I need to cut the collectors off some SLP headers, which I think are 409 stainless, and I'll be using some 16 gauge 409 stainless j bends to make it up.

I'm planning on using 1/16 stainless filler with my Miller TIG. Does that sound about right?

Alternatively, I could buy a spool of wire for my mig, but the TIG has been collecting dust and it's probably the better welder for this application, no?

-- Joe

 

That sounds about right to me... i would not go spool gun on headers anyways... personally i have never liked stanless MIG... just a bit to sloppy for me. If you have a stick welder you could buy some 3/32 stainless rod's and use that to. So if it was me i would go with the tig application and make it look nice. just be careful not to get it hot.

 

Sounds good.

My TIG was purchased for alum, and as such my tank is currently full with 100% argon. Will I get away with that? I'd hate to have to dump it and refill with a mix for one project.

-- Joe

 

Argon works fine for stainless tig. For mig you really need trimix.

 

Awesome. I don't mind buying a pound of rods, but I didn't want to spend $100 on materials for one weld

Thanks

-- Joe

 

Tri-mix works soooo much better for stainless mig. 100% argon is fine for TIG

You can also use a mix of 98% Ar and 2% Co2 for MIG any more than 2% Co2 produces to much carbon and reduces the quality of the stainless bead.

I prefer TIG when it comes to stainless, stainless welds have the prettiest look and its much easier to be consistent with the TIG.

 

I dont ever recall useing a mix for stainless tig welding so 100% argon is just fine. just make sure your using the correct tungsten for a stainless application, Gold end i think, and set the machine accordingly. (not sure if you knnew that or not so i just though some extra information in there, best of luck!)

 

I have always used 100% argon for stainless.
I tried to search and find results of what happens when mixed gas is used on stainless but I couldnt find anything and I didn't want to find out the hard way.

 

Straight argon for welding stainless tig. Adding oxidizing like CO2 or O2 contaminates the weld.

For stainless mig you do NOT! need trimix but you do need about 97.5/2.5 ar/co2. Straight argon will not wet the puddle and you will have a very very ahrd time getting stuff welded together. You need a little CO2 for wetting. You can use regular 75/25 gas for welding mild steel, it will weld just fine but it will oxidize the weld, leaving it black. