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To: VintagVW_at_listproc.sjsu_dot_edu
From: mwest_at_cdsnet_dot_net (Mike West)
Subject: Welding Stuff, mig, wire welder, brazing ..
Cc: type2_at_type2_dot_com, Vintage Bus <vintagebus_at_type2_dot_com>

This is just some welding stuff I heard of or have used . .

Reading of a body man who uses Brazing Wire in his Mig . . .
Reverse polarity and straight Argon gas . . .

"Greatest thing since sliced bread", he says . .  this I want to try.
It sounds like a weeener . . . :-)  even less heat in the metal

While speaking of filler rods or wires . . I use an extra filler rod
with the wire welder, where I have a big gap or hole . .
You have the welder in your right hand and you feed a filler rod in
like you're gas welding with your left hand . . 

This filler may be a gas welding rod . . or coat hanger, or even a 
flat strip that fills the gap . . 
Copper backing strip will keep it all from falling out on you . .

Even when stick welding . . I've beat the flux off another welding
rod and lay it in the bottom of the gap and weld over it . . .

Straight/Reverse Polarity . . . some welders have a switch . .

If it's a stick welder you can just reverse the plugs of the cables . 

Electricity . .  the little electrons . . flow from negative to 
positive . . . 

In welding, that means with straight polarity, negative work, positive
electrode, the heat is hanging in the electrode . . . 

Reverse polarity puts the heat in the work instead of the electrode.

With sheet-metal, straight is what you want . . if you're doing some
heavy material and want good penetration, use reverse polarity . .

Some stick electrodes don't work except with a certain polarity . .

It was mentioned in an earlier post that you can get a magnetic flux
going in a weld area and the weld just seems to blow out . .

This is not new .  . . . if you run into such a phenomenon, tho I 
don't know how you will recognize it if you're not already experienced, I
used to have to wind the ground cable first one way 
around the work piece and then the other till I got the flux to cancel
out . . sometimes you can just wind your ground cable across the 
welding cable . . no science . . straight magic . . :-)move the part,
say a chant or two . .

Penetration, per se, is in the voltage . . . to control the voltage,
pull the electrode farther back from the work . . . that's the electrode
your wire is running out of if you gat a wire welder/mig . .

Some have asked about the diff between a wire welder and mig . .
None is my first answer . . . but now they have flux core wire welders
that don't use gas so we would call that a "wire welder" I guess ..

"MIG" stood for "metallic inert gas"  was a milspec and AWS designation . .
new designation "GMAW" gas metallic arc weld . . 
further refined this week to "GMAWG" I think, for a  ". . . gas"
on the end.   Don't quote me . . . :-)

Getting back to the voltage . . when your weld is getting too hot, 
you pull back a fraction on the electrode . . . the wire will still
get to the work, trust me . . :-) you are literally lowering the voltage. 

Up-hill welding will give better penetration but also more heat,
down-hill the reverse is true . . 

Second trick: keep the heat in the heavier or bigger piece of metal,
it can handle it. . . you do this by directing it at the edge of the big
piece and just flirting with the thin piece . . 

How do you know if it's too hot . ? remember the color it was just
before it fell out on the floor ?   that's too hot . . :-)

Yes the reverse is also true . . if you need more heat in there, get
that tip in a little closer . . 

The Big Clue : what does a good welder sound like ? a good wire welder
sounds like a bee . . a 60 cycle bee  . . even a stick welder has a 
sound like that  . .  you'll know when it's right . .

That gets us to those corner fillets . . 3 corners at right angles
come together . . . farside . . . :-) naw, give you a break this time.

Looking at your wire welding tip, you have the gas shield over the 
center tip that the wire comes out of . . .

The wire runs out and shorts on the work piece and melts and the gas 
shields the whole thing from air  . . otherwise it just turns into a 
mess . . bubbles 'n stuff . .

For the Neophyte . . if this were a shielded arc rig . . the one that
doesn't use gas, it has a flux, like the stick electrodes, but it's
inside the wire . . when the wire melts, so does the flux and it covers the
mew molten metal and shields it from the air . . 

Ok back to the nozzle  . . the gas shield thingy . . the tube there . 

On flat work, the tip elctrode and the nozzle are both about flush,
you're running between "need to see" and have to protect the tip from
touching anything . . center is the "hot" part . .

With it flush and tipped up about 45 degrees, your tip is about 1/2"
from the work . . . this give you good control of said tip . .
Push the gun as opposed to pulling like a stick arc . .

For working in a fillet situation . . a right angle  __[ , you pull the
nozzle back and expose more of the tip so you can hold that 1/2"
from the work . .

This is all because of that big nozzle diameter . . 5/8-3/4" . .

There are alternatives . . I still have a nozzle from a prior life
that is necked down to about 3/8" and is about twice as long as usual.

It also came with a longer center tip so it could still stick out . .
This would get you down in those deep corners and still give you the
ability to see . . 

Check with a local welding shop catalog and see what they have. . .
give you an idea of how to make one for your rig . . just slips over
your stock nozzle . . .

Gas pressure . . . inside in a corner, maybe 1/2 cfm  . . barely flowing . .
you have a fan on or working outside, may need 15 cfm . .

Average shouldn't be more than about 4 cfm as I recall . . 

Keeping all this in mind, lots of times it is in your interest to 
put up an air shield between the fan and your weld, just something low.

Spatter Shield: if you don't have some, get some . . it's a spray can
of some stuff that keeps the dingle berries from sticking to your 
nozzle or tip . . 

I will describe a good weldor on a job . . he taped a piece of mirror
inside a hole, then bent a welding rod into a hook, got in there and 
stood on his head and welded the backside of this boiler header that
was cracked . .  it was later x-rayed and found solid . .

While you can't get a mig gun in that hole he was in, there is no reason you
can't weld the back-side of things by looking in a mirror.
Well . . maybe one reason . .  :-)