Welding Tips and Tricks

When copper is used for supplying oxygen in the shop What is the proper fit up Procedure for said pipe? This copper pipe will supply oxygen for Propane torch and rosebud work.

Welcome, carnocker,

I do oxygen-clean work all the time. Fit-up is a small issue. "Clean" is a big issue. Rediual oils in the piping, fittings, and valves can ruin your day.

As for fit-up, it can be TIG welded, as butt-welds, socket/lap welds using standard copper fittings, or silver-brazed with those same fittings. Typical plumbing solders are not recommended due to the action of a pure oxygen environment on them.

"Clean" is the tricky issue. Residual oils from the extrusion of the piping can spontaneously combust at room temperature in a pure O2 invironment. All pipes and fittings should be thoroughly flushed first with laquer thinner, then washed in detergent. "BlueGold" is the industrial standard, but for your purpose, a strong solution of uncented Dawn will do. Then a thorough rinse with water.

All valves and gauges should be rated for oxygen service, and preferably "oxygen clean" in a sealed bag to be opened just before install.

How do you know it's clean enough? Long-wave UV. A discount solution is available at the auto parts store in the A/C section, with the flourescent leak detection stuff. It's not up to industry standard, but should serve your purpose. Shine it down the pipes, and look from the other end. Anything that glows is not clean yet. Check the fittings the same way, in a dark room.

I know it sounds like overkill, but if something in a copper pipe spontaneously combusts in 100% O2, the pipe will burn, too, and you'll have a class "E" fire on your hands.

Ask any questions you like.

Steve S