compressor size for painting
- Thread starter rubicon
- Start date
Also used the 'purple gun' from Harbor Freight with my 2 hp compressor to spray two component high fill primer, and single stage urethane finish coat. The gun has an attached regulator to keep the pressure at 45 PSI, and my compressor will deliver 5 CFM at that pressure; it is rated at max of 115 PSI.
I bought a (recommended) spray gun years ago (young and thought I knew everything ) only to find out afterwards it needed a minimum of 10 CFM to operate properly, compressor was rated @ 8CFM and actually delivered 6.2 CFM. Waste of money still sitting on the shelf in the shed.
fletcherson
Well-Known Member
You can get away with a smaller compressor if you have additional air storage, i.e. additional remote air tank. The key is if you use a smaller compressor is to plan your spray so you can do it in sections. Honestly, if you are going to invest in a compressor, I would look for at least a three horse power with the largest tank you have space for. The biggest one you can afford. It will last longer because it won't work as hard and you will be able to use any air tools. You will have more issues running sanders, grinders, etc than painting. It really kills momentum to have to stop working and wait for the compressor to catch up. I have a industrial five horse four cylinder and a farm duty seven horse two cylinder... the old five horse works much better, but they both have large tanks and I have a five hundred gallon propane tank that I use for reserve air...overkill for sure, but I had it, so I used it...my compressor hardly runs when spraying due to the air volume on reserve.
tdkkart
Member
My home built compressor has a 120 gal tank, 3 cylinder single stage pump that delivers approx. 13cfm, max pressure 120psi, When I painted my car the compressor came on within about 30 seconds of being done with each coat, so it was doing it's refilling while I was mixing paint. Big tank makes a big difference, as does using large air line to deliver the air, which equals less pressure drop at the gun and more consistent air delivery.
rubicon
Active Member
Good to know. Thanks
fletcherson
Well-Known Member
The noise issue is a real concern. I have my shop compressor mounted in the attic, insulated, and it really cuts down the space,, noise, and dirt that the compressor breaths. Also, I built custom air filters for them and use car air filters. They are larger, cheaper, work fine, and require changing muss less. Besides that, some compressor filters are difficult to get when you need them and are prone to clogging up when spraying if the compressor is in the shop with you. Another very worthy add on is installing a air conditioner condenser In line directly after the compressor head, before the tank, with a catch can. It removes virtually all of the moisture and was a inexpensive addition made mainly from scrap. Look it up on line if it interests you.
rubicon
Active Member
Thanks for the info. I've been checking on line and saw how a guy used a car muffler to help on the noise problem. What if you vented the intakes to the outside. Would that cut down on the noise?
I like the idea of car filters.
2old2fast
Active Member
Most electric compessor mtors are open frame [they use air from the outside for cooling .] If you want your compressor to live , mount it so you can filter the air [boxed in w/furnace filters]. If you operate it in the shop air that has bondo dust , primer dust , paint dust etc that is drawn into the motor will coat the hot windings, eventually causing them to overheat & fail....1st 5 hp motor 35 years ago lasted 2 years , the 2nd has been on ever since..
fletcherson
Well-Known Member
The problem with outside air is the temperature variance can cause excessive moisture to build up. If you are in a climate where the outside air is close to the inside air where the compressor is, that's a good idea. I have seen guys install their compressors in sheds and even build dog house type structures to house their compressors to get them out of the shop, avoid noise, and get clean air. All good ideas, depending on the circumstances. I have my drain plumbed so it exits outside to make tank draining easier, but the valve has to be inside because I had one freeze and crack, the compressor then ran until it eventually blew the capacitor, thankfully, not the motor, as I was out of town when it happened. Of course I live in Ohio, so it gets cold here... another thing to consider is if you are in a colder climate, the compressor should have some heat to keep the oil flowing. A simple light bulb or heat light will do. There are also thermo cube devices that you simply plug into an outlet and plug the light into. They are a thermostat controlled switch that turn on and off at predetermined temps. I use them in the chicken coup to control the water heater and heat lamps...again, it gets cold here.
EX JUNK
Moderator
Gary49
Active Member
I moved to Florida from Ohio too. In 2001 from down on the river across from Wheeling, WV.
EX JUNK
Moderator
We were not that far apart as I lived in Canfield, Ohio which is outside of Youngstown.
Jim
fletcherson
Well-Known Member
I have relatives all over fla... we could live there but I own too much real estate and related here in white hell, relocating is a nightmarish vision... we have and are considering the snowbird thing, but more isn't always more. It's difficult to manage property from twelve hundred miles away... If I sell our farm, I know that I will never again possess anything like it and I'm not quite ready to give it up. I hate our winters, but I don't like fla summers either. I guess I'd eventually adjust. My father in law, who I used to work with building houses, etc, relocated to Englewood and absolutely hates it. He's bored out of his mind and hates the summer heat. His experience weighs heavy on my mind.
EX JUNK
Moderator
Personally, I don't like any temperature that's below my age which is 75 and soon to be 76!
Jim
