Stainless and Argon?

[FarmallMan]

I have heard that 100% argon can be used instead of tri-mix when MIG welding stainless. This would mean that I could get away with having one less bottle around the shop, which is good because space is at a premium.

I'm aware that Hobart recommends tri-mix to help with wetting and to produce a flatter bead, but has anyone tried using pure argon? How did it work out? The welding that I would be doing on stainless wouldn't be on anything critical or on anything pressurized.

Nick

[weldgault]

when you mention mig welding, do you mean Short Arc, Spray or pulse. The gas used on these three would make a difference. John

[Rocky D]

I have heard that 100% argon can be used instead of tri-mix when MIG welding stainless. This would mean that I could get away with having one less bottle around the shop, which is good because space is at a premium.

I'm aware that Hobart recommends tri-mix to help with wetting and to produce a flatter bead, but has anyone tried using pure argon? How did it work out? The welding that I would be doing on stainless wouldn't be on anything critical or on anything pressurized.

Nick

I haven't tried straight argon, but I would think it would be hard to control, too wet, but it will work. For small jobs C25 will work too. Some folks say that Tri mix is nothing more that hype, however, that is all I have ever used for stainless. Bottom line...try it, you won't hurt anything.

[aametalmaster]

Straight Argon will let you weld SS but it dosen't wet out well and will leave a high big bead. I just use 75/25 i know its not textbook but it works and i have one less bottle sitting around that would prob hardly get used. If i was welding SS daily or parts that were critical i would use tri mix but my repair work 3 or 4 times a year the 75/25 gets used...Bob

[FarmallMan]

when you mention mig welding, do you mean Short Arc, Spray or pulse. The gas used on these three would make a difference. John

Yes, please excuse my ignorance when it comes to terminology and processes. All I know about welding, I taught myself. I once had "training" as part of a college class, but I would have to say that I knew more than the TA. LOL.

Anyway, that's a long winded way to say short arc.

I had read that C25 could be used, but I haven't tried it. A friend of mine (also self-taught) has used C25, but described it as being less than optimum. My only real concern with using C25 (which is what I use for mild steel) is that I have read that the welds themselves may corrode. One of the uses will more than likely be repair or fab of maple sugaring equipment.

Thanks for the input!

Nick

[aametalmaster]

I have welded lots of SS parts for my local resturant like ss tubs and such, just repair welds. No one ever complained about rust. I have some small parts i will weld and hang them on my garage so i can watch them in the outside world elements. I have some SS dog bowls i made from some 1/8 304 15 years ago and they are fine sitting in the yard...Bob

[FarmallMan]

Right on Bob, thanks for the info. You've eased my concerns.

Nick

[SundownIII]

If I was welding anything stainless for the food service industry, I would use tri-mix. Why go to all the expense of using stainless and then not weld it properly. Penny wise/dollar foolish.

There's a reason tri-mix is recommended for welding stainless in short circuit transfer, just as there's a reason for using Argon/and 1%/2% O2 for welding stainless in spray transfer.

[Big_Eddy]

I tried MIG welding 22 ga stainless with a 110V Mig and 023 wire using straight Argon, and it didn't work worth beans. Big tall bead sitting on the material with no wetting and no fusion. I tried again with C25, and while it wasn't beautiful - it was functional. Was just a short lap weld that I needed to stick together - didn't care about the stainless properties so did not bother to back purge.

[Rocky D]

Stainless if funny in that if you back purge, it will weld a whole lot better.

[SundownIII]

Rocky,

I agree 100% with the comment about back purging.

I guess I must be different from most. I was always taught and subscribed to the school of thought that "if something's worth doing, it's worth doing right".

Considering the cost of raw stainless today, the cost of a small bottle of tri-mix is in the noise level. Why take chances when it only costs a little more to do it right.

I've also listened to those posters who say they've been successful welding stainless with ER70-6 wire. Again I ask "WHY?"

[Bob S2]

I've welded a few stainless steel items with c25 using just plain er70s6 wire. Couldn't tell the difference between that and regular steel. It was several stainless hinges I welded onto a mailbox I made. No problem with rust after 3 years.

I understand the reasons against a tank of tri-mix, they are quite valid:
1) cost. A separate tank leased is probably $150 bucks or more by the time you've paid the deposit, paid for the fill, etc. That's a lot of money for something you aren't planning on using more than once every few months.
2) Space. I don't have much space, and if I had another tank, the only place it could go is where recylcing bins are, so where would I put those? There is no space for even one more item in the garage.
3) Need. Non-critical non-food service non-structural occasional items just don't require it. Sure it'd be great to have a separate trimix bottle but hey what do I care it's a mailbox and it's been fine for 3 years without rust on the hinge. So, clearly no pressing need for tri-mix.

Now, there are valid reasons why you would definitely want or need the tri-mix: Food service area, marine applications, or humid locations such as bathrooms/crawl spaces, etc. If you need rust protection on the weld itself, you need the right wire and the right gas. Its just not always needed even though you are working with stainless. Sometimes good enough is better than being out $150 to do it the 'correct' way.

--Bob