Welding Tips and Tricks

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.

Most regulators do not act as a check valve. You can do it with out check valves and get it to work but a dedicated mixing valve designed for the gasses you will be mixing will give you the best results with the least miss match on the mix ratio.

Actually. I've done it without check valves... A regulator in good condition will not allow enough back-flow to have noticeable mixing through the life/use of the contents. Check valves are cheap insurance, though.

You do not need a "wye" fitting to mix the gasses, a tee will do just fine. The gasses mix very quickly from a tee due to the induced turbulence, and there's a lot of hose between this tee and your weld.

Your flowmeter/regulators should be matched in pressure, i.e. each set at 60 psi, so your mix is consistent at the start. (A second of pre-flow will completely stabilize it.)

Keep in mind, unless you have a helium-specific flowmeter, it's hard to read Helium under 10 CFH, so it's challenging to set a precise ratio.

Steve S

I just buy 75/25 He/Ar pre-mix. S/F....Ken M