I use a rag and some acetone to remove some of the tacky surface film before sanding so it doesn't gum up the sandpaper as much. Use your hands to feel where hi's and lows are.


4. Once its formed, there will be some scratches for the sand paper. I put another really thin layer of filler just to fill in the scratches and then use maybe a 150 grit and then move my way up to about a 600 grit.


Another word of advice. Use a primer, paint will react differently from metal to filler. And spray as if you are misting the car. Many very thin layers is always better than one really thick layer :P

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I painted the rear half of my car with a 2.5 peak hp compressor with a 20 gallon tank. I used a small cup gun, and ran the compressor at about 25psi to the gun, and the pump ran about 70% of the time. I paused in a few key areas to let the compressor catch up.


I wouldn't recommend doing it this way, but it is what I had, and I made it work.


From my understanding, it is not so much the size of the tank, but the ability of the compressor to keep it pressured under constant use. Depending on the type of tools you are using, this ability will vary. My compressor will not keep up with much more than a hobby spray gun on a constant basis, but it is sufficient for my current needs.

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