adventures in welding stainless

[jonp9576]

wow, great information. i am going to try that in the next couple days.

 

[2-0turbo]

Straight Argon is fine. Prep the weld zone with a new scotch brite wheel if there is scale/dirt to remove or clean... the important thing is the area is clean. 2% Thoriated Tungsten for your tig torch and you should be ready... just be carefull of warpage from to much heat in one area of the fitting being welded. Don't continuously weld a bead.. skip weld until the fitting is welded all the way around. I don't know if your going to gas back the inside of the keg with Argon. If not. use some Solar Flux B on the joints on the inside.

He is welding with a MIG setup. And unfortunately, with most MIG welders, you can get some welds that probably hold, but they are going to look bad. Your limitation is the wire size. You leave a bunch of variables out of your description. I've welded 1/4" SST with Argon filler and .035 filler. But, it looked terrible. I needed 0.023 filler, but I couldn't find 309 in the small diameter. TIG is really the only way to go, but the equipment is expensive and the learning curve steep. I think you said you're welding with a Lincoln 125 and .035 wire for SST on that is going to be too big. I was using a Hobart 135 myself and was not really satisfied. You'll be able to stick some metal together, but they are not going to look great. Good luck!

 

[hooks]

He is welding with a MIG setup. QUOTE]


He asked a question about Tig welding so I gave him info for that..Here's his question..

i am using stainless filler. i think it is 308. i'll try to get ahold of some 316. We run a compressed gas and welding supply shop here so i should be able to get it fairly quickly.


how do i clean the stainless before and after i weld it. i've read that regular samd baber s bad, and the same goes for grinding wheels.

i have a stainless wire wheel coming. is there anything else i need?



about gas...i was using 75/25 argon co2 for steel. for stainless i was told 100% argon so thats what i've been using. is there anything else i should try other than 100% argon? i can make just about any mixture you can think of since we sell it all here and i can blend it myself.QUOTE]

 

[jonp9576]

i am using a mig machine, not a tig machine. we only stock 030 stainless wire, but i can get any size. i'll order some 023 and see how that works out for me

 

[hooks]

Ooops sorry. For some reason I was thinking TIG.

 

[2-0turbo]

i am using a mig machine, not a tig machine. we only stock 030 stainless wire, but i can get any size. i'll order some 023 and see how that works out for me

Oh, if you can get .023, I think you'll find that will work much better on your (and mine) smaller machine. You can also try an Argon/Helium mix (like 75/25) that will give you greater penetration, which is nice for a smaller machine. It should also tend to flatten out that bead a little bit.

As others have mentioned, make sure it is clean and it should work fine. Good luck and post some pictures when you're done!

 

[jonp9576]

ok, sounds good. should i mix 75% helium? or 75% argon. helium i think, right?

 

[kladue]

That was 75% Argon 25% Helium, that gas combination keeps more of the heat in the weld area and will make the lighter machines work better. You should be able to use straight Argon as sheild gas, smaller wire will help also. As with all stainless cleanup, swapping grinding discs and wire brushes between carbon and stainless steel will give you rusty rewards. Even with careful cleaning the stainless welds can rust because the passivation oxide layer is lost during the welding process, using barkeepers friend after cleanup will help control the surface rusting until oxide layer rebuilds.

 

[jonp9576]

ok sounds good. i'll try out the helium mix and some smaller wire

 

[jonp9576]

so i didnt try stainless today but i did a bunch of welding on my brew rig. i tried higher temp amd moving faster. WOW. the welds look great and they are nice and strong. before with the lower temps i was laying down these big welds with minimal penetration. now moving faster with a higher temp they are almost flat. and i can stand on all three levels of my rig so if i weigh 280 i think it will hold anything i put on it

 

[imsoweetadid]

Make a thick slurry of the flux, paint it on the opposite side of the weld out to 1/2" from weld area to protect the adjacent metal. Instructions on can call for alcohol but water works well too, about 1 drop to the spoonfull works for a start. After welding the flux will fuse together and leave a glassy surface that will come off with a stainless brush on a 4" grinder. When making water tight welds check to make sure there are no flux pockets in the weld to break out and cause a leak, drill out the pocket and make a pass over the hole.

Im a welder by trade, and I never heard of mixing the flux with water. In fact, water will cause welding defects such as porosity, and cause leaks. If your using solar flux type B for welding stainless, go out and buy a product called HEET. They sell it in the automotive section in wal-mart. HEET is what your supposed to mix the flux with.

