Welding; How much undercut?

"J.Kahn" wrote in message
. ..
Fortuant1 wrote:


Welds are pretty good, but I am having one further problem; After a
minute or tow, my torch (a meco) often tends to go oxy, even though I had
it set right in the first place. Not a big problem once I spot it early,
but annoying al the same. It seems to stabilise after a while. Could be
that my acetylene tank is just running down, but I thought that the
regulators would cover that almost until the gas ran out.. Maybe I need
new regulators..

I had the Kent White set and the Medalist acet regulator would hunt and
surge and finally sent it back. Went out and bought another one locally
which seems to work well. His video is highly recommended.

I find the acet needs a few seconds to stablize any time there is an
adjustment on that side.

I have a Meco too and it is great, but seems to pop about as much as any
other torch. Welding 049 with a N-2 tip I had the gas turned way up and
it would still pop. May just be dirty.

Kent also includes and recommends E70 rod but it is terrible rod to gas
weld with and I switched to coat hanger to practice. Went out and got
some RG45 which is wonderful.

I can make more or less airworthy welds now, now working on making them
look nice. Things got a LOT easier once I learned the importance of
using the rod to help control the heat applied to the puddle so now I
almost never get burnaways. Still having to do a lot of stopping and
"adjusting", but about half the time now I can find that sweet spot where
the puddle is just right, the torch angle and heat is just right, and I
just have to move it along feeding the rod and the resulting bead looks
like a tig bead.

John

Hi John,

If you have a lot of problems with a torch popping, try running a little
less OX. From a perfect appearing burn, you should richen the mix just
enough to produce a little bit of feather. Maybe a 1/4 to 1/2" will usually
make a world of difference.