Air Compressor Recommendation

Balvar24 · Post by **Balvar24** » Fri Jun 17, 2011 2:11 pm

http://tinyurl.com/3or54kb

Paint time is nearing and this is on sale. Opinions?

I took the liberty of converting your long (1154 character) URL to the 19 character URL above. This is easy to do at the Tiny URL web site and is a free service. http://tinyurl.com/

Wes K Moderator

RICKG · Post by **RICKG** » Fri Jun 17, 2011 3:12 pm

Before you buy be sure to check Harbor Freight. They have a
good selection of compressors on the floor. They periodically
run promotions on them also. Think beyond the paint job at hand,
will you be sandblasting, running air tools, etc? Consider what else
you'll be using it for in the long run before making your decision.
It's a big tool purchase-make sure it'll tackle any job you assign it.

RimfireJim · Post by **RimfireJim** » Fri Jun 17, 2011 3:29 pm

I don't have that model, but I do have a similar Porter-Cable compressor that has about 80% of the rated output of the one you're looking at, and it is plenty of compressor for home hobby auto painting. The blast cabinet keeps it busy, but it does the job. I've painted a car before with a 1 HP, 20 gal. portable compressor and got the job done, but no way could it keep up with a blast cabinet. Most handheld air tools are not a problem with either, because you don't use them that long in one stretch, a sander being one exception.
I notice the specs on the Kobalt say 15 amps at 240V. That sounds kind of low to me for the output listed. Mass market compressor manufacturers are notorious for exaggerating their performance claims (as are dust collector mfrs.). See if you can find a review that made actual performance measurements.

Post by **wesk** » Fri Jun 17, 2011 9:23 pm

This is the subject of Balvar's post.

Kobalt 3.7 HP 60-Gallon 155 PSI Electric Air Compressor
Item #: 221565 | Model #:LLA3706056

3.7 HP 60-Gallon 155 PSI Electric Air Compressor

Cast iron, twin cylinder, oil-lubricated pump features one-piece cast iron crankcase, thermally stable cast iron cylinder body, aluminum head and machined cast iron valve plate, automotive style ball bearings, and durable stainless steel reed valves
Heavy duty induction motor for maximum performance and efficiency, 208-240 volt
Large capacity, 60-gallon ASME vertical tank provides more air for longer tool run times on air tools such as ratchets, impacts, spray guns, hammers, etc
155 PSI max pressure, 13.4 SCFM @ 40 PSI, 11.5 SCFM @ 90 PSI , 3.7 running HP

Balvar24 · Post by **Balvar24** » Mon Jun 20, 2011 6:41 am

Yeah, I've been keeping an eye on Harbor Freight. They've got a similar model with similar motor on sale this month for $399. I've been looking for a while. Most of the motors in this size machine are rated a 15 amps where as the next size up machines are all rated closer to 17-19. The motor horsepower on this size are all rated as "SPCL" (special). I believe most are probably 1 1/2 HP. The next size up machine jumps to around a $700-$800 price point depending on manufacturer. I've been looking for a while. I'll probably end up with a small benchtop blast cabinet before its all said and done.

What kind of compressor is everyone else, especially you guys tackling frame-off's, running? Motor size? Tank size? Capacity?

I'm not married to any one manufacturer at this point. And, it would be good info for some of us newbs.

major519 · Post by **major519** » Mon Jun 20, 2011 7:04 am

Here's my take...
I currently belong to an auto club where we have our own building, tools etc.
We have a 5hp compressor to run the shop. While it is OK for air tools used sporadically, it just doesn't quite keep up with air sanders, sandblast pots or the blast cabinet.
Sandblasting with an inssufficient compressor is like peeing in the wind! It is a waste of resources as the sand doesn't perform as it should.
It is a balance of job requirement vs. price in the longrun.
I believe bigger is better. Personally, when I build my shop, I am going with one of the old school comps with cast iron body instead of the cheap offshore aluminum junk. At least they are re-buildable and have great service life.

RICKG · Post by **RICKG** » Mon Jun 20, 2011 8:12 am

I got the harbor freight unit with the specs similar to the one
you're looking at-yep it was about 400 bucks. You'll be in about
another 100 bucks by the time you hardwire it 240V, build an
air manifold w/fittings etc. I built my manifold with 2 sides-1 at full tank pressure for blasting etc, 1 with a pressure regulator for fine tuning
the pressure to the paint gun. A sandblaster will keep this unit busy,
but it's adequate for random blasting jobs with a pot or cabinet.
When i blasted my frame i hired a guy with a truck mount unit-he
came to me and was done in about 2hr-well worth the expense.

Balvar24 · Post by **Balvar24** » Mon Jun 20, 2011 9:03 am

RICKG wrote:I got the harbor freight unit with the specs similar to the one
you're looking at-yep it was about 400 bucks. You'll be in about
another 100 bucks by the time you hardwire it 240V, build an
air manifold w/fittings etc. I built my manifold with 2 sides-1 at full tank pressure for blasting etc, 1 with a pressure regulator for fine tuning
the pressure to the paint gun. A sandblaster will keep this unit busy,
but it's adequate for random blasting jobs with a pot or cabinet.
When i blasted my frame i hired a guy with a truck mount unit-he
came to me and was done in about 2hr-well worth the expense.

Thanks. This is the set-up I envision. Large blasting jobs are just not in my future. There is a local guy who can take care of this for me. I've got the wire already pulled. Are you spraying HVLP? How noisy is the machine? I'm thinking about putting it in my basement.

