mig welders?

Farwell · Aug 15, 2005

When I started brazing as a kid I would melt the brass and build a puddle instead of getting the base metal hot enough for the brass to flow on it. I agree if the brazing is done correctly it is very strong. In emergencies I have even used copper electrical wire as rod and it has held up for thirty years or more.
Farwell

Wannafish · Aug 15, 2005

Brazing, when done properly, will only provide a joint as strong as the filler metal. Arc/Mig (again, when done properly) will provide a joint as strong as the base metal.

Mike_C · Aug 15, 2005

I used to try brazing the exhaust pipes onto the header flanges on my Camaro, and the constant flexing of the pipes each time I rev'd up the engine would cause the brass to crack. It just could not take the torquing I was giving it. I'm pretty sure I had the metal hot enough.

uhmgawa · Aug 16, 2005

( If folks will see the welds,I'd go with the MIG.
Floor boards don't need to be pretty,and I'd save the money.
"MIG for pretty,stick for strong." )

I'd hazard where you are drawing this view would
be from commonly available equipment. Inexpensive
240V input stick welders are available which can muster
200+ amps AC output even if at comical duty cycles.

Inexpensive MIG machines are usually 120V input
which limits output current in the 100A DC ballpark.
240V MIG machines certainly exist however they are
less common.

MadReferee · Aug 16, 2005

( 240V MIG machines certainly exist however they are
less common. )

Actually, most MIG units 150-175 amps and all units over 175 amps are 230/240v machines and they are the most popular with those who do serious hobby and professional fabrication. Also to weld more than 1/4" the 230/240v machines are the most efficient.

have_blue · Aug 16, 2005

( And I agree with Madreferee, you can make some darned strong welds with MIG. )

By pre-heat the thick stuff with a torch, and you can penetrate real good. Even a little pre-heating can help, if you are welding on something that is heat sensitive.

GeneD14 · Aug 16, 2005

( ( And I agree with Madreferee, you can make some darned strong welds with MIG. ) )

I was a manager at a large heavy metal fabrication plant and all of the welding on armour plate from 1/2" to 2" was done with MIG because of the speed, weld quality, penetraition. These MIG machines were big Lincoln 3 phase industrial models. In heavy fabrication of equipment MIG is the industry standard. It's not just for looks.

uhmgawa · Aug 16, 2005

( Actually, most MIG units 150-175 amps and all units over 175 amps are 230/240v machines and they are the most popular with those who do serious hobby and professional fabrication. Also to weld more than 1/4" the 230/240v machines are the most efficient.)

Agreed. My point was the proliferation of low-cost 120V
MIG welders seems to have created this misconception of
MIG being a light duty operation.

Or stated a bit differently, if you need to weld thick
sections the cheapest machine to acquire is going to
be a 240V AC buzz box.

uhmgawa · Aug 16, 2005

( In heavy fabrication of equipment MIG is the industry standard. It's not just for looks. )

At the other end of the spectrum is the ability to
dial down the feed/current of a MIG machine in
order to make fairly intricate operations.

I had a sliding mechanism with worn flanges
which needed to be restored to the size of about
1mm^3. I was able to build up a the area via a
MIG-applied bead and afterwards grind it to shape.
As the base metal was about #24 attempting this with
a stick would have likely obliterated the base in the
process.

Soundguy · Aug 16, 2005

( I HAVE LEARNED TO WELD SOME PRETTY THIN STUFF WITH MY OLD TOMB STONE over the years,but lets face it it aint easy.
)

I weld thin metal al the time with either the 30a or 70a setting on mi stick welder.. and either 1/16 or 5/64 sticks.

Soundguy