Welding Tips and Tricks

Just picked up some gas lenses and am wondering how much of a reduction in flow I should try. Right now I'm welding some aluminum at 15CFH. Is there a standard % of reduction?
Thanks, Peter.

It all depends on how still the air is where you weld.

I've welded aluminum at as low as 5 CHF in dead-calm air, but 10 CFH is probably the practical minimum.

Factors include air movement, tungsten stick-out, and your preferred cup angle.

Otto. Thanks for attempting to answer my question. I think you misunderstood what I was asking. If one is welding at 15CFH given all conditions, what is the % reduction in gas flow if switching to a gas lense under the exact same conditions?

On average, 25-35%

On a large cup, say a #12, the reduction is closer to 35%, where on a #4, you're probably closer to 25%

In your example, with a #10 or #12 cup, you could reasonably expect to drop from 15 CFH to 10, all other factors being the same.

All this depends on many factors, of course. If you use a lot of stick-out for a particular weld, the gas lens is a bigger saver over what a standard collet-body would require.

If you weld outside, as on an industrial job, you'll likely need a lot of gas regardless, and the savings will be less (but the smooth flow benefit is great).

Steve S

Great topic - I don't mean to hijack the thread, but was wondering if I could ask a related question?

What would be a reasonable flow for a #7 gas lens on aluminum in still air?

I've been using 15cfh and having some welds that don't look as shiny as I'd like at times - could the flow be so great that air is being drafted in, or am I wasting gas ?

Thanks!

15 CFH is fine... Don't be afraid to try higher, though I doubt that's the problem.

Sometimes, especially on heavier sections, the weld holds heat so long that it "frosts" as you advance and move the gas coverage forward, particularly if you hold a cup angle of more than 15 or 20 degrees, so the back (finished) part of the weld doesn't see gas for very long. It's not uncommon for those who hold a sharper angle to run up to 35 CFH to get coverage behind the cup.

Just guessing, though.

Steve S

Might consider fashioning a trailer.

Example:
http://www.pwt-online.com/products/prodGSD.htm

Alexa

Makes sense, thanks!

-- Pete

Thanks Otto, that's what I was looking for.
Peter.