Migging stainless

[KemppiFrog]

Need a little advice here... So turning to you more experienced guys on here.

Need to get a railing up by Friday. Tube is 304 40x40x2, 30x30x2 + verticals in 20x20x1.5.
So, phoned around for argon + 2% CO2 gas for my mig with 308L 0.8 wire. Nobody has any gas in stock. Choice is the argon+ 8% CO2 I have, or straight argon. I tried a few beads with the 8% and pickled them. Don't look too bad.
Any thoughts on this?

One supplier offered to change my mid size bottle for a big one with the 2% mix; But that causes problems with my contract and is very expensive, as it seems they charge over double for the 2% mix as there is little demand ?? ( I suppose all the SS guys use TIGs) As the job has not a lot of margin, the bigger bottle option is not cost effective. BUT, I don't want to piZZ off a possible good client, despite the short notice.

 

[TechnicAl]

The 8% should produce blackish oxidised welds and the argon will make peaky shaped beads

If you pickle the oxidised welds they should look ok and be fine with normal atmospheric corrosion

 

[KemppiFrog]

Thanks Al, I wasn't quite sure what the effect the argon wouild have on its own.

 

[Mr shiney]

I just use Argoshield lite when welding stainless. Gives nice welds requiring little clean up. Not sure what that mix is?

 

[Jan]

I just use Argoshield lite when welding stainless. Gives nice welds requiring little clean up. Not sure what that mix is?

There's a question mark as to the constituents of Argoshield Lite. Many say that it's 93% argon, 5% CO2 and 2% O2. However my Volkszone cylinder is marked as "UN 1956 argon, carbon dioxide" with no mention of oxygen.

 

[hotrodder]

There's no question mark over the recipe for argoshield light, it is 5% CO2, 2% O2, balance Ar...
http://www.boconline.co.uk/internet.lg.lg.gbr/en/images/Argoshield-factsheet410_54556.pdf and https://www.boconline.co.uk/internet.lg.lg.gbr/en/images/argoshield-tg-9600-mixture410_87458.pdf

With regards to stainless TechnicAl covers the correct gases in the welding other steels section of the tutorial. Also https://www.boconline.co.uk/en/prod...shield/argoshield-light/argoshield-light.html, which like other gas companies says

The oxidising potential of this mixture has a tendency to produce welds with a black surface film. In many stainless steel applications, this type of surface finish would be considered unacceptable and removal of the surface film would be required. Cleaning away this residue can be both time-consuming and costly. Due to this, other products such as the BOC Stainshield range of gases would be recommended.

and

Please note:
Argoshield Light should not be used for welding stainless steel or nickel alloys because carbon from the shielding gas will be introduced into the weld (carbon pick-up). For these applications, BOC Stainshield Universal is suitable

The Ar + 2.5% CO2 mentioned in the tutorial... in BOC speak this is one of several flavours of 'specshield'. Details and available cylinder sizes for all the different flavours are here http://www.boconline.co.uk/en/sheq/product-factsheets/product-factsheets.html

 

[Paul.]

All the BOC Argoshield mixes contain 2% O2, UN1956 is a hazmat classification for non flammable compressed gas
Its in all the MSDS
http://www.boconline.co.uk/internet.lg.lg.gbr/en/images/argoshield-tg-9600-mixture410_87458.pdf

 

[Kent]

Have you looked at the viability of doing it TIG with a scratch inverter, it will save on a reel of wire (dependant on amount of work / time)

 

[KemppiFrog]

Thanks for the replies. Railing is fixed in place and client happy. While a Tig would have put nicer welds, the Mig with 8% CO2 did the job OK and cleaned up with pickle. I did have a scratch start Tig/ Stick unit, but it went phut and since I mostly used it for stick, have not replaced it yet, as I have a decent stick unit. Bear in mind that the order only came in early this week and fitting was Friday, so by the time I found that the 2% CO2 mix was not available, options were limited. But, since the same client might want a 17 mtr pool security fence ( legal requirement here) I might look into a Tig set. Second hand market here is expensive and sparse, which leaves me with chinese of varing quality. Leaning towards the German outfit that Norlander bought his plasma from. Decent guarentee

Kent.. Not short of mig wire in 308L or 316L; Two full reels of each.