# Forum Home Renovation Metalwork & Welding  Using mild steel gas for stainless mig welding?

## PlatypusGardens

Been wondering about this as I'm thnking about venturing in to the stainless realm for some of my garden ornaments etc. 
Seems to depend who you talk to really.
On of my mates dad reckons he gets better results with mild steel gas when welding stainless while others say it's a big nono. 
 (This is with using SS wire BTW.)    :Confused:

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## Uncle Bob

IMO, If you have TIG, use it (with Argon of course). Once you master it (and it isn't that difficult, unless you're trying to weld Ali), your MIG torch will end up gathering dust.

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## Marc

Mm ... dunno about that. MIG and TIG are two different things and each has it's strength and weakness. I would say that TIG excels at SS and Aluminium but it will never replace MIG for general metal work. Way too slow and awkward.
You can replace MIG with a good rotary stick welder and a lot of experience though.

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## PlatypusGardens

So.....back to the original question....    :Smilie:

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## Marc

Question? What question?
Oh, yes, haha
MIG welding SS, you need SS wire to begin with (rather obvious) 
Gas, if you going to weld SS day in day out, get yourself a helium argon co2 tri mix, welds hotter and compensate for the colder welds with SS.
Otherwise Argon O2 98/2 will do fine.
All of this is necessary to keep your weld rust free. If you on the other hand only want to weld something together. just use your normal set up. The weld will distort more than normal and the weld will not be stainless.

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## PlatypusGardens

Yes I have the SS wire.   :Smilie:   
But....with SS wire and the "wrong" gas the welds won't rust....will they?
(that was the question  :Wink:  )   :Confused:

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## Marc

Depends what SS and what gas.
In general, yes, and each type of SS needs in theory a different gas.
Tri mix is good for austenitic SS call it 304 or 316 and the rest in between, 400 series needs a different mix again
The problem is that SS is SS only because of a thin layer of oxide that protects the metal. Excess O2 will affect this layer and make the steel more prone to rust. 
However like everything it is a matter of degrees.
If you are welding a 316 acid tank, I suggest you get your self helium mix, if you are welding together two pieces of scrap SS you don't even know what grade they are, and it is for decorative purposes, I would weld with ordinary mig wire, polish with a brass brush and leave outside and see what it does. 
I like to forge SS because it turns different shades of gold and brown even when it does lose some of the stainless quality's.

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## PlatypusGardens

Well yeh it'll be pieces of scrap SS.
So I won't really know which grade, by number, it is.   
I'm not about to start building high pressure tanks or truck bullbars any time soon. 
Well, I'll give it a go and see what happens I suppose.       :Smilie:

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## Marc

Give this link a read, tells it better than me.
Another link says tri mix gases with helium are BS and that argon 98/2 or 97.5/2.5 co2 are the go. 
You can always test SS with a magnet. No magnetic, it is 300 series and you use argon 98/2 co2    Welding Stainless Steel

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## Marc

Platipus next project

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## PlatypusGardens

> Platipus next project

  
Yeh mixing rust and stainless looks good.
Trying to stay away from the more typical things like geckos, frogs etc but I do like the one in the pic there! 
Will have a look at that link too, cheers.     :Smilie:

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## Marc

SS MIG with c25 gas question 
More read on a welders forum about welding SS with different gases. 
It seems the consensus is 98/2 htre too. They mention tri mix as the "right" gas though, others frown upon it and go for 98/2. From what they say, c25 would make the weld rust.

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## PlatypusGardens

I wouldn't even know what kind mine is....
This is what it says on the invoice    
And on the bottle

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## Marc

18 is for CO2, the rest is argon so 82/18 argon CO2 . Too much CO2 will stuff up the Chromium in the SS alloy and make it rust, but by how much is the question. I would try, rather than buying another cylinder. Did you buy that one or rent it?

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## ringtail

Same gas as mine. Corgon 5/2 it's called. You must rent from aitken welding ? Re your question, i would buy a cheapo inverter stick/scratch tig. Cheap as,perfect for SS as HF is only required for ally. Just leave it set up for SS full time and let the mig do what is does best.

