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ebinmaine

Air compressor questions, advice?

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So let's just put this right out front that I'm trying to be cheap.

 

I can buy a pancake style compressor for a hundred bucks or less all day long but can't find a decent usable higher CFM compressor for less than 225 to 250.

 

I have a pancake style compressor that only puts out about half of the CFM that I really need on a regular basis.

I also have a 30 or 40 gallon empty tank. Maybe bigger?

I realize that combining the two will increase my Reserve but not increase my CFM capability.

My question is - can I add another pancake style compressor into the big empty tank and actually increase my CFM capacity?

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If your sand blasting, you're wasting your time fiddiling around with storage tanks and those little pancakes. What are you trying to accomplish? 

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If you are seeking a short duration high volume source of compressed air that would do it, but then you would have to take a long break while it recovered.   :icecream:

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Depending on what you are wanting to do, you just may have to "bite the bullet" and get a real air compressor!

My wife bought me a HF blast cabinet a few years ago because she said (we) needed one. I agreed with her and after she bought it and we put it together she asked why I wasn't using it.

I explained the small compressor I had wouldn't create enough air volume and I needed a BIGGER compressor.

She said, "If I  would have known you were going to need a $1000 air compressor, I wouldn't have bought the blast cabinet"!

I said, we needed the bigger air compressor any way!

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53 minutes ago, KC9KAS said:

"If I  would have known you were going to need a $1000 air compressor, I wouldn't have bought the blast cabinet"!

 

It appears to me that she will be thrilled when you buy a $500 compressor, as she implied permission for a $1,000.00 unit.  That would be my story anyway.....:ychain:

2 hours ago, ebinmaine said:

I add another pancake style compressor into the big empty tank and actually increase my CFM capacity?

I don't think you will be at all impressed with the performance of 2 pancake compressors in series.

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2 hours ago, squonk said:

If your sand blasting, you're wasting your time fiddiling around with storage tanks and those little pancakes. What are you trying to accomplish? 

As of now... air chisel and impact.

I will be buying a handheld blaster at some point though.

2 hours ago, 953 nut said:

If you are seeking a short duration high volume source of compressed air that would do it, but then you would have to take a long break while it recovered.   :icecream:

Yeah that's what I was wondering....

Work, work, work... Nap, nap, nap....Repeat.

1 hour ago, Texas Todd said:

I don't think you will be at all impressed with the performance of 2 pancake compressors in series.

Methinks I'll have to just get a bigg'un....

 

Maybe I can convince my Honey I can help her DO stuff with it...

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9 hours ago, ebinmaine said:

 

Methinks I'll have to just get a bigg'un....

 

 

 

Yessir .

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In all honesty - pancakes can barely handle an air nailer let alone an impact or air chisel and forget any type of blaster . To do it right and not kill a compressor doing even minor tasks it requires around 23cfm to handle your needs . Look around for an old Champion or similar 2-stage - those can run for a lifetime and most of the older ones can easily be overhauled . It's tough to find a decent pump made today as well as those older pumps were built - it's nothing to see some made in the '60s that are still in service with no blow-by or oil showing up in the tank . My old SpeedAire is from the late 70s/80s era and still going strong today . Processed over 1300lbs of coal slag through the 90lb blasting pot in the last week or so doing my utility trailer , plus other duties like running a medium barrel air hammer and needle scaler . System went down for 3 days over the Holiday weekend due to a blown starter capacitor in the old 5hp motor since no one had a 1070MFD one in stock - replaced all 3 to prevent further issues as I run this thing hard and hot at times - all good now .

 

I scored this old dumb thing years ago out of a defunct car wash - for free . It was a 3ph motor , but a buddy at work had a Farm duty 5hp single phase motor he was tired of tripping over - 12 pack of beer later it was mine , albeit stupid heavy compared to the 3ph . Look around for one that is a continuous duty 2 stage and at least 23cfm - you'll never regret it .

 

Sarge

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Trying to answer your question first and your needs later, your two compressors will indeed equal your combined CFM ratings (though watch for CFMs at what PSI).  Though I doubt that even combined they will amount to much for sandblasting.

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11 hours ago, DennisThornton said:

Though I doubt that even combined they will amount to much for sandblasting.

Yeah...

Something I didn't realize until yesterday is that it's recommended to have a compressor of 1.5 Times the needed cfm at Minimum. 

I have a big old tank to use already so I'll see what I can do to get an older model compr for it.

 

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I had a big industrial 5hp that could run a pressure blaster with an 1/8" nozzle.  I would have been disappointed with anything less and would have preferred much more.  However, even short blast times are great for small jobs, cleaning small parts or rust spots but you'll be aggravated trying to blast a whole panel or frame and be looking for a bigger compressor.  Look for CFMs!  Volume!  Not just pressure or tank size.  Tank size is unimportant when blasting since your compressor will most likely be running continuously. 

