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Rossluck
28th May 2006, 12:56 PM
I have a question, mainly for Grahame Collins. Can you use copper-coated mig wire as a filler when using a tig on steel?

Edd
28th May 2006, 10:59 PM
Yep, you certainly can. It works well with thinner steel <1mm.

Rossluck
29th May 2006, 06:45 AM
Yep, you certainly can. It works well with thinner steel <1mm.


Thanks Edd, I couldn't see why not.

Grahame Collins
6th Jun 2006, 08:50 PM
Hi Ross,
Sorry I missed your post last week, I had not been online at that time.
It is a yes and no answer dependent on what thickness and shape you are welding.
Mig wire contains a great deal of maganese and other high strength materials. On lower tensile materials of minimal section section ,undesribale results can occurr.
When used on very thin mild steel -such as you could be welding typically with a Tig process- you may risk distortion and shrinkage, out of proportion to the volume of welding you have completed.
The dimensions and shape of the weldment will also have an effect on the distortion factor.
Remember, as with any other fusion welding process get the piece fully tacked up before the welding begins and try to place the weld beads opposing each other,so the stress from each one counter acts its opposite number.
Something with a long narrow shape with minimal thickness may distort beyond your expectations where something thick and block like may have no discernable distortion what so ever.
Hope that helps

Grahame

RUSHY
9th Jun 2006, 06:38 AM
HI Guys tig wire is double de-oxidised if you have mig wire that is de-oxidised then it is ok if not get a few sticks from your local welder or use stainless mig wire.

Grahame Collins
9th Jun 2006, 07:53 AM
Some one is bound to ask this.
The difference between double and triple de oxidised wire is in the consituent elements. Silicon and maganese for double deoxidised and the addittion of aluminium to the other two already mentioned to make up triple deoxidised wire.

These metals scavenge the molten weld pool to attach themselves to the nasty bits that are not desired and float them out to the surface.They are chipped off as a glassy scale slag particularly evident in the Mig process.

To avoid more nasty bits than you can possible handle, it's a good practice to use stored clean wire not stuff that been left around with rust beginning to break through the copper coating.Clean, prepared parent metal also goes along way to a sucessful outcome

A length of capped PVC tube makes an excellent filler wire storage facility.

The problem with mig wire is that it is left unprotected from the elements in position on the machine for long periods of time. When finally used it will deposit much of what has settled on its surface including rust and other airborn surce dusts and contiminants into the weld pool.
You would be surprised where the dust of angle grinders will settle and the unsuspected problems it can cause.
Grahame

Rossluck
9th Jun 2006, 06:38 PM
Thanks very much for your replies. I bought some filler wires at some stage in the past and was told by the salesperson that I'd best use them quickly because they start to surface-rust and become relatively useless as soon as you open the bag . I thought that the copper coating on MIG wire might overcome this. Your responses will take some time for an amateur like me to digest, but I get the picture in an overall way.

My welding knowledge is building, but the skill is still held back by impatience. I hold the handpiece or electrode holder like most people use a hose when watering a garden. The final result is a mystery, only revealed to me when I take the helmet off! :o