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## PlatypusGardens

Yeh I'm on the Blacksmith Jack's rental for the bottle at the moment but am gonna have a look around town and see what the go is. 
it's costing me $60/quarter for rental and $99 to refill at the moment.
Has to be a better deal out there,
Just been too lazy to go looking. 
Only got the bottle rental from BSJ as that's where I bought the welder.    :Smilie:  
Will experiment a bit with gas flow and see how it goes.
Not too keen on forking out for another bottle just yet.
The SS wire is exe enough as it is.
I got a 1kg roll for $35 and that was half price.... 
Actually that's also something I need to do a bit of Googling about and see what bargains there are to be had on the WWW.     :Smilie:

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## PlatypusGardens

> i would buy a cheapo inverter stick/scratch tig

  
My welder does all three.     :Smilie:

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## ringtail

I'm the same with gas. Ran out 3 months ago and am too lazy to get it refilled  :Tongue: , despite paying rent on an empty bottle. The depot used to be 5 mins from me but got flooded hardcore in 2011. The have now moved to down near the airport so it's 1.5 hr return trip and they don't  deliver to any businesses over my way. Bugger. There are deals out ow where one buys the bottle outright for about $200 and then just a phone call will see gas delivered to your door swap and go style.

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## Marc

I bought argon cylinder from Speedgas, so no more rental, refill is dearer than boc gas though. If you use more than 3 or 4 cylinders a year, you are better off renting, if you like me only use 2 a year you are better off buying your own and refill when you need it. 
About gas for SS, the question is ... and I don't know the answer ... will the 98/2 mix be ok for aluminium? If so, you have two birds with one stone. If you can only weld alli with pure argon then ... bummer.

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## PlatypusGardens

I seem to go through 3-4 bottles/year.
Usually almost on par with a 5kg roll of wire.  
Just spoke to ol mate earlier and he reckons he's never had any trouble with mild steel gas and SS wire.  
Aloominum is probably a different kettle of fish tho.  :Smilie:

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## Normanby

A few weeks ago I drove to Mackay Total Tools who have recently become distributors for Power10 gases argon and argon mix gases. I bought an "E" argon for aluminium and may possibly buy an argon mix later when I need a new one. This is to get away from ongoing cylinder rental. 
The current prices are:
E size New $479 and refill $159  for both Agron and argo mix 
D size New $339 and refill $99  for both Argon and argo mix 
Probably not as cheap as in the larger cities where there is more competition. 
I live approx half way between Mackay and Townsville but have not found any buy and exchange welding gases in Townsville although Total Tools there are considering offering this service. 
Still about a 250 Km trip each way but no other option for purchase closer right now.

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## Marc

Where to Buy Gas Cylinders in Australia | Speed Gas

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## PlatypusGardens

> Where to Buy Gas Cylinders in Australia | Speed Gas

   :Roll Eyes (Sarcastic):

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## Marc

mm ... leather apron ?

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## PlatypusGardens

I love how there's a bloke half in the background of the first pic.   :Rofl:   
Anyway, the closest to one to here is Gympie and that's still almost 1000k away...

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## Normanby

I sent an email to Speedgas regarding agents in NQ and received this reply on 6/3/2015. 
"I'm sorry but we don't currently have any distributors in North Queensland. 
Kind regards
Speedgas" 
Maybe they will have one (or more) in the future.

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## Marc

May be you are better off renting if that's the case. No point buying a cylinder that no one wants to refill

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## PlatypusGardens

I had a go at this the other day.
Will be interesting to see what happens to the welds now.   :Smilie:

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## Marc

How did your SS weld turn out?

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## PlatypusGardens

Part from lots of spatter at the time, they still looked stainless last time I checked  :Smilie: 
Will have a closer look later.  
Should put it out in the weather as it's drizzling a bit today.  
We need Grahame to chime in here actually.   :Biggrin:

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## PlatypusGardens

Some rust appearing around the welds, but the welds themselves are still clean.    :Smilie:

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## oldtrack123

> Some rust appearing around the welds, but the welds themselves are still clean.

  Hi 
It will be the heat affected zones adjacent to the actual welds that are most likely to be the problem
 Rusting & hardening/cracking due to the formation of chromium carbide [ that is if you used a high co2 mix gas]
Argon/02  is a good all round gas for Stainless ,Helium is mainly a American gas ,simply because they have good natural sources[gas fields]

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## PlatypusGardens

Yeah might have to bite the bullet and get a small bottle I suppose...  
*sigh*

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