# Just got a new/used air compressor. Was this a mistake?



## Gamble

So I have a 12gallon vertical 1hp craftsman air compressor however it just doens't have enough volume for me and takes a while to fill up. I just got a HF sandblast cabinet and this thing can't keep up. Searched around my local CL and found this 









4hp 25 gallon craftsman air compressor. Looked at it and it worked but was missing the electrical cover. Figured that wasn't a big deal and I can make one or buy one. Talk price with the guy and ended up leaving with it for $100 and then bought his 1/2" airstream impact gun for another $15. 
Get it home and open the drain at the bottom. nothing comes out but I hear water splashing around so I take the valve off and can see the hole was blocked. use my screwdriver and out comes some water. Dirty Dirty water. And put my screw driver in there a few more times to work around the hole and it kep coming out black goo. This normal?

Oiless wasn't my first choice but the price was right and I needed 110v. So I find this video online




Same make/model etc, then look at my pic and you can see that mine has been changed around. The pressure switch is different, the regulator, the gauge, the lines etc. (I knew I had to add a gauge and that isn't a big deal)

Looked up sears parts website and the pressure switch is not available anymore. So what can I do? I can I buy a cheap $40 compressor and take the gauge,lines,pressure switch off of it and replace this one? I plan to use this a lot but it just looks like a hack job. What do you recommend or what would you do?
Also anyway to clean out the tank or is all that crap in there normal?

Sorry for making it so long. thanks in advance.


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## rhenning

That compressor won't be big enough for a sand blaster either. When I used to sand blast I connected my older 60 gallon vertical shop twin cylinder compressor to my 25 gallon 5 HP twin cylinder portable compressor and my gasoline powered one cylinder compressor and almost had emough air volume with the three running. With blasting you need huge volumes of air for it to work well. Roger


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## Gamble

Well it's better than my 12 gallon  And I don't have room or power for anything else so this will have to do. Besides it's not like I do anything big or major. Just little things that need cleaning up here or there.


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## cedgo

That doesn't look like a 25 gallon tank, but it is a picture.
Goo is not normal, water is. Keep the tank drained regularly.
As Mr. Roger says, it probably won't make enough air for a blast cabinet.
Almost any pressure switch will work. You can fabricate your own lines.
Make SURE you have a pressure relief valve installed. These thing can kill.


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## Gamble

Yep it has a relief installed. I'll throw the drain plug back on and try it out.


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## cedgo

I think you are probably in Fantsyland on that one.


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## pawon

*look at cubic feet PER MINUTE*

Hi, when comparing compressors, look at cubic feet per minute compressor capacity , not how many gallons the tank is.

Some manufacturers put a small compressor on a very big tank.. This is only usefull if you use compressed air in small. big bursts. But if you use a lot of air continuously (like blasting or for air grinders or even paint spraying), you need a big compressor,. not just a big tank.

See also this for lots of information: Air compressor buying guide, part 3: compressor specifications


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## ferry

pawon said:


> Hi, when comparing compressors, look at cubic feet per minute compressor capacity , not how many gallons the tank is.
> 
> Some manufacturers put a small compressor on a very big tank.. This is only usefull if you use compressed air in small. big bursts. But if you use a lot of air continuously (like blasting or for air grinders or even paint spraying), you need a big compressor,. not just a big tank.
> 
> See also this for lots of information: Air compressor buying guide, part 3: compressor specifications


Yes you are right for compressor, capacity is more important, not how many gallons the tank is.


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## FloridaGuy32

Gamble said:


> So I have a 12gallon vertical 1hp craftsman air compressor however it just doens't have enough volume for me and takes a while to fill up. I just got a HF sandblast cabinet and this thing can't keep up. Searched around my local CL and found this
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 4hp 25 gallon craftsman air compressor. Looked at it and it worked but was missing the electrical cover. Figured that wasn't a big deal and I can make one or buy one. Talk price with the guy and ended up leaving with it for $100 and then bought his 1/2" airstream impact gun for another $15.
> Get it home and open the drain at the bottom. nothing comes out but I hear water splashing around so I take the valve off and can see the hole was blocked. use my screwdriver and out comes some water. Dirty Dirty water. And put my screw driver in there a few more times to work around the hole and it kep coming out black goo. This normal?
> 
> Oiless wasn't my first choice but the price was right and I needed 110v. So I find this video online
> 
> 
> 
> 
> Same make/model etc, then look at my pic and you can see that mine has been changed around. The pressure switch is different, the regulator, the gauge, the lines etc. (I knew I had to add a gauge and that isn't a big deal)
> 
> Looked up sears parts website and the pressure switch is not available anymore. So what can I do? I can I buy a cheap $40 compressor and take the gauge,lines,pressure switch off of it and replace this one? I plan to use this a lot but it just looks like a hack job. What do you recommend or what would you do?
> Also anyway to clean out the tank or is all that crap in there normal?
> 
> Sorry for making it so long. thanks in advance.


No, "goo" is not normal, it most likely means it sat for a long time and/or was abused/neglected. If it doesn't come out thru some regular use and a few drains then you could try removing the inlet and check valve and pouring some mild or diluted degreaser in it and letting it sit for a bit, trying to swish it around often, then drain it and chase it with some distilled water and drain again. That should get it out, if not a little gunk at the bottom really should hurt anything outside of obstructing the drain. As said in a previous response, you always want to check the SCFM when shopping for compressors, especially when trying to power a specific tool. Pneumatic tools and compressors alike always have an SCFM rating, which ultimately determines it's usage/output. Pressure switches and regulators are essentially universal, but you should try to match the PSI rating to eliminate issues and ALWAYS make sure to have a blowout valve and that its set to blowout at or slightly below your systems "max air pressure" rating. Sprayers, blasters, blowers, grinders and such typically have a high SCFM and can be a hassle without a commercial setup. I have a 29g 2hp, 20g 4hp and a 8g 2hp that I have to connect to run in unison just to run some of my equipment, which is fine as long as you take into account each machines "max air pressure" keeping the highest rated machine as the primary and if need be use its regulator to reduce the pressure to below the max psi of the secondary to prevent triggering the blowout valve (or worse). I'm rambling.....I hope any of this helps and good luck to you.

Just realized this is a 9 year old post so I'm sure it was just a pointless ramble on my end...Who knows, maybe someone else may find some use out of this some day 😅😂🤣


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