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22 minutes ago, DennisThornton said:

compressor will most likely be running continuously.

That is what brought this up in the first place.

The duty cycle of my current compressor is 50%, so I understand it should be running no more than 50% of the time. If I did the math right, I'd have to connect 4 or more of these to make it work... Not happening.

I'll look for an old industrial grade one.

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5 minutes ago, ebinmaine said:

That is what brought this up in the first place.

The duty cycle of my current compressor is 50%, so I understand it should be running no more than 50% of the time. If I did the math right, I'd have to connect 4 or more of these to make it work... Not happening.

I'll look for an old industrial grade one.

 

Good idea.

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That is a good point - the largest nozzle size I can run is a 5/32" , just slightly over 1/8" bore . At that larger size , even with two tanks to hold the extra volume it runs my pump nearly continuously and gets it quite hot . The pump is built to do this but I prefer to avoid it due to it's age . Using the additional 60 gallon tank helps cool the air further and take some of the heat out of the system as well as provide a place to get rid of the water condensate . Filter/regulator at the 80gal pump unit , another one outside where it exits the building and I still get water in the 60 gallon tank . I run 1/2" hoses outside with no less then 3/8"NPT fittings on each hose . Any restrictions create heat back to the pump and that's not a good thing as it also hurts overall volume .

 

I know cost is a big factor in buying equipment - that's why a lot of the time anything I buy in the bigger stuff is used . Takes time to find a decent deal but well worth the effort . With some mechanical/electrical skills it's not too hard to find a very heavy duty compressor and never regret later not having a large enough one to do the job . One thing to consider is the electrical requirements of bigger equipment - you're going to need a 220v circuit capable of 50-60amps at load/startup . Also , that pump is best located near the electrical panel - otherwise you'll need a sub box and some really heavy 6ga or better cable to feed it , and forget long runs back to the main panel as it will overload/overheat the breaker . My unit sits right next to the 100amp panel in the basement - no fun getting it down there but that's where my shop is for now .

 

Just ran a statewide quick search in Maine  - there's a few I'd like to own myself right now on CL...

 

https://maine.craigslist.org/for/d/air-compressor/6295649377.html

https://maine.craigslist.org/tls/d/air-compressor/6292961925.html

 

That big Champion was built in my hometown of Princeton, Illinois - would probably run for another 30yrs easily . Champion units will demand more money - but well worth the price . Having the Gardner-Denver label on it tells me it was built in the last 8yrs . Not the best ones they made , but still a great unit in comparison to most of the junk sold now .

 

Sarge

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When my dads shop shut down I got a bunch of tools. Among them were a 60 gallon speedaire compressor. We put a new 5hp 220v motor on it from granger. That was about a year before the shop closed. It sat in my shed for 5 years and has been in my garage in the new house for 3 months. Just waitin on my cousin to wire me up a 220 drop!

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One of the guys at work does a lot of home mechanic type stuff and he has a neat set-up I'm now half-way to duplicating.

He uses 2 compressors that are both in the 6 - 8 CFM range all plumbed in together.

One is his main, the other kicks in at a lower pressure so its rarely on unless running a hungry tool.

 

I scored a very old and well-maintained Sears Roebuck unit. Replacement 4 HP 220V motor. Dude that had it bought a new model 'cause the drain plug left town on this one. 

I didn't really want to deal with 220 due to not having a plug but it looks like it won't be too hard or expensive to add one.

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I run a similar system. The gun I use requires 12 cfm. I have a 5 cfm 30 gal and an 8 cfm 20 gal piped to a 6 gal tank for my blast cabinet. It works but only if you are not in a hurry.  I will be changing the 5 cfm compressor to an 11 cfm before I use the blast cabinet again to speed up blasting time. 

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Those older Sears 2-stage compressors are worth hunting - a buddy of mine got one free and it turned out to be the fastest recovering small pump I've ever seen - it's been used to fill up to 120gal of reserve tanks to feed a set of not-kidding train horns , a full chorus to boot . Almost every one of those Sears is a light machinery green in color and the way the pump and air switch is designed it's very easy to adapt it to gas powered or other uses - just a very well made pump that builds air volume easily . We've put one on an older 3hp Briggs engine that I modified slightly to handle the load - works excellent . I have yet to find a set of honest specs on the pump they used and suspect due to it's shape it's a small Champion pump , which explains why they last forever....

 

Sarge

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Just went through the process to get a new air compressor. Had a Craftsman (Devilbis) 30 Gal. dry lube wheel barrel style Air Comp think it put out 7 CFM @ 90 psi which got me by for over 30 years. Had to rebuild the compressor a couple of years ago but finally decided to replace as it got way too noisy.  Need a compressor to power aircraft rivet guns, grinders, sandblast tools and needed a minimum of 10 CFM @ 90 PSI. The vertical units offer large tanks reducing duty cycles for longer duration tasks wanted to stay with the wheel barrel style for ease of portability. After many hours of research decided on a Campbel Hausfeld VT6271 - 26 Gal., HD Cast Iron Comp, oil lubricated and puts out 10.5 CFM @ 90 PSI.

