Arc experiments

Sounds like you might need an oxy/acetylene outfit. ;-)

If you like the COLOR of braz>

please feel free to try the following and keep everyone posted

If you struck an arc with a brass rod it would vaporize in the arc. Since there would be no shield to keep the oxygen away it would be a rather smoky experience giving off zinc oxide fumes. If you strike up a tungsten without shielding gas it turns into a sparkler. Covering a bad weld is not uncommon. If you use a cellulose based electrode you can often burn through the slag inclusions and dirt. The reason is that this type of electrode produces a relatively large cloud of carbon dioxide gas to shield the arc as you attempt to burn out the messy weld and fuse the thing together. This method is not considered good practice and if anyone accuses me of doing such a thing I will Deny Deny Deny! Often welders will have a lower continuous rating at which they can be operated across a dead short such as the electrolytic tank you describe. This is dangerous stuff unless you are thoroughly familiar with the operation of your equipment. Randy

Yeah, I expected zinc fumes, so would be doing this in breathing gear. I wonder if *all* of the zinc would thus burn off? Perhaps I could refine the copper back out of the brass ;-)

Oooh, sounds pretty! But not as pretty as my new "magnesium electrode" idea, heheh.

I'd just do it all outside at good few arm's length with a decent isolator switch... there are two kinds of people who experiment with finding the limitations of their equipment: Ones who do everything at a good few arm's length with a decent cutoff device, and those with missing parts :-)

ABS

You can't do this with brass, but you might manage it with bronze.

The problem is that zinc _boils_ at a pretty low temperature and will effectively vanish.

There is "MIG brazing", where the wire in the MIG machine is a bronze, typically "CuSi3" - copper with 3%silicon plus probably smaller other additions. Relies on shielding gas to keep arc and metla out of atmos. Works very well.

Other respondents have described how your scheme would be, at best, messy.

Richard Smith

"Richard Smith" wrote: There is "MIG brazing" (clip) Relies on shielding gas (clip) ^^^^^^^^^^^^ What shielding gas, please? I'm set up with CO2, and I'd rather not buy another bottle just to play around. Also, since there is no flux, I imagine that grinding to a sparkling clean surface is necessary.

Shielding gas is Argon. That would be "commercially pure Argon" - the stuff you use with a TIG welder.

Wipe with a solvent for clean stainless and very-low-alloy steel - visually clean is OK (?)

Tried this process at UK branch of Kemppi (Finnish welding m/c manufr'r). Is good.

CuSi3 is something like Cu-3%si-1%Mn

See SIF in UK

Richard Smith

I've got an old Soda Stream cylinder of CO2... perhaps I can figure out how to open it (scarey: it says it's at stupidly high pressure) and empty some into a sealed tub and let gravity keep it in there for a few tens of seconds.

I'll post about my experiences when I get time to try them :-) Rainy weather outside has been depriving me of opportunities lately... I had a dry period long enough to make a new pair of crucible tongs, however:

One of my welding books tells me you can learn to strike an arc by just tapping the surface exactly where you want to start. My attempts to do this are always either too slow (electrode sticks) or too fast (arc starts, but the bounce from the tap takes the electrode too far away and it goes out again).

I will continue to practice...

ABS