MIG brazing?

Well, I'd say that you can't braze with MIG because it is a different process. Brazing you heat the parent metal and let the lower melting point brazing rod be melted from the heat and sucked into the join. MIG doesn't heat up enough of the parent metal without melting it too.

However if you are asking why they don't sell bronze MIG wire? They do:

"Todd Rich" wrote: if you are asking why they don't sell bronze MIG wire? They do:

Silvere soldering is also called "silver brazing." So, I believe it would be appropriate to include MIGing in the brazing category. However, for the reasons you listed in the main paragraph, I don't see why it works.

But couldn't you just turn down the amps so that you didn't melt the base metal? You can TIG braze.

Not yet satisfied, Bob

I was under the impression that you can and they do.

Jim [Disclaimer--- I am still in the 'read about it until you know what you're going to buy' stage, so I might be interpreting 'brazing' differntly than you.]

My dad was a machinist all his life. I met one of his buddies he shared rides to work with. His buddy MIGged with copper wire to weld copper bars together. My dad would then turn the bars on a lathe. They worked at Stauffer Chemical Company and they produced a lot of chlorine and other nasty stuff.

Steve

Tried MIG-braze round at Kemppi - using SIF consumables

Feels like welding but deposit bronze.

Advantages - is needed these days - is currently indispensable and used in making new cars

- low / no distortion, as don't melt the sheet metal

- join very high strength HSLA (High-Strength Low-Alloy) sheet metals. Can't melt them as weld without turning them back to low-carbon low-strength sheet - whereas MIG-braze preserves HSLA strength (1000MPa - 4 x traditional sheet strength easily provided)

- preserves galvanising on back surface - thermal cycle is low enough temperature and short enough that zinc galv does not boil off back surface (with high strength, sheet is thin - would perforate with corrosion in no time if galv lost).

The MIG wire quickly became known as CuSi3 (SIF said they soon had people ringing up asking for "Kew-si-3" regardless of their brand-named for it). Is Copper-3%Silicon-1%Mn. The silicon would be a pretty strongly biting "internal flux" as well as a desirable alloying element for strength. Manganese is probably for strength alone.

Idea is to keep power well-controlled so no part of the weld much exceeds 1000deg Celsius. Check this recollection if it's important to you - if recall rightly, the abs. max temp where the arc is on the surface is about 1050degC - but even for sheet metal, back surface was at less then 900degC (metallurgical evidence backed-up claims).

You can and I have. It works quite well.

It is excellent for joining stainless steel pieces. It doesn't scorch the the backside of the stainless steel because it never gets it hot enough.

It also works well on galvanized steel for the same reason. The weld never gets hot enough to burn off too much of the zinc.

I assembled 280 feet of stainless steel railing by MIG brazing with my spoolgun.

You need Silicon Bronze wire, (currently just below pure gold in price), and an argon or argon/helium shielding gas.

Well, it looks like you can. Though from what I've been seeing in the responses, it is mostly sheet metal, which makes sense. My mental concept for brazing usually pictures very deep joins, like putting a 5" ball on a cupped bar for a stake. Just had a hard time seeing MIG do that. Sorry for my lack of imagination. Todd

Thanks - I guess I could have Googled it, but then this NEW topic wouldn't have come up and the answers wouldn't be in the SEJW knowledge base :-).

Bob

Ernie Leimkuhler wrote: [ the definitive answer, the last word, if you will]

Ah, I did find a 2 lb spool for $32 (+ S&H). Might be worth it for those special occasions.

Thanks, Bob

Great sig on [I think] an old Mindspring forum- I must have it misremembered as I can't find it, but it goes something like; 'One asks, many learn.' [and I think it was attributed to Plato, at the forum-- but I can't find that either.]

Jim

This, however, would be copper welding.