Is this enough compressor?

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Inspector71

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I've decided to paint my own cars. I had some experience as a helper years ago and have sanded, taped, primered and all that and I like it. But I want to paint my own cars. Would an electric air compressor, 3.7 hp, 60 gallon, be enough compressor for the job? Thanks for the help.
 
Plenty and tons to spare.

If you use old school guns, it's plenty....should be plenty of CFM for the gun. (look at the specs for CFM rating.....it depends on the rpm of the motor, size of the piston, etc.......but it sounds OK....I've used less).

If you use new HVLP guns, it's WAY plenty.
 
Your going to want to see what the CFM rating of your compressor is. Then see what your paint gun CFM requirements are. Your compressor is most likely around 10 to 12 CFM @90psi if it is a single stage, there should be a tag on it somewhere that would tell you.
 
Yes, you need to look at CFM ratings. Also, be aware a LOT of crappy compressor makers rate their compressors at ZERO PSI to make their CFM ratings seem large. You will want a high CFM rating at a reasonable PSI, such as the 10-12 CFM @ 90 PSI stansblue72 gave as an example. That's a good rating. Probably don't want to pick one rated at under 90 PSI because that is a good operating PSI and that's what most air tools are rated for.
 
My compressor is a 60 gal porter cable that is rated at 11cfm @ 90 cfm. It is plenty of air but just be aware the head and motor stay cool via air circulation. A small cooling fan blowing across the motor and head can help it tremendously especially in the hotter months.Be sure to use moisture traps as well.
 
This is definitely the place to be. I can't thank you all enough for the answers. It has been many years since I played around with painting and I know nothing. This will be great advice for the summer. I'll let everyone know how it turns out. I plan to start in the engine compartment and move on to the trunk area. I am turning a B-3 blue Barracuda into (got the code somewhere) metallic turquoise from the 69 Road Runner. I had a 63 Valiant painted that color and loved it. During the day, it looked like turquoise but turned an ice blue at night. I decided to learn to do more work myself.
 
stansblue72 said:
Your going to want to see what the CFM rating of your compressor is. Then see what your paint gun CFM requirements are. Your compressor is most likely around 10 to 12 CFM @90psi if it is a single stage, there should be a tag on it somewhere that would tell you.
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Thanks for the pictures. I wanted to buy a 62 Fury not long ago until I climbed under. I could pieces of the flioor board off like dried up paper. There was no way to save the 72?
 
StrokerScamp said:
a LOT of crappy compressor makers rate their compressors at ZERO PSI to make their CFM ratings seem large. .
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READ the above AGAIN. THIS is the big problem with ratings. Some are rated at SCFM ---INTAKE air, NOT the high pressure output, and some are rated at 40 PSI, NOT at 90 PSI which is what your air tools are rated at.



Also, don't get too excited about gallon capacity of the tank. IF THE PUMP cannot keep up with the flow, then the TANK SIZE is only going to give you a few seconds/ minutes of reserve before the pump cannot keep up.

Don't get too excited about HP ratings. HP used to be a very "honorable" rating, but no more.

Make sure the CFM rating at 90 psi gives you PLENTY of reserve, but a BELT DRIVE system, NOT direct drive and STAY AWAY from these ridiculous high-RPM oil-less compressors.

Plumbing the shop and air dryers is a whole other ballgame
 
Good advise 67dart273 especially regarding the oilless comp. Those things are junk...
 
That's probably pretty good. Find out the requirements for something that takes a lot of air to run....like a paint gun or a sand blaster. If the CFM rating is less than that compressor at or close to that 90 PSI, it will do the job. That sounds like a right good rating though. I just cobbled me up a big compressor about two months ago. It has a Kellogg American 120 gallon horizontal tank, a Harbor Freight 2 cylinder single stage pump and a 5 HP 220 volt motor. Heck if I know what it's rated at now, BUT it runs my blasting cabinet and the compressor will pump up and cut OFF while I am blasting, so I know it produces more CFM than I am using. I also know that if it does that, it is plenty big enough to paint a car or do anything else. Remember, the size of the compressor tank has nothing to do with CFM. That is a function of the compressor pump and the pump speed. And speaking of pump speed, any good air compressor shop will tell you that it is best for your pump to have a pump speed around 750 RPM. Most store bought compressors spin the pumps much faster to compensate for a cheap or undersized pump. That's why you won't really get a "good" compressor until you get into the higher dollar amounts from "discount" stores. I have a smaller Husky 30 gallon compressor that I traded fixin a lawn mower for. It had a bad motor on it. I bought the cheapest chinese replacement I could find....BUT I also got a smaller pulley for it at the same time to get the pump speed down to about 750 RPM. That does two things. It gives the motor more leverage to spin the pump, reducing the load on the motor. It also makes the pump last longer cause it ain't spinnin its *** off. I use the little Husky for everything else but blastin or paintin....I haven't done any paintin yet, but I know the big compressor will do it. Moisture control is also another real important thing to consider. You need a GOOD moisture filter. I just make my own outta PVC. I run a tee in the line and drop a section of PVC down almost to the floor and put a plug in the bottom of it with a drain **** in it. The moisture will automatically drop into the trap and you can drain it out. You need to keep the compressor tank drained too. If you read up on them, compressors are simple beasts and are pretty easy to make yourself....you can save a lot of money and usually end up with better than what you can buy from a store.
 
SS is right about researching air requirments. I think you'll be pretty safe with that compressor though. I found the biggest air pig I have to be my da sander.Was using it to cut polish (with a polish pad on it) my old cop car and man,did that sucker ever pull air. I actually had to give the poor comp a rest!
 
Until I posted this question, I didn't fully realize how important it was to research the equipment. I was focused only on the painting part of this process. You all have saved me some big headaches and mistakes I am sure I would have made. I am really looking forward to learning to paint for myself. Please accept my apologies for such a tardy response. It is the end of the semester and there is so much to grade. I got caught up in the paper work blizzard.
 
All I would chime in and say is make darn sure it's a two stage compressor. Tank size is a small consideration to me. It has to be a two stage compressor to keep up with a paint gun or it will run itself to death. My compressor will go clear down to 15psi and still run my DA sander.
 
Carpainter said:
make darn sure it's a two stage compressor. ............ It has to be a two stage compressor to keep up.
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A two stage does not mean "high volume." In fact, it could mean "less."

Biggest things are:

True rated motor HP, and cast iron, OILED compressor pump and BELT not direct drive. Good quality unit with "history" and parts availability. True CFM rated at 90PSI OUTPUT not SCFM

You are correct, though, if the pump can't keep up, a great big tank won't help.
 
67Dart273 said:
A two stage does not mean "high volume." In fact, it could mean "less."

Biggest things are:

True rated motor HP, and cast iron, OILED compressor pump and BELT not direct drive. Good quality unit with "history" and parts availability. True CFM rated at 90PSI OUTPUT not SCFM

You are correct, though, if the pump can't keep up, a great big tank won't help.
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Yes good point :thumbup:
 
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