Technical What kind of gun to paint a car with a small compressor??

Hi. I will be painting a 1937 Ford Tudor Sedan the late Spring. I want to spray it a single stage urethane Bright White. I have a 21 gallon compressor. I bought a HVLP gun, but was told it won't work because of the compressor. Was told to go LVLP. Then was told that I could only do panels. I would like to paint it myself, because I did everything else by myself. Can either of these guns work for me?? Thanks.

 

Or do I need to go back to the old siphon feed??

 

What is the CFM rating of the compressor? A HF purple gun uses 6-8 CFM @ 40 PSI with a 1.4 tip, their touch-up gun 3-4 CFM with a 1.0 tip, and their siphon gun 8-9 CFM. That is typical. With only a 21 gallon tank, probably not enough reserve capacity to do anything beyond a touch up gun if that.

 

Simply put, the CFM capacity of your compressor needs to exceed the CFM requirement of whatever gun you choose. 21 gallons is the size of the tank, has no relation to the CFM that the pump can deliver.

 

7.7@40 psi 6. @ 90 psi

 

What he said. Btw those 37 Fords are cool!


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I have the kobalt 30 gallon tank, think it is about 6 cfm at 90 psi. And the $15 purple hvlp gun from harbor freight.
While I have never painted a complete car, I have painted the cab and the fenders hanging on the clothes line. Sure as a noob I had several issues to overcome, air was not one of them.

I am spraying rustoleum primer and paint, not sure if different air requirements for enamel vrs urethane.

I think your compressor will work fine and the cheap gun from harbor freight works really well. Be sure to clean the grease out of it before using.

 

Biggest problem with such a small compressor is it is going to be running constantly and you are going to get a LOT of water in the tank so you will have to have a very good method of removing moisture or you are going to have major problems.

 

My advice would be to buy a gun regulator fill the compressor and set regulator at 2 bar. Hold the trigger on and see if you’re compressor can keep the pressure at 2 bar when it’s emptied the tank and whilst it’s running. It could still be very hard on your compressor and you may still have to work it so it can have a break to cool. Actual pressure whilst you’re painting will vary but 2 bar is where I start
Luke

 

I painted a square body longbed pickup with my 21 gal compressor out in my barn a couple years back with a gravity fed gun. It worked pretty good. Just dont get in a hurry. Invest in a couple of in line hose filters from harbor fart and they tend to help with the moisture build up. Set your regulator and go to town with it! Good luck. It can be done!!!!


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Rent a compressor for the day

 

Something like the original Eastwood concours might. I have a purple H.F. gun and that size compressor won't keep up. You can panel paint some areas but when you get to the top of the car, it's going to be tough to not have dry spots.

 

That would be a viable option.

Another option would be to find a larger but not huge used compressor tank to use as a "reserve" tank. I've got what is about a 30 gallon tank that I bought to put the compressor and motor off an old compressor that had a rusted out tank on years ago then bent the crank on the compressor when I dropped it that works pretty good as a reserve tank with my small compressor hooked to it. Hose in hose out and no fancy hookup with a pressure gauge and nothing else on it. I don't use it all the time but it will let me air a couple of tires up without the compressor kicking on.

 

I read about these LVLP guns, saw one in a Princess Auto flyer; it was cheap so I bought one. Took it out of the box. It is very small. Still haven't tried it yet.

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one problem with a small unit is it will run constantly, which gets the pump hot, and therefore the air is hot. hot air makes condensation, like K13 said, and hot air will make the paint want to set up faster, not allowing it to flow out orange peel, and leave dry spots. mr 48 chevs idea of another tank in the system will help. use hotter temp reducer will help too

 

People borrow my old Sears roll around compressor all the time, got any friends?

 

Home Depot has a Spray-it LVLP gun Air Consumption 2.4 to 3.9 cfm @ 30 psi. Working Pressure 28-45 psi. Max Pressure 60 psi. Now would this work with my compressor??

 

Could always run the hose threw a tub of ice..

 

You will likely have your regulator dialed down to 40-45 psi- I am sure you can paint it in pieces and be fine- when you go to do the body there is mainly the roof and rear quarters.
Because you are painting it solid white - I would not anticipate problems with the panels matching if painted on different days or temp- but because you are painting in pieces you will waste more paint- so buy extra and make sure you mix all of it together before you spray anything so the color is all exactly the same.

 

A Finex 3000 is a decent gun that sprays slow. Definitely what you want with little experience.

 

I would try a detail gun. Small capacity, and do it a panel at a time.

 

Maybe a couple of cases of rattle cans..

 

I have painted a full size pickup truck with a DeVilbis syphon feed gun and 2 hp compressor. Had to stop once in a while to let it build up pressure but it did the job eventually. A gravity feed gun should use a lot less air. Put a water trap on the compressor and don't worry about it. A gun regulator is a good idea but not absolutely necessary. If you suspect water or oil in the hose buy a new hose. Drain the tank before you start.

 

We used an LVLP gun and 10 gallon compressor to paint my car, plus a cheap regulartor and water filter. The gun was $100 on Amazon and worked great. However, it is a very small car.

 

Brilliant idea.

 

you could buy a cheap air compressor and hook them together with a tee. running both at the same time.

 

HVLP= High Volume Low Pressure! HVLP guns are designed to atomize paint at low pressure at the air cap { less over spray} but to do it they take a lot of volume . Have used them for 36 years, your compressor will not keep up . Know matter what gun you try It will not produce a decent finish. Take in account what you will save not taking it somewhere and go and buy yourself a 5 hp 2 stage cast iron pump, 60 gallon compressor and have a tool that will last and provide you with enough air supply for what ever you need in a hobby shop. My brother bought one from Tractor supply for about 800.00 dollars. My compressors are both 10 hp ,4 cylinder ,80 gallon tank units that cost 2,500 a piece 20 years ago but I also had a shop with 5 employees . I still use them all the time. So yes I know what I am talking about. Good luck with your project. Larry

 

Are you taking it apart to paint?
I use a gravity feed gun, doesn't take much pressure.

 

I really don't want to take it apart again. Though I can. saltflats. What kind of gun do you use?? All I want to paint is a single stage paint. Tamco paint has a single stage that has the clear already in it. Some say go with the HVLP, while others say that I can do it with a LVLP gun. One guy said use a touch up gun. 2 cases of rattle cans would probably do just as good a job. Places I have brought the car to said. $15,000. They all want to take it all the way back down to bare metal. I can't afford 15k What is a guy who is willing to paint his own car but only has a small compressor suppose to do??

 

3/8" hose with the large bore coupling fittings will help by reducing the line and fitting losses that will get more out of a compressor. Use a filter and regulator that can comfortably flow more than the compressor can put out . A mini regulator at the gun will make sure the pressure in the lines has made it to the gun. Eliminating as much of the pressure losses and flow restrictions will make a difference. The smaller tank and compressor is likely to do a good continuous run until it quickly can't keep up.

I would suggest seeing if you could borrow a larger compressor or rent one for the day. There are tool and equipment rentals that rent gas powered compressors. If there is a United Rentals in your area then check with them. I have rented a fair bit of tools from our local United Rentals. If they don't have the size you are looking for they usually will bring it in from a neighbouring UR rental store. The local UR is always shuttling equipment between branches. They list gas powered in the 12-15 cfm range. Their may be a commercial paint contractor that has gas powered compressors that may rent one for a week end. My son bought a nice gas powered compressor from a paint contracting company.