What Size Air Compressor To Paint a Car?
We got a new question from a loyal subscriber of learnautobdyandpaint.com
“Hi Tony, im new to the auto body/paint world and just want to ask: What is the reason for needing a 50 – 60 gallon compressor? and why cant i use a 25-30 gallon compressor for a complete paint job? if due to pressure variation. Can we paint the whole car by steps? say one side, let the compressor fill up, then the front, let the compressor fill up, then the other side, again, let the compressor fill up then finish with the back of the car. If this is possible, can you teach us how..?”
With a small air compressor tank you simply don’t have the air volume (cfm) to paint an entire car at one shot. Your gun will strain and struggle.
Your smaller tank will most likely run out of air while you’re spraying non stop… going around a full car at once etc…
You can take a chance and paint the entire car at one shot if you can hear and feel the air pressure drop and adjust accordingly. (I’ve done it) and had no problems because of so many years of experience painting cars.
By doing this (You will also have condensation problems) your smaller tank WILL get hot and create water because of constantly being on and running. See, water usually builds up in tanks anyway, that’s why you have a drain at the bottom of your air compressor tank. Also be sure to drain it once in a while. More often if you have a smaller tank.
When painting with a smaller tank like a 15-25 gallon …you’ll have to keep draining the tank every 2-3 passes around the car just to be safe. OR, leave it cracked a little so as water builds up it will automatically drain out. It’s also wise to have a (in-line) water separator off your tank about 10-15 feet from your tank and one at the neck of your gun. This goes for small compressors or big shop style. It’s just good insurance to have.
Painting a Car
The tricky part… YES, you can paint the car in steps (same day) with a smaller air compressor but you may run into problems with overspray on the clear coat stage. When laying clear on the car you want to spray it on at once because if you wait too long and spray you will make your other glossy clear panels dull from the overspray that you create. You have a certain time frame where overspray will just melt into fresh clear coat, which is what painting flash times are all about. More on this within the VIP cub.
When freshly sprayed clear coat becomes tacky and you create more overspray by spraying other adjacent panels because you had to wait for your tank to refill etc…
The overspray from the clear coat will cause your job look dull. Of course if you plan to completely color sand and buff you wouldn’t have a problem. What you can do is, if not painting with candy, flake or pearl… paint the hood, the front bumper and your two front fenders at once.
You know, two coats of base and two coats of clear coat. Let that completely dry, then a day or two later mask all of the painted parts, then paint your roof, and doors that day, and a few days later do your rear quarter panels, trunk and rear bumper to complete the job.
That way you complete the job till the end and you won’t have overspray nor will you need to buff.
It will basically take 3 days painting to paint your car.
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