RICKG · Post by **RICKG** » Mon Jun 20, 2011 9:27 am

I USE BOTH HLVP AND GRAVITY FEED GUNS DEPENDING ON MY NEEDS
AT THE TIME. AS FAR AS NOISE-COMPARED TO ONE OF THOSE DIRECT
DRIVE UNITS IT PURRS. BUT IF YOU PUT IT IN THE BASEMENT THE
MISSUS WILL DEFINATELY HAVE SOMETHING TO SAY ABOUT IT

AND REMEMBER WHAT MAJOR519 SAID-IT WONT KEEP UP WITH
HEAVY AIR TOOLS-SANDERS AND SUCH.. IF I HAD IT TO DO ALL
OVER AGAIN (AND THE CASH) I'D GO FOR MORE COMPRESSOR.

Balvar24 · Post by **Balvar24** » Mon Jun 20, 2011 9:31 am

RICKG wrote:I USE BOTH HLVP AND GRAVITY FEED GUNS DEPENDING ON MY NEEDS
AT THE TIME. AS FAR AS NOISE-COMPARED TO ONE OF THOSE DIRECT
DRIVE UNITS IT PURRS. BUT IF YOU PUT IT IN THE BASEMENT THE
MISSUS WILL DEFINATELY HAVE SOMETHING TO SAY ABOUT IT

Yeah, but will I be able to hear her over the air compressor?

madmike · Post by **madmike** » Mon Jun 20, 2011 10:06 am

I had one of the 5 hp single stage units for a few years and had it in the same garage as the sand blaster. Big mistake because mine ran at about 3000 rpm and are really noisy. You need ear protection. Besides that, the tank size matters depending on what you do. Your recovery rate tells the story about single stage vs two stage ( where one of the cylinders is larger than the other) and the two stage runs at about 1800 rpm with much less noise. I bought a 5 hp Quincy two stage , 60 gallon unit, and it is recovers 15-17 cfm at 40 lbs and 12 cfm at 90 with a 175 lb max. This will keep up with a sand blast cabinet and not drive you nuts doing it.

When I bought this unit, the dealer (air compressors is their business) recommended to run the unit at 150 lbs pressure before cycling, rather than the preset 175. He said the lower pressure will add years to the life of the unit. That is what I have done and for ten years it has been trouble free.

Another thing, you need a water drain nearby and a water filter in line to pick up condensation. Otherwise you get water in your paint, your power tools and on freshly blasted metal.

Lastly, you should know the start up amperage on the unit involved because they start at a much higher amperage than they run. Mine pulls 29 amps to start and runs on 22 amps. The single stage will be less but you don't want to blow your wife's TV circuit breaker when she is watching daytime soaps. These units get expensive but if you will have more Jeeps in your future, they are well worth it and ultimately pay for themselves.

TP Sandblasting has a good schematic on how to route air lines to minimize moisture.

toojeeps · Post by **toojeeps** » Mon Jun 27, 2011 11:05 am

I purchased a Ingersoll and Rand from Tractor Supply $1199.00 on sale. 5hp motor, two stage compressor, 80 gallon tank. I beiieve it is rated at 15.9 at 90psi. No regrets! I should have done it years ago. It keeps up with my twenty gallon reservior sand blaster with no problem.

Balvar24 · Post by **Balvar24** » Mon Jun 27, 2011 2:00 pm

Seems I'm all but determined to get the Harbor Freight 60 Gallon $400 (on sale) machine. Looks to be US made. I would like to have the bigger machine, but $800-$1000 is a lot of cake when I've got two engines in the machine shop. As long as this machine keeps up with my painting needs (JEEP), I think can compromise in some other areas.

Ranger · Post by **Ranger** » Mon Jun 27, 2011 4:23 pm

Before I say what I'm running, I'm going to beg you to not get a compressor from Harbor Freight. Long story short, I was painting my Mustang and the flywheel on the compressor blew up! They also shoot oil of the vent and get it on everything.

I'm running this

Got it from Lowes in '09, back then it cost $750 but I think it was on sale. This is a great machine, best one my dad and I ever owned. I think it puts out 16CFM @90 psi, it will run my 110lb pressurized sandblaster with ease.

Its expensive, but it's worth it.

RimfireJim · Post by **RimfireJim** » Mon Jun 27, 2011 4:29 pm

Balvar24 wrote:Seems I'm all but determined to get the Harbor Freight 60 Gallon $400 (on sale) machine. Looks to be US made. I would like to have the bigger machine, but $800-$1000 is a lot of cake when I've got two engines in the machine shop. As long as this machine keeps up with my painting needs (JEEP), I think can compromise in some other areas.

Seriously? If it is from HF, it's hard to imagine it being made in the U.S. Is it one of their "U.S. General Air Superiority" compressors? If so, that's just another HF brand label like "Central Pneumatic" (not to be confused with Chicago Pneumatic) and "Chicago Electric". I found one reference on the Web that stated the HF's U.S. General and Lowe's Kobalt brands were made by the same supplier. I don't know if there is any truth in that.

Do you have the air flow specs of your spray gun? Have you compared them to the specs of the compressor(s) you are considering? Keep in mind that for hobby work you aren't typically spraying continuously, which gives the compressor some time to catch up.

Just as important as having an adequate compressor is using adequately sized piping and air hoses to minimize pressure drop between the compressor and the tool. If you run rigid piping to distribute the air, don't forget to put a flex hose between the compressor and the piping. And don't use PVC for piping - it creates shrapnel if it bursts! I ran copper with sweated fittings for mine, but galvanized iron pipe is fine, too. As madmike mentioned, TP Tools has good info http://www.tptools.com/lp2/Tech_Notes.html, as does Sharpe Manufacturing http://www.sharpe1.com/sharpe/sharpe.nsf/Page/Support