Air Compressor Rehab. Old tank almost rusted out!

[David Hodgkins]

I'm in the middle of doing a rehab on my MKIII, after building my brothers MKIV over the past 1-1/2 years. While I was in the middle of my brother's build I moved into a little shop, about 400 sq feet total. Clearly the coolest thing about it is the 4 post lift. When I was spec'ing it out, I noted that the BendPak I ended up getting required reliable air. The only thing I had was a very loud single-phase 20 gal. upright compressor. My brother told me he had an old compressor I could use. It was bigger at 60 gal, and ran a lot quieter. I set it up in my shop and ran air lines to the lift and opposite wall. The system has 2 dryers and runs flawlessly.


The system was only pressurized when I needed it, and the compressor was always turned off at night, so it was seeing light duty. I never bothered to drain it, as the line driers were always dry. Then a few weeks ago I decided to go ahead and open the drain plug on the tank to see how much water was in the tank. I opened the drain and nothing came out. That would be OK except I had some air in the system, which meant the drain was plugged. I tried to stick a screwdriver into the opening and all I got back was a ton of rust. BAD sign. So I unscrewed the plug and this is what I found:


Yeah. not good at all. I looked at the tank and discovered it was made in 1987. That means it's almost 30 years old. I decided to retire it immediately as it seemed to me that a tank with that much rust in it is a safety hazard! Those of you that know my story would know how much I have an aversion to things that can explode so pressurizing that tank instantly became very uncomfortable.

So the first thing I did was take it apart. Pretty soon the tank looked like this:


...and my nice engine turning jig looked like this:


Well now my MKIII rehab project is at a standstill until I get a new tank installed. Not really knowing what I was doing, I located a local air compressor place and ordered a new 60 gal. horizontal Manchester tank with a deck on top to mount the motor and compressor to. I should have realized the decks come in different widths and heights! So the tank shows up at the shop and it's not until I start mocking up the compressor that I realize the deck is almost 2" too low and that the pulley sits lower than the base of the compressor and was now hitting the too-wide base. After taking a lot of measurements and head scratching I came up with a solution: mount the motor and compressor on some kind of 2" adapter plate. I went to the local industrial metal supply house and found another solution: 2" square-tube steel pipes. After some more measuring I went back and had 4 pieces cut, two at 8" and two at 10". It turned out that by using those tubes as mounting rails I wouldn't need to do any other modifications to mount things up. Well I did have to make one more item but I'll get to that in a bit.

Another problem I had was how to hook the system back into the line, since I had to cut it out. What I ended up using was a reverse thread pipe and coupler. I found these at a local pipe store along with the rest of the plugs I needed for the new tank. By sliding the tank over about 6 inches I was able to add the coupler and pipe piece right at the exit of the tank so if I need to disassemble it in the future I can separate the tank from the line by unscrewing this one piece of pipe.

In order to mount the compressor I had to mark and drill 4 holes but for the electrical motor I added 4 new mounting slots, so that the motor could be adjusted to put tension on the belts

So I broke out the grinder and went to work, after drilling out the outer edges of the slots:


After I cleaned up the cuts with a file I had the base ready to mount the motor and compressor:



One other thing I had to "fix" was the switch for the motor. Due to the low height of the deck I had to create a mounting plate for the switch. I found a piece of steel plate at Home Depot and fashioned it up without issue. Once that was created I was able to put the whole system together again. For the feet I had to buy some rubber disks that have a plate and bolts attached to both sides. The old tank feet were cupped and used a piece of rubber inside the foot-cup but the new feet are flat so I had to do some re-designing so I could still use the vibration isolating feet from the old setup:



I was able to pressurize the lines and I'm now back in business! I got set back a week but now I feel a LOT safer!

[Jeff Kleiner]

I'm more than just a little disappointed that you didn't polish the tank and engine turn the motor & pump deck

Glad you're back up and running!

Jeff

[David Hodgkins]

I'm more than just a little disappointed that you didn't polish the tank and engine turn the motor & pump deck

Glad you're back up and running!

Jeff

You know, your right. I could of at least polished and ET'd the new switch mount plate. Good idea!

Baaa-----ling!

[68GT500MAN]

Looks good David. Compressor tanks are subject to internal rust since the water is condensing in the tank. I just had two 500 gallon tanks replaced at work since they would not pass the tank inspection due to the wall thickness degrading. You did the right thing by replacing the tank.

Now about the BLING.........
Doug

[WIS89]

Dave-

May sound like a bizarre question, but I will ask anyway. I noticed you put isolators on the feet of the compressor, which I think is a good idea. However, I also noticed that your air line connections going out of the compressor are hard lines. You may experience some micro fractures on those lines, because of the movement that will be inherent with the on/off cycles of the compressor motor. It might (and I mean might) be worth putting in a flex line between compressor outlet and the rest of the hard lines; just to be safe.

Nice overhaul! And, how about that bling!!

Regards,

Steve

[frankeeski]

It might be worth putting in a flex line between compressor outlet and the rest of the hard lines; just to be safe.

X2. I run a 3/4" stainless braided line from mine to the hardline. My compressor is also outside of the normal work zone so it the flex line or compressor was to suffer catastrophic failure, I nor anyone else is in the danger zone.

[David Hodgkins]

Dave-

May sound like a bizarre question, but I will ask anyway. I noticed you put isolators on the feet of the compressor, which I think is a good idea. However, I also noticed that your air line connections going out of the compressor are hard lines. You may experience some micro fractures on those lines, because of the movement that will be inherent with the on/off cycles of the compressor motor. It might (and I mean might) be worth putting in a flex line between compressor outlet and the rest of the hard lines; just to be safe.

Nice overhaul! And, how about that bling!!

Regards,

Steve

X2. I run a 3/4" stainless braided line from mine to the hardline. My compressor is also outside of the normal work zone so it the flex line or compressor was to suffer catastrophic failure, I nor anyone else is in the danger zone.

Noted and I appreciate the insight. I'm replacing the 90 degree turn hardline today.

I'm trying to find a manual online for the compressor but all the links I'm finding are scary looking. (EDIT: as a matter of fact I got stung and spent 1hr+ flushing it out of my browsers. Yeah.)

I STILL need to find a manual so I know how to maintain the pump. It's a nice one and I'd like to keep it!