Help with compressor

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eb0248

I have 2 boats, both 25' with 9 ' beams to paint. Talked to Barry at SPI, great guy. He says 7HP/80 gal is about the lowest for HVLP. Found a working ChargeAir Pro 6HP/60 gal 230 V just around the corner of my house for $250. Do you think that's enough? I've been looking at compressors for 2 weeks. Any help is welcome. Thanks, Ed
 
I don't have the posted CFM on it, going to take a look in the morning. Is 10-15 CFM what I need?
 
Depends on the gun.


I have a 15.9cfm on mine, would never consider anything less. It is 5hp 2-stage/80gal. tank on 220v. That is a baby size compared to a shop.
 
I think it's a two stage, is the 15.9cfm @ 90psi? Just want to compare apples to apples. I think I'm just shy of what I need. The gun is from a Vaper kit Barry from SPI told me about.
 
Check this out:

http://www.truetex.com/aircompressors.htm

For example, a high quality compressor like a 5HP Quincy QR-25 would have no problem meeting your CFM requirement. I think it's rated at about 20 CFM @ 125PSI.

Cheaper ones have lies plastered on them, so you have to take clues from the size and type of pump and motor.
 
a true 5 hp is huge . those pos that HF advertise are just weak 3 hp junk . the cfm ratings are done 2 way . what you have to have is a continuos cfm , not a blast of air then nothing. 90% of the problems i see are directly tied to poor air supply. orange peel , excessive film build, solvent pop and even delamination but people still buy those and try to make them work.
 
my 5 horse can not be moved intact . i'm a pretty big fella and pump or motor is about limit for me.
 
Crashtech...what a great, comprehensive article, thanks. Set me straight and made my eyes cross at the same time. Saw a post on YouTube where a guy made his own air drier from a condenser out of an old car radiator and a small air tank. What are the pros/cons of building your own compressor? My biggest fear would be that it would eventually explode on me, but what else?
 
There are several sources of information here on the forums about DIY chillers, the simplest of which consists of copper tubing in a bucket of cold water.

I'd pick a good used craigslist find over some low-end new unit any day. The problem is knowing what to look for, and being patient and vigilant enough to catch one when it pops up. Unless you can afford $2000+, keep on the lookout for a good used compressor. Look hard enough, and you may even find a pump here, a motor there, and one or more may have a good tank. This can be hard of you don't know what you are looking for, but generally if it is very heavy, and made in the USA, you probably scored. If you mix and match, you'll have to know the optimum RPM for the pump at the given HP of the motor, and buy the right size pulley accordingly. Of course the major drawback is that you will buy something broken. The best thing would probably be to find one that is all together and working.

You'll want to avoid the little motors that run at ~3450RPM or so. Find a setup with a motor in the ~1750RPM range. Those will be the ones that actually live up to their HP claims, and have the grunt to turn a beast pump at low RPM for quiet longevity.
 
I called...is there any chance I could run that on 230V in my garage? Found Eaton and Curtis 7.5HP/80 gal units. Any opinions, and what is the difference between an Eaton V4 compressor and the regular one (other than 300lbs and $300 dollars)?
 
crashtech;29862 said:
I was browsing craigslist in your area of the country and saw a bunch of junk, except for this big bad mamba-jamba that is TOTAL overkill for you, but man, that is a LOT of compressor for the price!

http://batonrouge.craigslist.org/tls/3924063943.html
Click to expand...

That 20 hp motor will make the power meter turn!

A motor of that hp is going to most likely be 3 phase and a darn good chance it is 480volt. If it isn't worn out and the tank isn't rotten it would be an awesome buy IF you had the power available to run it.

eb0248;29863 said:
I called...is there any chance I could run that on 230V in my garage? Found Eaton and Curtis 7.5HP/80 gal units. Any opinions, and what is the difference between an Eaton V4 compressor and the regular one (other than 300lbs and $300 dollars)?
Click to expand...

The 7.5 hp 240v 1ph most likely will require at least a 50 amp and preferably a 60 amp circuit.


When I am ready for a new compressor next spring I am considering this : http://oemaircompressor.com/castair-air-compressor/I718VC2.aspx. Can be found for $2400.

Castair Compressors: http://www.castair.net/industrial-air-compressors.html
 
Yeah, I just just kinda kidding about that big one. It might be 480V for all I know, and is surely 3 phase. Not really residential stuff, but wow, I would love to have it for my shop! Even if you had to buy a new tank, it's worth the money.

I'm pretty sure the Eatons are Chinese made, but I know nothing about the Curtis. Really what you need is more detailed information. A quick way to tell if the compressor is a serious piece is if the motor is ~1750RPM. The 3450RPM motors are too small, and try to make up for their deficiency by turning faster. Even with a tiny pulley, they will run a pump at 1200 or so RPM, which is too fast, and takes a small cheap easy to turn pump to go that fast. This gets you some CFM (for a while) but not even really enough to paint something big.

^ I see SOF beat me to it! :)
 
Thanks for all the ongoing help from all. At work, surfing when I can. My Vaper gun kit came in the mail today, now all I need is everything else, and the time to actually get the hang of spraying, let alone maintenance of the equipment. Kinda OCD with my stuff. Could afford new, but would like to find something used for much less. Too many other things to do with the money...son starts kindergarten in a week. I'm still looking.
 
I guess the looking/waiting paid off, found 2 Champion 7.5hp/80 gal units, both with magnetic starters and aftercoolers, $800 for both. Work fine, now if they don't fall off the truck getting to me. Thanks again for all the help/advice.
 
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