Sorry i know this is a little off topic....

So my boss gave me his old air compressor (just like http://cgi.ebay.com/ws/eBayISA...&rd=1 ) because it has a small crack in one of the tanks. It is under the fromt foot. It looks like it might have fell on on foot and pused it back to put a small crack in the tank.

I was thinking about pulling the motor off so i can work on it. Plasma cut the leg off, grind it all smooth and tig the crack back togher.

The other option is to pull the motor off flip it over and braze the entire area around the foot. I am a little concerned about the brazing under preasure(100-150psi)

Now both the tig and the brazing will be done by a friend that welds bicycle frames, so he is very use to welding very thin metal. And yes i know the tank has to be open to allow the hot air and gases to escape.

 

Welding on that is actually illegal. It is an ASME coded vessel, and without the proper certification, it is illegal to weld on it.

That said, I'd grind a bevel in it and weld it up with TIG. Make sure and open up the tank by pulling a valve off, opening a hose, or something, while welding.

It's likely at least 1/8" thick.

 

Well i could have a LA cert structial welder do it. If they can wels a building togher i am sure they can weld a tank back togher.

Yes the tank will be open. I know better than that

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Racermech &raquo;</TD></TR><TR><TD CLASS="quote">Well i could have a LA cert structial welder do it. If they can wels a building togher i am sure they can weld a tank back togher.

Yes the tank will be open. I know better than that </TD></TR></TABLE>

Actually, you have it backwards. Most buildings are welded with SMAW (stick welding) and done in accorance to ASW D1.1 Structural steel codes....which are MUCH more lenient than ASME Section IV, which is Boiler and Pressure Vessel Code. For example, D1.1 will allow more undercut, more porosoty, doesn't require cleaning the metal free of ALL dirt, oil, mill scale and debris.

Maybe this guy can do it, and maybe he can't... but Unless you're pretty confident in your abilities, I'd reccomend finding somebody with pressure vessel experience. It's a lot easier to weld up a building than to weld up pressure vessels.

 

did you happen to see the pics of the guys air compressor tank that exploded in his garage and it was like a bomb went off. Huge holes in the wall and out the outside. IT also went through the side of the car. It is posted in gdd. I would not mess with a tank that has a crack in it. When something is under a **** load of pressure you really don't want that to explode.

 

dont **** around with a cracked tank, get a new one, it is not worth the chance of it ripping open and destroying whatever area it is in.
Most building struts are under a lot less pressure than your tank is when fully charged.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Engloid &raquo;</TD></TR><TR><TD CLASS="quote">Actually, you have it backwards. Most buildings are welded with SMAW (stick welding) and done in accorance to ASW D1.1 Structural steel codes....which are MUCH more lenient than ASME Section IV, which is Boiler and Pressure Vessel Code. For example, D1.1 will allow more undercut, more porosoty, doesn't require cleaning the metal free of ALL dirt, oil, mill scale and debris.

Maybe this guy can do it, and maybe he can't... but Unless you're pretty confident in your abilities, I'd reccomend finding somebody with pressure vessel experience. It's a lot easier to weld up a building than to weld up pressure vessels.</TD></TR></TABLE>
OWNED

 

Thanks did not realize the ASME was that strict. I still might know one guy that has some vessel experience. I guess i will have to go on the hunt and see if I can find him.

So i guess i am going to look into running just a single tank, see if that will work.

To the guy that said OWNED.....go away.

 

It pry isnt the best idea. But it will probally be alright if you have a experienced welder. The welders at my work weld vessels that are going to see over 300 psi of pressure.

 

And there inlies the rub, the welds at your work weld vesseles, my welders weld buildings....

Anyways i did some searching and i figured out that a new tank would only be about $175, so i am going to order one up, build a nice 4 wheel rolling rack and weld the feet (not the tanks) to the rack, no worries about exploding tanks that way.

Still only $175 for a $600+ compressor.

 

Be careful with your tanks

https://honda-tech.com/zerothread?id=1065634

 

it acually takes a higher cert to weld on a vessel

 

If you weld it, go get it hydrostaic tested. But I wouldn't weld it

 

hmm i have a small 10gal at home, its an oldie. It has rust on the bottom and a small pinhole leak. Maybe i should replace the tank lol

I just never figured 100psi would do that to a steel tank....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted-delslow &raquo;</TD></TR><TR><TD CLASS="quote">It pry isnt the best idea. But it will probally be alright if you have a experienced welder. The welders at my work weld vessels that are going to see over 300 psi of pressure.</TD></TR></TABLE>
Something you may find interesting.. I have welded 3/8" tube with .035" wall thickness...and it held over 1000psi. I have welded 1/4" tubing that held over 1800psi.

What people forget is that psi means Pounds PER square inch. Therefore, 120psi in a small tube will not be as much force as 120psi in a large compressor tank.

As for Hydrostatic testing... this is testing by using water, rather than air. It is much safer. That tank that blew up would likely never have moved from it's location if it had burst from water pressure. The reason is because water will not compress and air will. So when the tank gives, air has much more force as it expands back to atmospheric pressure. Water would not have to expand. It's the difference in putting your weight on a car spring vs a rock. The rock will not expand or compress, and the spring will.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by foursquarepunk04 &raquo;</TD></TR><TR><TD CLASS="quote">it acually takes a higher cert to weld on a vessel</TD></TR></TABLE>
Yes, that is ASME Sect IV.

 

Sorry kind of topic, so would it be a bad idea about buying a used older compressor that has just been sitting in someones garage ?

 

no i would fill it full of air and sprat soapy water on it

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Racermech &raquo;</TD></TR><TR><TD CLASS="quote">I did some searching and i figured out that a new tank would only be about $175, so i am going to order one up, build a nice 4 wheel rolling rack and weld the feet (not the tanks) to the rack, no worries about exploding tanks that way.

Still only $175 for a $600+ compressor.</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by foursquarepunk04 &raquo;</TD></TR><TR><TD CLASS="quote">no i would fill it full of air and sprat soapy water on it </TD></TR></TABLE> And what the hell would that do. If i was to wled it then fill it with air who knows if it will explode or not. I could see it now. O look the soap is starting to bubb.........BOOOM......dead....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Racermech &raquo;</TD></TR><TR><TD CLASS="quote">
And what the hell would that do. If i was to wled it then fill it with air who knows if it will explode or not. I could see it now. O look the soap is starting to bubb.........BOOOM......dead.... </TD></TR></TABLE>

lol, thinking the same thing. Maybe it will make a cool hissing noise before it explodes in my face. So is there really a way to tell if a used compressor is any good ?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 90blackcrx &raquo;</TD></TR><TR><TD CLASS="quote"> So is there really a way to tell if a used compressor is any good ?</TD></TR></TABLE>

Ultrasonic testing, or xray. Granted, if you can take a hammer and tap around on the bottom and it cracks, you probably better not buy it. In other words, if the rust is severe inside, the material will be thinner.

 

dude just jb weld that thing and call it a day
haha joking by the way

 

Sorry to get off track but, if I am buying a used older air compressor. When will I know when to shut it off, if the owner never new how big the compressor was ?

 

My uncle has a compressor with a tank that leaks because of cracks, its been welded few times, so far we're still alive