#mill sheet weld ..help required from MIG masters!

[NewLou]

Gidday :D

We been doing a bit of sheet metal work lately anywaz to cut a long story short after I jumped thinking our guillo got a hold of me after my off sider suddenly decided to change routine (Hands......whatch out................suddenly changed to the guillo flying into action without warning) we got a critical cut 9mil out! on some sheet metal bending work!

Luckily we finished our 1st job hassle free and was able to use this as a template to get all the angles right for a Tack up. We successfully got things micky mouse n tacked up ready to weld.

Shes about 2 meter square of 3mil sheet (Top of a bin hopper I think...................folded into place on the pan brake at work)

Anywaz wanting any tips u guys a got to reduce reduce heat buildup and distortion ........................

So far were gonna use as many clamps n cleats as possible n skip weld to reduce distortion .................

I'm pushing for attacking the weld which is basically a 3mil outside corner in dip transfer on the MIG but me off sider wants to go hotter (Lower end of Glob) Also wanting to let her cool naturally at room temp (Normalise)

Any hints for avoiding cold fushion and reducing heat / distortion really appreciated!!!!!

Not much room for error on this one so any advise from the Mig gurus out there really appreciated!!!!


Regards Lou :oo:

[Grahame Collins]

Hi Lou,
As voltage climbs (dip transfer to Semi globular) so does heat input and therefore the likelihood of sheet distortion.
Yes cleats and clamps will help -Ah Hah! you have been reading the Lincoln book then?

Grab some scrap and do some test pieces to prove to the offsider that this will occur.
Also I would be looking for ways to remove heat as soon as possible from the sheet.
Other wise, you know the drill, short runs, opposite side welding -spread the heat to make opposite forces work against each other

A hose set on spray after a short run to cool the heat affected areas down
or a rag dipped in a bucket of a water.
Even a copper chill bar clamped behind the weld area.
yeah!,yeah! , I know everyone does not have copper chill bars handy.

Being a packrat I pick up homeless bits of thick copper for that very reason.

Speaking of packrats, I am about to be press ganged into a pre xmas visit to the dump, at this very moment by her indoors and my son ( I really think blokes should stick up,a bit more, for one another ) demanding a cleaning up and willful wastage of "good stuff" I may need one day.

Being carried off from here kicking and screaming
Have a good Xmas everyone
Grahame

[NewLou]

Hey Grahame

Me and the offsider went for heaps a cleats n clamps skip welding on face n underside after much harrassment finally got him to go Dip (he went a lotter hotter than i would have but seemed to work fine) and cooling off the welds with a wet rag.

Worked a treat with the result being minimal distortion.........

We also decided to use thinner Migwire to further reduce heat input was fun to pull of the job effectively n get the shop foreman off our backs! thanks for all the advise which contributed to a job well done............

How many volts/amps would you have gone with on this one theres was much debate about the merits of reducing heat at the price of penno I was initionally thinking of going with about 14-16 volts.....................would be interested in your thoughts on this one

Now if you were only there when i jammed the punch after getting the taper wrong on the recieving cup :oo: whilst doing a heap a cleats on the punch n sheers ...................

Was lucky to come up with a workaround:wink:

But thats another story.......................

Regards Lou :2tsup:

[Grahame Collins]

I am happy to hear all has worked out for the best.

You only jammed the punch.Well I went further than that. In the early part of my apprenticeship was asked to change the punch and die to another size. Placed the die in upside down.

New boy in a new shop.Not told zip about punches. I must have been away they day they did punches at college. Kaaabang broken punch and ruined die.Result usual rev out and comments about don't they teach this to you at college type thing!

A week later in the same machine ,the boss a length of mis marked high tensile through it. Yup! he broken the punch and cast iron body of the machine.

Knowing when not to be a smart rrs I keep silent after the crash rang around the factory walls.
Good one Merv, I thought didn't they each you this at college.
The old ruined belt driven Asquith iron worker was replaced with something more in tune to the 20th Century.
They then took the time to explain the ins and outs of the system this time though..

Mistakes are one of things we learn from.
Grahame