 

[kladue]

That is curious, I must be extremely lucky all those years then when using water with the backup flux on stainless pipe, the flux is used to prevent oxidation (sugaring) in adjacent areas when welding stainless, not in weld puddle. After you light up what ever water was used is gone in seconds as the heat travels ahead of weld area.

 

[jeff967]

Im a welder by trade

I am now retired, but stayed under a hood for 30 years, ASME pressure vessel certified.
and it is very common to mix solar flux with water or denathered alcohol.

 

[imsoweetadid]

I am now retired, but stayed under a hood for 30 years, ASME pressure vessel certified.
and it is very common to mix solar flux with water or denathered alcohol.

Really, that is interesting, this is a first for me. Water can contaminate a weld, thats why out at the ship yards we would torch heat the metal to be welded, to drive off the very visible water that is in the metal. Also adding water to the flux doesnt allow the chemical reaction to take place like adding Methanol/methyl alcohol would, but you know what I will try your method of adding water, next time I break out the tig, because hell, I might learn something!

 

[Homercidal]

Im a welder by trade, and I never heard of mixing the flux with water. In fact, water will cause welding defects such as porosity, and cause leaks. If your using solar flux type B for welding stainless, go out and buy a product called HEET. They sell it in the automotive section in wal-mart. HEET is what your supposed to mix the flux with.

I think HEET is just a form of alcohol and I believe that if you use it in welding, the purpose would be to help drive out any water moisture.

I have used it as fuel for a Pop Can Stove for lightweight camping (google pop can stove for more info)

 

[imsoweetadid]

I think HEET is just a form of alcohol and I believe that if you use it in welding, the purpose would be to help drive out any water moisture.

Exactly, thats why I cant believe you can mix the flux with water, kind of defeats the purpose, but I will try anything at least once.


By the way, that pop can stove is pretty neat looking, I will have to try it out.

 

[imsoweetadid]

ok sounds good. i'll try out the helium mix and some smaller wire

When you goto your welding supply shop, tell them you want Tri-Mix, that is the only mix I will mig weld stainless steel with, and is what someone mentioned a couple posts back.

 

[jonp9576]

we own the welding supply shop. i'll make the mix. what are the %

 

[imsoweetadid]

we own the welding supply shop. i'll make the mix. what are the %

90% helium, 7.5% argon, 2.5% co2 is what he's gonna need.

 

[jonp9576]

sounds good. i'll make that mix up this weekend and give it a try. i have an old stainless liquid oxygen container i am practicing on.

 

[imsoweetadid]

sounds good. i'll make that mix up this weekend and give it a try. i have an old stainless liquid oxygen container i am practicing on.

That mix is really good on thin metal, which the tank most likely is. Point being is that, this mix will work really well for you, and you will see a hell of an improvement. Tell me how it goes for you!

 

[jonp9576]

i tried it today. it seems to work fine. i think my technique is the problem. i still cant gat the welds to be concave. i could when i was working on my brew rig, but not with the stainless.

also, is this the stuff i should be putting on the under side of the welds? it said whire brazing flux for stainless and other metals between 700 and 1800 degrees

 

[jonp9576]

this is a pic of how thick the metal is that i am working with

its kind of hard to tell how thick it is, but its about double as thick as the top of a keg.

 

[2-0turbo]

Hey Jon, several of your welds are looking nice! What you've got there will certainly work. Or, keep practicing and they will look REALLY good after a while. The flux you've got is not what you want. That is for brazing. I honestly wouldn't worry about the flux. The only that that will happen is the inside of your weld MIGHT sugar, depending on how hot you're getting your item. You can just grind/buff it off in the end. The other route is back-purging. But honestly, this is too much trouble and I rarely do it, even when working with tubing. Just weld it up, clean the inside up if you need to (from the sugar) but I think you'll be fine.

Your horizontal welds on the left, the 2nd and 3rd one down look nice. For your vertical welds, starting from the left, the 2nd and the 7th are real nice. Try to stick with those parameters, travel speed, etc. If you can, try to position your piece flat so that you are welding like on the top of the table. This will let gravity work with you and improve your welding tremendously!

 

[jonp9576]

thanks for the tips. i really dont have a need to weld stainless other than that at some point in the future i would like to turn the rest of this old oxygen tank into a large conical fermenter. but for now i dont have the space for it or the brewing capacity to fill it. so i just want to learn to weld stainless just for the fun of it.

