I am in the market for a new air compressor. I currently have a Devilbiss 5HP 20 gallon. I know that it really isn't 5HP but that is what it is advertised as. I have been trying to do some sand blasting of my rear suspension parts with a small Harbor Freight sand blast cabinet. Even the small bench top blast cabinet is too much demand for this compressor. The compressor has been good over the years and has worked well with nail guns, air ratchets, impact guns, etc. but to do anything with serious air demand is too much for it. I think it puts out 8 CFM @ 90 psi. The specs on the blast cabinet call for 10 cfm @ 100 psi. I saw a 2 stage 60 gallon compressor @ Harbor Freight for $800.00. This is the only 2 stage compressor in this price range that I have seen. Everything else out there seems to jump up into the $1000.00 range. I really would like to spend a little less than $800.00 if I can, so as not to dip into my limited C3 parts budget. I have seen several single stage compressors, all 60 gallon tanks from around $500.00 to $680.00. The choices are Husky, Kobalt, Craftsman, Quincy, and Puma. I've read all kinds of reviews and they all seem mostly positive for each of them. They are all around 3.5 to 3.7 HP and put out roughly 11.0 to 11.5 cfm @ 90 psi. So what do you think? spend a little more and get the 2 stage or buy one of those single stage types if they are adequate and save a few hundred?

 

I had a 5 horse single stage compressor putting out 11 cfm @90. It was good for moderate sandblasting but the duty cycle was only 50% and for sandblasting it was running continuously and it had a relatively short life because I usually exceeded the duty cycle. I also had a 2 hp compressor putting out 6 cfm @ 90 and linking the two together provided adequate air for all sandblasting needs. Now have a single stage 7hp putting 30cfm @ 90 and it provides considerably more air than I need. I think you really want 18 cfm @90 to handle signficant sandlblasting such as a car frame.

 

I didn't take into account duty cycle. I'll have to read up on that. I am not sandblasting the frame. I am only using a small blast cabinet to clean up strut rods, half shafts, control arms, etc. I was going to sell off my current compressor but maybe I'll keep it and run it in parallel with the new one.

 

I think then probably 11.0 CFM @ 90 would do you if you're not going to exceed the duty cycle regularly. When I had my 2 hp and 5 hp hooked up together I sandblasted a frame and both were running continuously. I shouldn't really say my 30cfm provides considerably more air than I need, I haven't done any significant bodywork since we got it and I don't know what the duty cycle is on it but I think if I were sandblasting a frame it would only run half the time while doing it.

 

The Harbor Freight 2 stage compressor lists 15 CFM @ 90 psi, which is why I am strongly considering it. Is the duty cycle based on the same principle as a welding duty cycle?

 

Yes. If its a 50% duty cycle the compressor should be running a maximum of 1/2 hour out of every hour. When we were looking for a compressor after our 5 hp blew up we saw a few with a continuous duty cycle so those are out there too.

 

Also, keep in mind that if you decide to keep your old compressor and hook it together with your new one they're going to have slightly different cut in and cut out pressures so even though you'll have a lot of cfm potential one compressor is going to cut in before the other and you may find one compressor is running continuously or almost continuously and the other only cuts in occaisionally when you have very high demand.

 

Thanks that's good info.

 

Glad I could help.

 

I found mine on Craigslist. I paid $400.00 for a 5HP 60 gallon. It has been woking for a year with regular medium to heavy use. It runs my blast cabinet and cathes up under continuous uses. I use alot of air tools now that I am working on the frame and supplies plenty of air. Look at Craigslist, you may a good deal.

 

I bought a 60 gallon Husky from Home Depot. Twin cylinder motor and carries about 125 psi. It's got plenty of air for all my air tools and I'm sure it would handle your needs too. I believe it was just over $ 500 before taxes.

 

I see industrial grade compressors frequently on Craigslist. Many are from shops that are closing up and it is not uncommon to see a $2000 compressor in excellent condition selling for well under $1000. Before spending big money on a compressor however, you owe it to yourself to see where it is made. I noticed recently some 60 & 80 gallon "industrial grade" Ingersoll Rand compressors are being made in China.

Something I discovered regarding the duty cycle on piston type compressors is that you can easily extend the duty cycle by switching to a synthetic oil in the compressor. AmsOil sells a synthetic oil specifically for compressors (I suspect others do as well). It costs no more than their normal synthetic oil, but since it is designed for compressors, I chose it. Mine takes less than a quart of oil to fill it so it is a minor investment.

Previously after about 30 minutes of continuous operation of my 3hp-20gal compressor, I could actually smell it in the garage. I would just let it cool for another 30 minutes and then continue. The first time I used it after switching to synthetic oil, I realized after about 45 minutes I wasn't smelling it. I stopped working and went to check the compressor. Until I was almost on top of it I couldn't smell a thing and it wasn't nearly as warm as it would have been in the past.

Good luck... GUSTO

 

One key factor when sandblasting is the size of the compressor storage tank. I have an old 5 hp gas station compressor with a huge tank and been blasting for 30 years with it (nock on wood) .Are you using a sandblast cabinet or a pot type blaster ?
Wes

 

I purchased an 80 Gallon 2 stage compressor from HF about 5 years ago. It gets a lot of use and it has run flawlessly.

A suggestion. Before you purchase it, do a search for "Harbor Freight Coupons". I did this a couple weeks ago and got an additional 20% off my order - $150!!!!

 

Picked up this compressor at Lowes years ago and it's worked great. 60 gal,single stage. Its a little loud, but plenty of air for blasting. Painted 2 vettes with it, no problems.

 

I was going to pull the trigger on the Harbor Freight two stage compressor but they said that the 20% coupons could not be used on compressors. That would have put me at about 680.00 with tax out the door. I saw that 60 gallon single stage at Lowes for 500.00. I am leaning towards that one.

 

What's the cfm and duty cycle on them? Its better to have more air than you need rather than less than you need.

 

Wonder when HF changed that policy?

Good luck with your search.

 

Go as big as you can.

 

I run a craftsman professional 60 gallon. You can see the small cabinet I use as well.