Are check valves required at each regulator. I assume the regulator itself acts as a check valve. Any other tips will be welcome as well. I have just ordered a bottle, but nothing else at the moment.

I do this all the time, but like others state, the edges must be cleaned. I use a 60 grit slap disc and it's fast. I have successfully used a 40 amp machine, but 4mm alu is at its limit. It is better to use a 60 amp machine. I only use air. perhaps nitrogen would work better, but I would still sand ...

I am looking for a recommendation for welding a con rod journal on a forged AISI 4140 crankshaft. This crank is a single throw unit with two main journals with two splined ends. I know that before welding, the crank must be annealed, as it has been induction hardened. I also know it must be preheate...

Soap stone marks are temporary and wipe off easily, as others have stated. Its advantage is that is does not disappear when hot. Its most common usage is doing layout lines for cutting with oxygen/acetylene. It is invaluable and very inexpensive.