By 803056 
Date 05-21-2010 03:52
Edited 05-21-2010 04:08
No insults were intended, just poking a little fun and kicking some dust.
Compressed air tanks are bombs if they are not welded by skilled welders. You have to understand that not everyone that participates in the Forum is a "skilled" welder. It was not too long ago that someone wanted to know how to plumb a fire extinguisher to use it as an argon cylinder. It was an accident just begging to happen.
Compressed air tanks are generally constructed in accordance with ASME Section VIII requirements and they carry an ASME nameplate indicating their safe working pressure, they have been engineered and pressure tested, etc.
I have attended a couple of funerals in my time because fellow welders that should have known better took short cuts. If I can pinch someone in the ass and make them think twice before doing something that can cause injury or even death, please forgive me, but I am going to give them a tweak.
Just make sure you know what you are getting yourself into before doing a "fun project" that could be your last. I would hate to write, "I remember Weaver, he was a hell of a welder, but not much of an engineer."
We welders tend to be self reliant, resourceful, jacks-of-all-trades type individuals. However, some of the things I have seen welders do are outright dangerous. I have one friend that does a lot of scuba diving. He took oxygen cylinders and used them as high-pressure air tanks for refilling his scuba tanks. That is not so crazy, but he welded over the letters and numbers at the top of the oxygen cylinders so no one could identify them as stolen. Many of the high pressure cylinders are chrome moly steel alloys that should not be welded without special procedures. Welding the tanks with E6010 or E7018 without preheat ain't the way to do it.
Others like to brag about welding fuel tanks full of gasoline; because everyone knows that as long as there are no fumes, it ain't gonna blow. "What about the fire you started in the garage because the gasoline was leaking on the floor dummy?" His nickname is "Zebra" because of the skin grafts.
The stories could go on and on and on, but I think you get my point. Be sure you know all the ramifications of what you are doing. Should the tank fail for any reason, is your life insurance paid up? Will it cover suicidal acts? Is it legal to use a pressurized vessel that doesn't meet code? Will you insurance cover the damages if it is known it wasn't a code vessel?
Best regards - Al
weaver,
Listen, we've all had a little fun poked at us. Al and myself are no exceptions. But you have to understand, while it may seem a fun project Al is absolutely correct, it can be dangerous. At the very least I would have an engineer (preferably experienced in pressure vessel calculations) run some calcs for you to make sure you have the proper thickness, configuration, and weld sizes to match what you are going to ask this thing to do. Head configurations will radically change the ability of the vessel to accomodate stresses. Flat heads are the worst. You also need to tie in what is probably not going to be RT/UT to the calcs.
Compressed air retains a great deal of energy which is why so many tend to stay away from it for industrial leak testing. Its dangerous.
I undertstand this can be expensive and probably not cost effective as far as building or buying is concerned. But be safe about it.
Better to have a little fun poked at you than having your family scraping you off your garage wall or pulling a hunk of steel out of your forehead.
My advice would be to buy one.
My 2 cents.
