Don Foreman wrote:
Interesting, Grant! I have similar background, use a slightly
different approach though the underlying processes may be similar.

Sit rep: after consulting with Ernie, a Millermatic 210 MIG machine
followed me home last week. I've had a Lincoln SP125 small MIG for
years that works beautifully with sheetmetal, so I thought I knew how
to MIG weld. WRONG-O!

Current project is mostly fillet welds with 1/8" wall thickness steel
rectangular tubing and angle, easy peasy with stick. Built lotsa
stuff like that with a buzzbox and 7014. I was gonna stickweld this
project but then....

I had a windfall patent check in my jeans and my attitude has always
been to blow those on toys as quickly and frivolously as possible --
welcome to your new home, Mr. Mller 210.

I got servicable(?) welds at first but I was not at all satisfied
with them. Ugly! Ernie had endorsed the 210 as an "excellent
machine" so I was sure that the fault had to be mine. (It was.)

I bought the MIller MIG book, paperback, $28. MIG for dummies.
Miller could use an EE proofreader, but it's a welding book so
nevermind that. I read the book from cover to cover in one sitting.
I didn't just read it, I studied it. I learned that MIG ain't as
simple as it looks. There are a lot of variables with various
interdependencies that aren't always obvious and are sometimes even
counterintuitive.

I then let things ferment for two full days without touching the
machine, to let the subconscious do what it does however it does it.

When I again approached the machine I found that I did so with
considerably more confidence and a better understanding of what I
might do beyond set the dials per the chart, cross my fingers and have
at it.

I dialled my mask back to shade 9 because I realized that I hadn't
been seeing the puddle. I bumped the voltage up one click from the
chart setting and I knew why I was doing that. I clipped the
stickout to a short 3/8" and proceeded with the gun angled so it
pointed in the direction of progress -- and I knew why I was doing
those things too.

It worked first try! I got very nice flat fillet beautywelds just
like the samples in the welding store. YAY!

----

One thing I learned that I found useful, YMMV: With gas (O/A) and
TIG I can manage the puddle, controlling heat input independent of
rate of filler metal deposition including zero deposition rate. With
stick I sorta manage the puddle because I usually run the rod at
whatever current it likes best so operator input is to drive the
puddle.

With MIG there are more variables: stickout, voltage, and current
which is essentially wirefeed rate for given wire size. I think with
MIG I respond to the puddle more than managing it. The voltage and
wirefeed rate are set before the mask goes down and the trigger is
pulled. After that, all I can do is steer -- and it's a bit hairy at
first because things go fast. It sure is fun when ya get it right!

I've found distortion to be less of an issue with MIG than with stick
though minimizing it still requires some planning and jigging.
The L-shaped cantilever workbench supports I'm making are so far
coming out very nearly blackout square, 3 out of 5 done. No
spatter, no smoke, no slag-removal, no grinding, no mess and no
hydraulic tweaking to square. I think Mr. Miller210 and I might
become good friends bye and bye.






On Sun, 15 Aug 2004 09:32:03 -0700, Grant Erwin
wrote:


This isn't a posting about a problem. It's a posting about how I think.
I had a problem with one of my machines. I couldn't figure out what to do
about it. After a couple of days worrying away at it I got the idea to
write it up like a posting to this NG and then put it down and read it
fresh the next morning. Sure enough, when I read it like the problem came

from someone else, laid out clearly just the way I like it, the solution

immediately came to me!

I think better when faced with a problem which is written out logically.
This is what happens when you take a guy whose background is mathematics
and electrical engineering, with a lifetime of education, and put him in
a machine shop. I bet if I'd started out as a machinist's apprentice when
I was 18, at my now-ripe-old-age of 51, I'd think better when presented
with a problem on the fly, on my feet, in the shop.

Go figger.

Grant Erwin


Good to hear youve made good progress with your mig welding.
Anychance of some info from you? what gas are you using?
Here weve used co2 and results are sort of ok. However having tried
co2 argon mix the results are so much better.
Have you tried this gas mix?
Ted Frater Dorset UK.