Air compressor repair/upgrade

[Teikas Dad]

I've got a 25 or 30 year old Sears two cylinder/two stage 20 or 25 gallon air compressor that someone gave me for free. There's a pinhole in the bottom of the tank where it rusted through. The motor runs great and builds pressure quickly. All the piping is solid and the electric motor has no issues.

Compared to the oilless compressor that I have in my shop now the two cylinder compressor is almost silent when it's running so I'd really like to get it working properly again. I have to wear earmuffs or plugs in the shop whenever I turn on the oilless compressor.

I was going to weld the rusted spot figuring that would save the tank. But, I've been doing some research on the net and I quickly learned that it's a big No-No to weld a rusted compressor tank as they will usually go BOOM on you.

I've had no luck trying to track down a replacement tank. I saw a lot of posts on various websites where people were recommending unused propane tanks (once they're empty) as a replacement compressor tank. I've got two 20 gallon propane tanks sitting around unused that are in really good shape. Would it work connecting the two tank valves together with a hard plumbed T, then running the compressor line into the T.

Would that work? From what I could find out propane tanks can hold much higher pressures than air compressor tanks.

Figured before I blow up my shop or myself I'd check with you guys. There's a wealth of info on this forum and I don't think I'm the first one who's been trying to come up with a workable solution.

 

[swlman2]

I had to patch one once. i just cut out a section of pipe, that sortof matched the roll of the tank. i made the patch an inch bigger all the way around so not to burn through the rotten spot.

 

[Chopperhed]

I use a 15 gallon tank I salvaged off of an old service truck. I have an old single cylinder lung on it with a electric motor. I use my POS 99 dollar oilless unit as a storage tank. I quit using it after the regulator blew apart. I replaced the regulator so its useable if I need the extra cfm, but it's so **** noisy, I never turn it on.

My step dad used to use old propane tanks as portable air on the farm. I have no idea how safe they are, but they have to be safer than the 50 yr old beer keg that I got with my old single lung compressor. The guy I got it from swore he had it to 100 psi, but I wouldn't trust it.

I'd try the wrecking yards and look for an old air equipped service truck. They are pretty common around here. You can probably get the tank cheap. I got mine for free, and I knew it's life from install.

 

[BHD]

Stationary Air Tanks - Air Compressor Accessories - Grainger Industrial Supply

 

[BHD]

Stationary Air Tanks - Air Compressor Accessories - Grainger Industrial Supply

 

[BHD]

Stationary Air Tanks - Air Compressor Accessories - Grainger Industrial Supply

tanks are savable but expensive.

 

[BHD]

Stationary Air Tanks - Air Compressor Accessories - Grainger Industrial Supply

 

[BHD]

.posted three time and would not show up then I went to advanced and they all showed up,

sorry about the mulpital post,

 

[JRP]

When I was 14 I wanted a compressor and saved up $200. Sears had the 2hp one, probably like yours, on sale for $400. I asked dad if we could get it. No! " well, if I could save up half, could we get it? " "OK, if you save up half." "OK, here is my half".

I still have it, and it did get a hole in the belly. I found a large flat head screw, cleaned up the hole, screwed in the screw, and brazed the screw head to the tank. Still works OK. Great compressor.

Watch school auctions. Large AC systems use-compressed air to control dampers. Once a compressor breaks the just replace the whole thing, as there is plenty of tax money, and give the old one away at the auction. 3 phase units sell cheap. Cut the compressor mount off your tank and weld it to the larger school compressor tank, weld to the flat motor mount area.


Good luck.

 

[bigdeano]

Propane tanks are plenty strong for compressed air. I use a 20# tank as a portable air tank. According to Wikipedia propane pressure is 177 psi at 100F. The tanks would have to be rated at several times that. You'd have to make a provision to drain the condensation out.