 

[jonp9576]

if i were to make the conical, i would buy one of these hoppers that are apways posted on here and weld it to the bottom of the open cylinder. if i do that, should i weld the inside so its cleanest on the inside, or should i weld from the outside. i was thinking the inside. do you get what i'm asking?

 

[imsoweetadid]

if i were to make the conical, i would buy one of these hoppers that are apways posted on here and weld it to the bottom of the open cylinder. if i do that, should i weld the inside so its cleanest on the inside, or should i weld from the outside. i was thinking the inside. do you get what i'm asking?

Now are you gonna tig or mig the conical? If you were tigging it, then you would fuse weld it from the outside, with the flux painted on the inside, and if you fuse weld it right, the inside should look seamless, with no gaps or cracks. If your thinking of mig welding the conical, well I will to you not to, unless your mig welding on stainless steel is top notch, and you know what your doing. One because mig welding conicals to be sanitary are not usually done, unless done by robotic welding, and two, its hard for someone starting out welding to weld such thin metal without defects, making your conical prone to bacteria in those weld defects, which some are, and are not visible to the naked eye. That flux you had is the wrong flux, you need a special flux for stainless steel, called solar flux type B, and mix it into a thick paste, and brush onto the back side of the weld. This will protect the backside from any sugaring.

 

[jonp9576]

ok, so lots more practice before i even consider mig welding the fermenter.

and i will look for the solar B flux. i have seen it in our shop before i know we get it in once in a while.

 

[imsoweetadid]

ok, so lots more practice before i even consider mig welding the fermenter.

and i will look for the solar B flux. i have seen it in our shop before i know we get it in once in a while.

Also I should tell you solar flux isnt cheap, at $45 for a one pound can, but it goes a long way, as you only need a little at a time. Also a product called heet, is what you mix it with, but someone here said you can mix it with water, but Ive never tried it that way. I just followed the manufacturer's suggestions and guidelines, and it has worked great.

You should make a mock fermenter, by just placing two similar thickness materials together to form a butt weld, and run welds along the seam around 2 inches long, to get your heat right, and to make sure your getting good fusion all the way through. Also run the welds in the flat position which is easier, and is how your gonna run the welds on the fermenter, because the fermenter is manageable, and you can position it anyway you want. In shipyard work, we weld in the flat position whenever we possibly can, because its fast and easy, but when you get on the Navy ships, you have no way of positioning the ship the way you want it to weld flat. Another thing, dont compare, or try to get stainless steel mig welds to look like mild steel mig welds which lay flatter. Stainless steel mig welding, run at the right amperages, and wire speed, tend to be more convex than mild steel mig welds which is normal. So dont try to get Stainless Steel mig welds to lie flat, by turning up the amperage, because it will do more harm than good.

By the way, even though I weld for a living, I would love to work in a welding supply store. I would never have any money each payday, it would go all back into the store for equipment, and gadgets!

 

[BrewBeemer]

Also I should tell you solar flux isnt cheap, at $45 for a one pound can, but it goes a long way, as you only need a little at a time. Also a product called heet.

By the way, even though I weld for a living, I would love to work in a welding supply store. I would never have any money each payday, it would go all back into the store for equipment, and gadgets!

I have used 99% rubbing alcohol from WalGreens, cheap and works.

Welding supply stores especially when a new model welder or hood becomes available always made my credit card jump out of the wallet out of control many times years ago. My LWS was always good to me with freebies on materials as I did free electrical side jobs, wired in their customer test welding bench power.

I just got happy with my new to me toy two years ago a Hypertherm Max 20 slightly used for only $125 (had to buy it even when the Miller 375 was on the wish list) my friend comes to the shop with his laser cutter. Damn him what a tease.

I find back gasing plus adding a 3/8" thick x 3" wide copper plate that's preformed allows for using more heat and moving faster on Tig welding coupling to kegs. The couplings are machine stepped down a little on the end plus a tight fit with the excess inside the keg ground flush to the kegs internal radius. Second pass just a fusion weld on the inside over the inside joint. Tight fit is good (keep it clean thinking) as stainless isn't like a muffler shop to pile on the filler closing large gaps. All in the prep makes Tig less of a challenge, didn't say easy especially when away from it for 8 to 14 months on the mend.