Another homebrew air compressor

DHS · Apr 5, 2009

Here is another homebrew air compressor. The compressor is a old Frigidaire refrigerator compressor that use to use sulfur dioxide. The tank is a 20lb propane. It is silent and slow but works great for occasional cleaning and such.

Mezzanine · Apr 5, 2009

Awesome. Really scary, but awesome.

What pressure do you run that up to?

DHS · Apr 5, 2009

Compressor comes on a 90 and off at 125. It easily goes much higher.

Mezzanine · Apr 5, 2009

Can't say I blame you! Does the tank have any pressure rating on it? It is pretty crusty looking, so I am not sure I would trust it anyway... Just tuck that thing away in a closet, or behind something solid, and use 'er till she blows. :spit:

Scary, but I still think it is pretty cool. :beer:

DHS · Apr 5, 2009

I am not sure of its pressure rating but I am sure it is enough.
The tank looks older and crustier than it really is. I keep this compressor out of the way and drain the tank daily. I

At a temperature of 70° F, propane's vapor pressure is 124 PSI.
At a temperature of 162° F, propane's vapor pressure is 390 PSI
I pulled this off of another website.

e-tek · Apr 5, 2009

This is one of the coolest items I've seen yet here! I like making things/tools that are useful in the shop and that's a beauty!! Nice work.

Torque1st · Apr 5, 2009

A pressure tank for compressed air can be tested by filling it completely with water and connecting it to a good pressure gage with a "T" to a grease fitting. Use a manual lever type grease gun to raise the pressure to twice the system working pressure, or as far as you get towards that figure before something ruptures... Wear appropriate safety glasses and a face shield. Make sure there is VERY little air in the system. The air is what stores that compressed energy and makes for explosions. Do not attempt this if you are not comfortable with what you are doing.

DHS · Apr 5, 2009

I should of pressure tested it when I had it full of water, welding everything on. Should I pressure test it to like 150 or 175 that way it is higher that my working pressure? Thanks

Torque1st · Apr 5, 2009

DHS said:
I should of pressure tested it when I had it full of water, welding everything on. Should I pressure test it to like 150 or 175 that way it is higher that my working pressure? Thanks

If you are running it at the normal single stage compressor working pressure of 125PSI then pressure test to 250PSI.

kbs2244 · Apr 5, 2009

I think the compressor will stall befor he gets to a too high pressure.
I do like those legs!
From an old bath tub?

DHS · Apr 5, 2009

I am a junkaholic and I probably got the legs at a yard sale or flea market not sure what they fit just thought they were cool.

Charles (in GA) · Apr 5, 2009

Probably old stove legs.

I have a Kelvinator sulfur dioxide compressor That I use for an air conditioner system vacuum pump, and it works fine. Was given the pump and its original mounting base minus the motor, I installed a 1/4 hp motor from a old Craftsman diaphragm air compressor, and have use it for probably 30 years now.

Charles

Torque1st · Apr 5, 2009

kbs2244 said:
I think the compressor will stall befor he gets to a too high pressure.

The reason for the 2X pressure test is so that a tiny amount of rust or corrosion forming somewhere inside or outside of the tank while in service does not weaken the tank sufficiently to cause the tank to explode. The welds can also weaken the tank and it must be tested. Tanks must be periodically pressure tested to maintain that 2X safety margin since they are subject to damage and corrosion. The safety valve is designed to prevent pressure from exceeding the working pressure of the tank.

If someone really wants to get technical they can look up the ASME pressure vessel testing standards. Actual certified testing is available in many areas for $$$. They would probably flunk the tank on appearance or for the welds tho.

Notice the jagged steel in the picture above and imagine pieces like that flying around your shop when you, the wife, the kids, the neighbor, or your buddies are out there.

pipehack · Sep 19, 2012

So, what you're saying is that you welded those legs on there..? Can I take an insurance policy out on you?

numbah9 · Sep 19, 2012

That air filter has gotta be worth +20hp!

DekeT · Sep 19, 2012

Torque1st said:
A pressure tank for compressed air can be tested by filling it completely with water and connecting it to a good pressure gage with a "T" to a grease fitting. Use a manual lever type grease gun to raise the pressure to twice the system working pressure, or as far as you get towards that figure before something ruptures... Wear appropriate safety glasses and a face shield. Make sure there is VERY little air in the system. The air is what stores that compressed energy and makes for explosions. Do not attempt this if you are not comfortable with what you are doing.

Could you fill the grease gun with water instead of grease to do this?

BMB · Sep 19, 2012

Almost has a steampunk-ish look to it.

I could see making a pigs head and tail for it too.
Maybe put a when pig's fly sign on it. :lol:

zip95864 · Sep 20, 2012

pipehack said:
So, what you're saying is that you welded those legs on there..? Can I take an insurance policy out on you?

hahaha

AZ Pete · Sep 20, 2012

The legs look like they are off of "Pot Belly" stove to me.

Looks cool!

Professur · Sep 20, 2012

Hydrotesting a tank costs peanuts, and there's certainly somewhere local to you that does it. I get my compressor tank done by the same guy that does my CO2 welding gas refills. Drop it off in the morning, pick it up at night on the way home ... sleep well.

Another homebrew air compressor

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