adventures in welding stainless

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jonp9576

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i've been using a stick welder for a few years here and there. i am not good, but not terrible.

the other day we got a mig welder. oh man is this thing fun and easy. i used it to finish up me brew rig.

then i decided i want to try some stainless so some day i can get my sweet conical fermenter project under way.

this was the mess that happened.
Apr17_0003.jpg

Apr17_0002.jpg

after burning through trying to weld 2 pieces together i just tried laying a nice bead down on one piece. i think i am getting the hang of it. a little
Apr17_0004.jpg


comments?
tips?
different things to try?
 
I've never welded Stainless but if I were to comment as a mild steel weld, I would say too much feed or to slow travel. From what I can see it looks like the edges bonded so the temp is probably correct.
I would stay away from welding tubing until you become proficient because you cant get to the inside for cleaning.
 
Welding stainless is a lot like welding mild steel. Looks like you have the feed up way too much or you're traveling too slow. Are you using argon?
 
thanks for the input everyone. i was only messing around with the tubing because it was laying around here i figured i would give it a shot.

yes i am using argon.


as far as the feed speed goes. i have found that with the stick welder i can control me speed and leave a nice bead. with this mig, i feel like it is rushing me. do i need to turn the feed down, or move faster? maybe a little of both.

i was getting "big" welds like this when doing steel too. instead of a flattened stack of coins it was looking like a stack upright. tips? links to a good video online?
 
turn the feed as low as it goes, and run a couple of beads. You'll know whne you want it to go faster. Turn it up until you get it set where you want it. Once you use it a bit more, you'll be able to crank it and move quicker.

B
 
I do pretty well with regular stick or wire feed on normal steel. I am using a Lincoln weldpac 100 with the MIG set up. When I got ready to make my keggles, I got some tri mix and started to practice on some 22 gauge stainless sheet metal that I had. I felt I got the hang of it pretty good. So, I drilled my holes, polished everything up, cleaned it, solar fluxed the back side of the weld, and tacked the couplings in. All went well, until, I burned through. I stitch welded, cleaned as I went, you name it. It still took me forever to get it to seal off. I'm not sure why, but the metal was cracking. I finally got it. But man, is it UUUUUUUUGGGGGLLLLLYYY! I did find that I felt like it was rushing me also. I like to weld a little on the hot side. As you've seen, stainless will stack up on you pretty quickly with the mig. Try turning your heat up a little and move faster. If your welding on kegs or any thin stainless, it's not like regular steel. I wouldn't try to get a "normal" looking bead, go for penetration without burning through. I have a high frequency tig box that the guy that I bought my welder from gave me. If I keep messing with this stainless, I'm going to have to hook it up and maybe take a couple of night courses. Sheesh, the things we do for brew! Luck - Dwain
 
I am a welder by trade, pipeline and compressor station work is my usual bag. Mig welding stainless is not the perfered method (tig or heliarc would be) but is more than sufficient for this application. One thing that will help is to match your filler wire to the base metal, ie 304, 308, or 316 or what ever it is. If you cant find out I would use 308 or 316. You can weld the lesser alloys with higher alloy filler wire but it wont work very well the other way around, cracks. One thing that will help, until you get your hand in, is to try and keep the weld in the flat position, on tubing roll it as you weld it. The angle of your mig gun will make a big diffence in how the weld piles up, if you keep the angle pointed up the weld joint the arc force(not much with a mig) will help lay the iron down. On light stuff like this you want to set up so that your travel speed can be kept pretty fast. There is nothing wrong with making two fast passes intead of trying to pile on one cold one. As far as food safe, I dont pretend to know everything but I dont know of a common stainless that wouldn't be.
Hope I helped.
Kyle
 
One other thing. What if the stainless you use is not 316? What metal in the stainless alloy would you need to be concerned with? I am continually amazed at the vast amount of knowledge in this forum. What an eclectic group. - Dwain
 
You need to be sure of the alloy you are welding with/ joining too. Generally a beer keg itself is fine since it's alloy is already food grade
( make sure it's Stainless steel, not aluminum). 300 series stainless is in most cases fine for food. 304. 316, 303.... 303 Stainless would be the last choice as it corrodes more readily from cleaners and probably won't weld as clean.
 
I think you could get away just fine with 316 on a keg or kettle. A lot of the kettles I see advertised tell you what alloy they are. Another tip for stainless is that it needs to be very clean. We buff all of our pipe joints with a tiger paw so they look like a mirror, and dont use a steel wire brush-stainless on stainless. Once you get your hand in it I think you will like it, it makes a very pretty weld, its just a little more prep work than carbon.
 
wow, you go away for a day and i come home with all this homework about my stainless welding. i dont even know where to start.


thanks for all the info.

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.
 
As stated before don't use anything with carbon steel to prep. If you use cutting wheels make sure they are new or have never been used on carbon steel. I think aluminum oxides are ok but not 100% on that. any carbon steel that touches it will (rub off) and you will have a rust point.
 
ok, i should be able to come up with something. are there any chemicals or types of flux i should be using or not using? of is flux not necessary because i am using the shielding gas?
 
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.
 
Wow this is all great info! I am looking to weld some keggels soon but only have acess to a gas set up. Anyone recomend a good flux or even a brazing rod for 316?
 
Just for practice and to see what the back of you weld will look like with out back gassing weld two pieces together and look at the oxidation on the back side it's not pretty...Think about that being in your fermenter.

Your puddle timing looks good but you wire speed is to high and you heat is to low...Also it's much harder to get a leak proof seal with a mig as compared to a tig.

Pat
 
so i was doing some more stainless practice today.

i was almost done my 3 tier rig and i fired up the burners. stupid me i didnt realize that the top burner was way to close to the hlt.

so instead of moving the burner or cutting apart the rig i decided to weld feet onto the hlt. i had some stainless here so i figured i would give it a shot.

i put 3 "legs" on.
May09_0004.jpg


as you can see i am not good at this

but after messing with temp and wire speed i came away with this
May09_0005.jpg
 
Looks like the weld current is too low, the weld should be concave not convex like shown. Practice on some carbon steel scap first, puddle should stay flat not hump up like that, start at 80 amps and go up from there. The faster the weld is made the lower the heating of the adjacent metal and the lower the shrinkage and warpage after.
 
the problem with that is i have a lincoln 125. the amp settings are not numbers, they are A..B..C..D..E..F..G.H..I ...J. i think. and the wire speeds are 1-8? i think. i have noticed that most of my welds with this machine are convex and not concave. whenever i up the heat, i burn through. does that mean i am moving too slow?
 
You need to up the Amps, wire feed and travel speed together, you should be laying a bead at about 1/4-3/4" a second for 1/8" material. If you have burn through up the wire speed and travel, stitch weld thin stuff (1" weld - 1" gap - 1" weld) grinding the tail end of the weld to taper the thickness to 1/2 weld bead thickness makes for a smoother tie in when you restart (no humps).
 
ok, i was on the low end of that speed. possibly 1/8 to 1/4" per second. the faster i moved, the nicer the welds looked. its very different from stick welding.
 
I have done Stick, TIG, and some wire welding on stainless pipe, tube, and shapes, faster was always better. You would be suprised at the amperage used with the various methods, ~40-50 for .049 - .065 wall tube, 90 -110 for SCH 10, 100 - 125 for SCH 40 pipe. If you dont have a backup flux yet get some "Solar Flux" or "Superior #9", if applied thick enough it can delay burn through on light material and prevent "Sugaring" on the backside of welds.
 
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.
 
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!
 
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]
 
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
 
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!
 
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.
 
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
 
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