Lasering base metals

Don’t hafta do it much but I’m having difficulty getting a good weld,
particularly on brass. It either spits apart or does nothing, can’t
seem to find the right settings, can’t get that lillypad puddle. I
don’t have argon yet, could that be the problem? A few times I have
filled with silver solder laser wire and that seems to help but the
color match is nonexistent. Gold laser wire hasn’t been so helpful.
Does anyone have experience with base metals in this regard?

Hi Neil:

I did some brass hinge knuckles for a mockup once. Don’t remember
the settings particularly, but I was definitely using argon. Down
around 1PSI output A2, medium power, wide-ish beam, and probably a
square ramp profile. They held just fine, but I was just tacking them
before soldering, so my standards for ‘fine’ were pretty coarse.

FWIW
Brian.

I’m with you, I have not found the right combo for brass. Repaired an
element of a large brass casting this week and it was a struggle all
the way. Finally got a good weld using an alloy for eyeglass repair:
silver, pal., ? alloy. No color match of course, but I was able to
blend it pretty well.

I’ll get to re visit the problem next week as the store that sent me
the job gave incorrect orientation on a vital part, so I’ll be
cutting threw that weld to re align the assembly, and I’ll get a
chance to really study my weld. And try again. Argon didn’t seem to
make a noticeable difference.

The high amount of zinc in the brass makes it virtually impossible to
get a good fusion weld. The zinc has such a low vaporization
temperature that it will turn to gas when you hit it with the super
hot laser or electrical arc as that vapor blows out of the puddle you
end up with massive porosity. This is why the silver solder or silver
pd alloy makes a some what ok weld in that it dilutes the amount of
zinc in the weld puddle. So the less zinc the better the weld.

Jim

James Binnion
James Binnion Metal Arts

Hi Neil the Jeweler,

I don’t have experience with base metals, but using a black magic
marker at the spot you want to weld can be helpful.

Good luck.
Michelle