Air compressor question

[travler_79]

Hi all.

I've been a reader of this site for several months so i figured it was time to post my first question. I'm wanting to update my air compressor. I want something big enough to handle sand blasting. I was thinking of a two stage with an 80 tank but they are a little out of my price range. I've found a new Eaton 3 cyl 2 stage pump rated at 18 CFM at 100 PSI. It requires a 5 HP motor which i have laying around. The cost including the motor pulley and shipping will be about $450. For air storage i was thinking of useing 3 100# propane cylinders mounted upside down on the wall. I'd plumb all three together with a valve between the first and second so in most cases i'd only have to charge the first tank but be able to have the extra space with a turn of the valve. I was also thinking of plumbing them together with a cross instead of a T and under each one have a 6 inch ****** and a valve at the bottom for a water trap, along with a water trap and filter before the hose real. Any thoughts on this set up? Is this pump going to suit my needs? Are three tanks for air storage over kill? I'm thinking of useing three cuz they too are laying around. Any thoughts or suggestions are greatly appreciated. thanks

 

[rickairmedic]

Travler how big is your current tank and why couldnt you just mount the new compressor pump and motor on top of it . I would say if its a 60 galon thats the way I would go . I would also check out craigslist . My neighbor just picked up a sweet 2 stage 80 gallon unit for $300.00 last week. I tried to talk him into trading as he will never use that much compressor . I couldnt beliieve how quiet it was compared to mine and mine is a standard belt driven .

Rick

 

[tcianci]

Nice idea but do your numbers first.. Is the motor rated for the duty cycle that the compresser use will require? Do you have the pressure switch, relief valve and other plumbing that it will take to fabricate this set up? What is the condition of the propane tanks? Are you bolting potential explosives to your wall. Is the motor rpm compatible with the required rpm to get the correct CFM from the pump? Also remember that you need sheaves and belts, intake filter etc. The rated cfm of the pump is the displacement, not the delivery. The delivrey is .based on the displacement X volumeteric efficeincy so be sure this set up will meet your needs. A rough guess is that if you pay yourself nothing for your time, once you buy all the junk you need to put it together you will be about 300 bucks shy of a shiny new warranteed unit. Just my 2 cents

 

[twostory]

I agree with what "tcianci" said. I have a 60 gallon tank with a heavy duty pump that I got for next to nothing. I just need to buy a motor and pully. Well the motor is $300+ new.

I found a Saylor Bealle (5hp, 18cfm) on craigslist for $600. With my limited useage, it will last for a long time.

Either look for a good used compressor or find a compressor tank missing either the pump /or/ motor.

Non-working compressors are not worth much, so the price is low.

If you were near Atlanta, I would give you are great deal on a compressor (tank & 2 stage pump) that needs a new motor (5hp size) and pully.

 

[tdoty]

Those Eaton pumps are darn good units! A couple of friends have them, and have nothing but good things to say about the performance.

Tim D.

 

[travler_79]

The tank i have now is a dinky little 15 or 20 gallon 2 wheeled jobby. Looking for more storage. The propane tanks i'm thinking of useing have been stored in a shed since they where emptied about 5 years ago. Just need to scrape the bird **** off, sand them a little, and repaint 'em "sunrise red" (to match everything else). I emailed the specs off of my motor to the guy selling the pump and he told me the motor would work fine. He said i needed a 6 in. pulley though and that sounded a little bit too big to me. I checked the compressor at the shop where i work which also has a 5 hp motor but a single stage pump and it has a 4 inch (app.) pulley. But the RPMs are 3450 vs. the 1725 that my motor is rated at. So i guess it stands to reason that if i'm turning half the RPMs i need a bigger pulley.

My time in my garage is worth nothing except to me and i agree that by the time i get my contraption all cobbeled together i'll only be a couple bucks short of paying for a new one but..... One thing me and my little mind get off on doing is coming up with new ways to reinvent the wheel.

I have been watching ebay but kinda forgot about craigslist. Think i'll check that now.

Thanks for the input so far!

 

[krcotter]

My neighbor daisy-chained 3 100 gallon propane tanks above his garage, the system works well with a few water collection valves. For sandblasting the IR 4 cylinder towed unit comes out (approx 140 cfm). It doesn't have much of a tank, so it just runs while we blast. We can run two blaster simultaneously though. My goal is to find and restore a Leroi Compressor Tractor some day!

 

[RECox286]

My shop has 2 old (ancient) compressors, but when I want to blast

I also have a tow behind. It's a Smith Monoblock, rated for 110 scfm

@ 90 psi. Does everything I want it to, even when we are not at home.

Uncle Bob