Building Air Compressor

I am really uncertain about putting heat to a propane tank eventho it has been "aired out". I have heard guys use them; but, I have also heard that the metal will actual absorb some of the propane and create a potential explosion hazard.

Any thoughts/suggestions.

carl

Why is it that even a full light gage propane torch cylinder can be stored indefinetly without losing its contents. We are not talking about helium here. That gas can find its way around steel molecules.

The residual odor in a propane tank that has been purged is the smell of ethyl mercaptan. Unadulturated propane has no odor. The same is true of natural gas.

If you are worried, just ventilate the tank while welding. You will be way below the LEL (lower explosive limit) of any gaseous content, if any.

BTW, there is also something called the HEL (higher explosive limit). If the contained combustibles are too rich, they cannot ignite.

You should also know that propane is called a sweet gas. This means it is a non-corrosive gas and the inside of the tank should look factory fresh.

Propane tanks are rated for 250 psi. Rupture psi is probably in excess of 1000 psi.

As to the exploding tire, do you have a link to the accident report or, better yet, the documents from an investigating authority?

Propane boils at -44 degrees Farenheit and about -42 degrees Celsius. It turns to vapor everywhere but arctic regions and is easily swept out of a confined space with air. Nitrogen is overkill particularly when, as I mentioned before, the LEL, with 20 percent oxygen in the air, will never be achieved with several air exchanges per minute. You are more likely to have an explosive incident if you pass gas while smoking.

To compare a rotating tire doing 500-750 rpm while evenly absorbing, creating, and shedding heat to a stationary wheel/tire assembly heated at one point is rediculous. Forces such as centrifical, inflation, heat stress, and loading put high demands on tires, especially large diameter truck tires.

Your 10,000 degrees means nothing. Lightning is equivalent and people don't vaporize when struck. I suggest that the next time you heat a piece of metal by welding or torching, try dropping it into 20 lbs of water or about half a bucket. Place your hand in the water and I doubt if you will sense more than a couple of degrees of heat rise. The BTUs aren't there. This is why I would want to read the accident investigation written by a competent person.

Personally, I don't weld wheels, mounted or unmounted. If it is damaged, it needs to be replaced. They are a critical safety component with dynamic stresses that I can only guess at.

I have all my toes and fingers. You have to look hard to find any scars. I am safety conscious but not obsessive like you are. I have written dozens of required safety plans as a work pre-requisite on contracts with the Army Corps of Engineers. They are often 30 pages long. Most of my work was in "confined space".

Who said anything about materials other than propane?

Did I mention that I routinely cut domestic oil tanks with a torch and the only precaution I take is to do it outside? And yes, there is beaucoup oxygen inside those tanks.

I was once called out to sandblast a stress crack on a fuel tank on a large ledge truck. While I was packing up, the welder had already started welding it even though it was weeping diesel. And you want to steam a propane tank where all the gas has vaporised and been purged with a continuous air feed?

There is a large wheel repair outfit in my town. Only one of three or four in the entire country. They must have 10,000 wheels in inventory but they are all aluminum. They don't weld anything. They straighten and true them.

So you would compare a heavy weldment to a wheel? Why can't you stay on the subject? Please make your comparisons relevant.

I have recently torched about a dozen 275 gal domestic heating oil tanks. I cut them the long way and store cord wood and coal in them. I now have more than twenty palletized containers for my solid fuel and scrap.

When the tank halves are separated, there are always small puddles of fuel and saturated rust sludge in them. In some cases, there might even be a small flame no bigger than a burning sheet of paper. It is not a hazard or a problem but I do it outside.