 

They're priced fairly reasonable (500 - 750.00 range) from sources online but shipping costs was an additional 125.00 + which put them out of reach. Home Depot sells them if you're lucky enough to find one in stock. Had a welder scheduled to come over to install body mount brackets on a Corvette I'm working on and needed something fairly quick. While searching the web for the best price found they are available through True Value online for 549.99 with free delivery to  your local True Value store. Never considered looking at True Value online but was pleasantly surprised to learn they offer free shipping on anything purchased online for  pick up at their stores.

 

Overall a very capable compressor. The duty cycle is a bit frequent when grinding/sand blasting but happy with it so far.

 

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7 hours ago, Sarge said:

Those older Sears 2-stage compressors are worth hunting - a buddy of mine got one free and it turned out to be the fastest recovering small pump I've ever seen - it's been used to fill up to 120gal of reserve tanks to feed a set of not-kidding train horns , a full chorus to boot . Almost every one of those Sears is a light machinery green in color and the way the pump and air switch is designed it's very easy to adapt it to gas powered or other uses - just a very well made pump that builds air volume easily . We've put one on an older 3hp Briggs engine that I modified slightly to handle the load - works excellent . I have yet to find a set of honest specs on the pump they used and suspect due to it's shape it's a small Champion pump , which explains why they last forever....

 

Sarge

What are the train horns used for?  I got a dual trumpet boat horn that rattles your tooth fillings pretty good! :)

 

The key to getting the moisture out of the lines is to run steel lines. The cold steel will condense the moisture. For take offs install risers then pipe down. The moisture will want to stay in the lower part of the pipe and not travel up. Have a water separator at the outlet and a drain at the end of the run as well as below the separator. :banana-wrench:

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22 hours ago, Sarge said:

it turned out to be the fastest recovering small pump I've ever see

That was one of the things that really impressed the guy that had it. 

 

His not being able to to (or not wanting to):dunno: find a tank is great for me.

 

22 hours ago, Sarge said:

Almost every one of those Sears is a light machinery green in color

I've seen those in the past but this one is red and has been for as long as the PO knew (2 or 3 decades at least)

I'll post a pic or 2 later.:wwp:

I'm curious to know who may have made it.

 

22 hours ago, Sarge said:

We've put one on an older 3hp Briggs engine that I modified slightly to handle the load - works excellent

I'm likely going to leave it 220V for now but have seriously considered using a 1976 B & S 8 horse on it in the future... For no real reason other than tinkering.

 

15 hours ago, squonk said:

is to run steel lines.

It's going to stay as flex rubber for now but I really appreciate the info because in (hopefully) 2 or 3 years the set-up will be hard piped into the barn we don't have yet.

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The 8hp Briggs will pull that pump fine . I'm almost certain Champion built the pumps but who really knows ?

 

My compressor sits near the panel due to it's startup of nearly 70 amps @230v . All the lines in the basement are high pressure PVC with several vertical drops w/valves to drain them on occasion . The whole issue is the pump sucking moisture out of an old basement in a heavily built old brick building . Not to mention I'm drawing around 25-27cfm at times when I'm blasting - that old SpeedAire gets really hot , even with synthetic Royal Purple Recip100 in it . I honestly need a rotary unit outside with an engine drive - but haven't found a good one used that isn't already blowing oil and shot - most are being sold by construction companies instead of being rebuilt as they can use the equipment writeoff on taxes . The last low hour unit I found went north of $5k - which was still fair as it was a 180cfm unit in excellent condition .

 

The horns being fed by the old Sears and a small Englo style wheel barrow compressor are on this - built by the Santa Fe railroad in 1948 - a friend of mine owns it and I worked on it's restoration/upgrades . We primarily use it for parades and leading the yearly Toys For Tots parade in Chicago every December for the last 10yrs - the largest motorcycle parade in the world .

http://www.mytrain.com/trainschedule.html

 

The first year after the restoration/paint we took it with a nearly bare interior (in the winter , not kidding) to the World Of Wheels auto show in McCormick Place , Chicago - it won it's class , I'm the nut on the left -

show2.jpg

 

Nothing comes close to seeing 50,000 motorcycles in December on Western Avenue early Sunday morning - we lead the Parade ahead of the tiers of bikes and lead them to the Marine Corps Reserve stations...horns blaring wide open to wake the City ....

 

2015parade1.jpg

 

The thing is a rare piece of railroad history and few know about it . Doing an off frame resto with a crane was certainly a bit different - although I was a lot younger back then . It's nearly impossible to put a true value on it - it's the only one ever made....

 

Sarge

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Cool! I Glad it's for a good cause instead of that annoying train horn at Buffalo Bills home games! :shock:

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