Thread: painting with a small compressor

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I noticed that there were several people in a previous thread that said they have used a smaller compressor succesfully to paint cars. I have a 3 hp 35 gallon that puts out about 7cfm at 40psi. Good for a portable, but a little below the recomendations for most guns and sanders. I know all of the reasons for getting a larger compressor and when I build my shop, thats the first thing I plan to get, but in the meantime I plan on painting at least one car with it, so any tips on making it work? One question i have is how to filter the air, since i cant install a hardline trap or filter. would a screw on disposable filter at the gun or sander be enough? Any tips or ideas would be appreciated.
thanks

maby a couple storage tanks tied in to a simple air system, dry air regulator at the end of it. should keep up to a conventional gun anyway

If the compressor doesn't meet the CFM requirements of the gun it's just not going to work right..... As for using it with a DA, maybe but it won't keep up at all and dang near impossible to use an inline sander.... Another thing, a little compressor having to work so hard to keep up is going to generate a lot of heat and a lot of moisture, a final filter at the gun isn't going to provide sufficient filtration... Maybe check in to renting or borrowing a bigger compressor or renting somebody's paint booth to apply the paint? Check with your friends that do body work and see if they can help you out...

For years all I had was a little Sears 20 gallon, 1.5 HP compressor and painted a few cars and boats with it. I even painted my '27 foot cruiser with two part urethane with it, an it came out like glass. It was fine for spraying paint, but things like sanders would run it dry.

No real secrets, but the newer High Volume, Low Pressure spray guns are much better than the old siphon guns IMO. I love the gravity feed guns, and they clean up so much easier. I just went to Harbor Freight to get a new gun to suppliment my Craftsman gun, and ended up buying 5 of thier gravity feed guns that were on sale for $ 9.95 each. The darned things worked great and I got as good of results as the more expensive guns I own.

There is no question that a big air compressor is one of the hardest working, most used tools in any shop, but that doesn't mean you absolutely can't do work without one. My shop compressor just fried a motor last weekend, and to get us out of a jam we bought a Harbor Freight on sale $ 149 3 hp/21 gallon model, and it got the job done. But boy is it noisy !!!!!!!!!

Oh, I have also used those round water filters that screw on right at the gun and they work great........just be sure to toss it if you start seeing water and put a new one on.



Don

good advice so far, I have actually found a DA sander and a hvlp gravity gun that are within my cfm range, and other than maybe pausing to let the compressor catch up, i'm not actually too worried about spraying paint with it, but because the DA sander will be used for much longer, I'm concerned about moisture buildup, I guess I can just change the disposable filter often and use a separate air hose for the paint gun, and hope for the best. Also, i'm just doing a cheap paint job to get some more experience under my belt, so the stakes aren't too high. If I still have the car when my shop is done I'll repaint with a larger compressor

the small compressor can work but bigger is better . they can make alot of water and paint will not mix and if you over work the small pump you will push oil and the air line can we say FISH EYES you need many water traps not just one on the gun .the ones like denny has and one on the gun is what i use many years i all ways run 3 traps. i allways put a new throw away trap on the gun every time i shot the finsh paint was much cheaper then a repaint with the price of paint now days

I'm using a 6.5Hp, 35 gallon 230VAC I-R compressor and it will keep up with all my tools but is only rated at 50% duty cycle, which I occasionally push hard - so it could be better though it is rated for 13.5cfm @40psig and 11@40psig

Small air (all !) compressors equals heat. Since heated and compressed airis able to hold a lot of moisture (think a humid summer day) you need a significant length of piping to allow this heated air to cool some and drop out the entrained moisture in a trap. The little bitty ones sold at Lowes or Home Depot will not do the job.

I'm using about 50 feet of 1/2 copper, a Harbor Freight primary filter and a good Sharpe final filter along with a pressure regulator(separate photo) which isn't shown installed - I did a bunch of replumbing after I took the photo. There is a valve at the first vertical leg then the one shown which I use to drain the system. Centrifugal force and a couple of 90 degree bends knocks some water into valved legs - it works. The HF filter collects most of the moisture and I have to drain after each use. The Sharpe is a self draining filter and dribbles a little bit. I usually also use a last chance filter at the gun, depending on how much I'm painting.

My primary gun is an Iwata LPH400-144LV with my primer/rough work gun being a DeVillbiss Finish Line lll. The Iwata uses 9 to 16psig at the gun air inlet at and something less then 8-9 CFM. The Devil is 20-25psig at the inlet and about 9 CFM. The Iwata is a premium gun while the Devil is a handyman-occasional use gun, but doing a good job for its intended purpose. Tools make the job - you may not need pro level as a hobbist, but mid level at least make it more enjoyable.