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tacking stainless steel with a Mig
blakep82 - 22/10/10 at 01:20 PM

just going to tack some things together for checking it all fits, before giving it to a welder to Tig weld it all together.

i'm only going to be using mild steel wire to tack it, no point really getting stianless wire for such a small job, but do i still need argon? i tried tacking using mild steel wire and co2, and the welds just fell apart when i moved it, but it was outside, and it might have been a bit breezy out...


CNHSS1 - 22/10/10 at 01:25 PM

ive used co2/argon with mild wire and its fine. Windy day is probably the main cause though


blakep82 - 22/10/10 at 01:32 PM

quote:
Originally posted by CNHSS1
ive used co2/argon with mild wire and its fine. Windy day is probably the main cause though


that and maybe being lazy and shutting my eyes instead of using a mask... i'll give another go in a bit, but i'll find the small argon cylinder i've got somewhere


Dangle_kt - 22/10/10 at 02:06 PM

it should be fine, not perfect, but for tacks that will be taken off, it doesnt matter.


40inches - 22/10/10 at 02:28 PM

quote:
Originally posted by blakep82


that and maybe being lazy and shutting my eyes instead of using a mask...


Are you craaazeee


blakep82 - 22/10/10 at 02:41 PM

quote:
Originally posted by 40inches
quote:
Originally posted by blakep82


that and maybe being lazy and shutting my eyes instead of using a mask...


Are you craaazeee


yes. was literally only like 1 second, for 3 tacks. been watching too much american hot rod i think...


dhutch - 22/10/10 at 03:09 PM

quote:
Are you craaazeee

I know boat builders who have been doing this for 40 years. Practically standard procedure from what ive seen!


Daniel


trikerneil - 22/10/10 at 03:10 PM

My Missus spotted the tack welding with eyes shut thing on American Chopper last night and quizzed me about it.

Obviously they have never had arc-eye.

Neil


blakep82 - 22/10/10 at 03:41 PM

nope^ and neither have i

just had another shot, in the garage, with the mask, and the power up a little, and its seems to work, and fits!
when the exhaust goes down the tunnel its only got about a quarter inch either side tot he tunnel and gearbox. should keep inside nice and toasty in the cold weather... plenty of exhaust wrap needed i reckon

ok, not perfect, but i'm no welder
Description
Description


[Edited on 22/10/10 by blakep82]


AdamR - 22/10/10 at 03:59 PM

I've done quite a bit of stainless welding with MIG, and it works fine with argon/co2. No need for pure Argon. I've even tacked using pure co2 - no probs at all for tacking.

See pics of my headers in photo archive for the results.

[Edited on 22/10/10 by AdamR]


caber - 22/10/10 at 05:02 PM

Using mild steel wire on stainless that someone else will TIG is not a good idea. It will be a complete pain to TIG over and get a good weld! The tacks will need to be ground out completely to get a good finish otherwise you will get bubbles and all sorts of nastiness.

Caber


Davey D - 22/10/10 at 08:01 PM

Also if you cant grind out all of the mild steel before welding you will always get a little rusting in the place where you tacked it

[Edited on 22/10/10 by Davey D]


chunky2772 - 22/10/10 at 09:19 PM

im a st/st fabricator mate i make hand rails tables ect, i always use pure argon. you can use other gas mixes but you will get a different level of penatration if you tack mild steel to stainless you will always get rust spots on it dont forget condensation builds up on your headers when youve just started your engine your exaust will also spray droplets of water from the end of the exhaust pipe this is the build up of condensation inside the exhaust!

[Edited on 22/10/10 by chunky2772]


blakep82 - 25/10/10 at 11:36 PM

ah, so wasn't a good idea then? too late, but i guess if i get sports of rust later, a wire brush will take care of it, then weld again if need be? i don't know. i had to tack it somehow before having it welded


NS Dev - 28/10/10 at 07:22 AM

it all depends on how much of a perfectionist you are being.

I have done exactly what you show above, numerous times, and to be honest on 304 stainless manifolds the whole lot goes so brown after a short while you'll never know.

Also, if it froths when tigged up there is some crap in there, I've always managed to melt the mild steel into the tig pool without any issues at all.

Then again a mate who does a lot fo tig work always curses mild steel work citing froth as an issue, and I hardly ever have any problems. I think rod quality helps a lot, as does prep and cleanliness.

Blake, don't worry, it'll be fine