MIG or TIG??

[mike os]

been asked to make some frames to hold awnings in stainless, & wonder if i can get away with using a mig ( stainless wire & argoshield light) or am I better off just biting the bullet & getting a "cheap" (ie£ 5-600)TIG & doing it "properly"

Appreciate weld appearance will be better with tig, but can I achieve a satisfactory finish with MIG? ( yes I can weld mild to a suitable standard )

 

[Luke]

Stainless MIG is ok with the right wire and gas and can be cleaned up to a decent finish, it's just slightly more hassle than a TIG weld, which is more aesthetically pleasing to start with.

I'm guessing the frames are reasonably substantial, so no issues with thin material etc?

 

[Country Joe]

Truth be known, I've not done much with stainless wire - a couple of beads with someone else's welder & wire, just to see if it seemed much different to mild. It didn't, but then he'd done all the setting up.
Anyway, I imagine you can always tidy it up afterwards, if needs be?
Don't know if it'd be worth it for a one off, but you never know - you may end up using the tig quite a lot, after this job too?
All the Best,
CJ

PS I think Luke got there first!

 

[mike os]

clean up should not be a problem, but corrosion resistance could be.....so need reasonable control

as long as I can get reasonable beads & not too much discolouration I will be happy.

if it discolours can it be cleaned chemically rather then mechanically?

 

[Hitch]

You may well be better off with a gas such as stainshield if it is important.

Cleanup wise, you can chemically clean the are with a pickling paste, such as Avesta or Pelox.

Mig welds tend to take a bit more time than tig welds to clean, especially if you went down the argoshield route.

 

[hotrodder]

Yep, pickling paste is the usual method when corrosion resistance is important. More info here here.

 

[mike os]

thanks guys

wheres the best source for 15kg rolls of wire?

 

[backpurge]

Mike
Don't even consider using Argoshield Light, you will end up with a heavy carbon coating due to the 5% CO2 and 2% O2 in the gas also the weld doesn't tend to sit flat. You will get a far better result using either 2.5% CO2 in Argon or Stainshield as mentioned above. Get your voltage up and travel faster than with mild steel.

Personally think TIG would be a better option,it's going to look a lot neater and by the time you've finished fettling the MIG welds, it will probably be quicker as well