You're getting good info that those little tanks are expensive, low capacity, and will eat you alive costwise. Plus, the regulators fit no other size tank, so if you wanted to move to a larger size, they would have to be changed out. Not good, in any respect, IMHO. Better, IMO, to try for a used oxy-acet welding rig of good quality and known brand that maybe costs $75-250 (I realize this is a very wide range, but it's completely depending upon whether you are getting the tanks with the outfit...and a cart to roll them around on....and a wad of welding rods that are of course unrelated to silver but they increase the overall utility) and then change the fuel tips to propane tips and use propane instead of acetylene) In this way....you are buying something that will retain resalability if you decide to exit the endeavor. Stick with known quality brands and FIND OUT whether you can get propane tips (you can) and WHERE before you buy a rig.
I would urge you to ponder the end-to-end economics of "processing" your sterling silver. I do not believe it possible to improve your position by more than a few cents per ounce until you are processing hundreds of pounds. Eg; if you are chemically refining sterling to .999, the glassware and the safety issues and the chem costs are inputs, as is your time. As they say, "do the math".
First question: In what form is your sterling, right now, in your hand, today? Scrap junk jewelry, forks...?
Second question: What would you like to end up with? (money or .999 or the experience of doing whatever it is you are contemplating doing, with no regard to the monetary cost)
You can right now today trade your sterling to GRF member scrapman1077 for excellent quality rounds pretty favorably...it will cost you a buck an ounce, but the "buck an ounce" thing is almost impossible to avoid. It just is. Whether you buy with cash or trade or however you go, there is an implied "coining cost" of a buck an ounce in the creation of recognizable rounds (aka "coins) that become a lot more tradable than a blob of metal. I have never found a way around this. But this particular "buck an ounce" means you get the coining charge AND don't have to use chemicals to refine. Just send him your raw weight and he will accurately and quickly and reliably translate to rounds, at his posted rate. Done, finished, end.
Another thing I will point out: The cost per ounce to process increases quite a bit as the price of silver falls. Nitric acid in small amounts is not cheap. And, to be sure, the "buck an ounce" coining charge is a lot bigger percentage of the final "coin" price with silver at $20 versus $30. There are a small number of things in the refining game that you have zero control over and are inescapable; and I don't say that to discourage; only to inform.
