Hello everyone, I am a pretty good (intermediate) welder using my MIG (Millermatic 175). 100% of my work has been mild steel, the stuff you find at the metal yards. Now, I am facing a new welding job for my 1939 LaSalle Coupe. I still have the original flathead 322cui engine and I will be replacing the rotted-out water outlets that come off each side of the head. I am going to make the flange and order the pre-bent 90º pipe both made out of Type 304 Stainless Steel. All I need to do is a simple fillet weld around the pipe onto the flange. My question is, Can I use the same gas (75/25 Argon/forgot the gas) and SS wire using my Millermatic 175? I read about a Tri-Mix gas, containing helium in the mix but I have also read about others getting away with their 75/25 mix of gas and using 308/308L Stainless steel solid wires. Please provide any feedback if you have ever welded Stainless Steel? Any tips? Tricks? Anything I should look out for? Here is a sample image of the engine I am working on - note the front water outlets protruding out of the engine:
Well, I've never tried to MIG SS. But I've TIG welded it a million times with both 100% Argon and 100% Helium. It welds a lot like regular steel, but you have to be careful not to get it too hot. If you do, you will burn the chromium out of it. If you get a whiteish yellowish powder around your weld, this is what is happening. So unlike mild steel, you can't just cook the shit out of it and expect to not have repercussions. I'm not sure if the C02 mix would be a problem or not.
Yes, if all your going to weld is the water outlets, its probably not worth getting another bottle of gas as the 75/25 welds can be cleaned up. If you are going to mig weld a lot of s/s, tri-mix is the way to go as it welds much smoother and the weld appearance is much better. Splatter is still a problem, and I recommend the Walters/Waters (?) brand anti-spatter spray, works great.
I use straight argon when mig welding stainless. Try your co2/argon mix on scrap first since you have it.
Junkyard, your quite right, I had my head up my ass, I've never tried it with 75/25 just straight argon or, better yet, tri-mix. My bad.
the tri-mix is used for food grade where the welds need to be smooth without imperfections for easy cleaning,bacteria is pretty small. your 75/25 should work fine. i would call your local welding supplier and ask.
You could also braze it with silver brazing alloy. But you'll need a special black flux that contains fluoride salts, and then you have to be careful not to breath the toxic fumes from the black flux. They sell a certain alloy of silver braze that's almost the same color as stainless steel and it makes a nice looking small fillet that's easy to polish up.
wow, never heard of such a thing...when brazing, we're talking about lower temps, right? compared to MIG welding... I also have an Oxy/Acet rig...
I just got done welding up a stainless exhaust system for my 40. I talked to the welding shop and they said that the argon/ CO2 would be fine. I picked up some SS wire and tried on some scrap. Lots of spatter. I purchased some anti-spatter spray and proceeded with the job. It worked great. I did turn the tension down on my feed wheels as the SS wire is a bit softer and wanted to bunch up at the feed mechanism if there was any hang up at the tip.
Yeah, it's done at a little lower temps than usual brazing. Some people call it silver solder, but technically, it's a silver braze alloy. Check the websites of Harris or other companies that sell a long line of silver brazing alloys. The alloys with more silver look more like stainless, and they flow really nice and make a really nice small fillet. The black flux is pretty nasty though because it gives off acid fumes. You need the special black flux to eat off the chromium oxide on the surface of the stainless (which is what makes stainless steel "stainless"). The silver braze will only stick to areas that are wet with flux (it'll just bead up and roll off where there isn't any flux). It's kind of tricky the first few times you try it, but it looks nice when you get the hang of it. Silver braze is pretty strong too. If you look at something like a stainless steel hot dog cart, big pots and pans, or coffee pots, you can probably find some places where they silver brazed some seams. It'll look slightly brighter at the braze than the rest, and sometimes a slightly different color (sort of a bright nickel color). Good welding shops will usually sell the black flux and the silver braze alloy wire if you want to try it sometime. Make sure the flux says it's for stainless steel. The white flux won't work usually on stainless. Silver braze wire is a little expensive due to the silver content, but you usually don't need much of it if you have snug seams. For something like your flanges, you'd probably use 1/16" diameter wire. You might experiment on some junk parts first because it takes some getting used to. The hardest part is learning what temperature to get the metal to before the silver braze will start to flow into the joints.
Rusty, I picked up some stainless stantions and was thinking of which welding method for chopping 2" out. You have a good alternative here! Thanks.
I have heard that stainless can be welded with a cobra welder ( the new name for Dillon ). Have any of you fellas ever used a Cobra for welding stainless?
O.K., I wasn't going to mention it. I thought you were going the mig route, (fine by me). However, if you want to use a gas torch, don't mess with brazing, just gas weld it. All you need is some stainless filler rod. Scraps cut into strips will work or you can buy cheap SS filler rod. All you have to do to gas weld it is to adjust your standard welding flame but leave a feather on it about 1 1/2" long. You will be amazed how well stainless flows, (like butter). The feather is a natural shield. The Cobra, (Dillon), (Henrob), whatever is O.K. but pricey, I have one but seldom use it. You can weld with a regular Oxy-Acetylene welding torch.
I live in Yorba Linda Ca, ( Orange County) and would be more than happy to tig them up for you. i also run a mandrel tube bending company www.tubesolutions.com and may have some (304ss 90's) depending on the size. let me know Adam
I'm convinced that using a good TIG is cheating; and I'm okay with that! TIG on stainless might be the easiest-cleanest welding combination ever.
I wouldnt waste your time with a mig welder. The welds will need cleaned up and it will take some time making them look really good. Plus its always tougher to get a water tight weld with a MIG welder. Not sure how perfect you want them but I would suggest having someone TIG weld them. If you plan on welding the 90 to a flange make sure its backpurged. If not you have a "sugar'd" looking weld on the inside of the weld. This will create a weak joint. If its a small amount of welding, pay someone or ship it to MO and I can weld it up free other than the shipping. I weld sanitatry .065 tubing in a food manufacturing plant. All we do is stainless tubing and thin sheet metal. The inside of the weld will look like the outside of the weld if done correctly. Jeff
You can weld stainless with you MiG .But you need to use Argon gas .Also use a .25 stainless wire in the MiG and turn the welder up a little more than normal .Back when I was first starting out I used this method all the time .It will be a little messy but it will work .My 2 cents
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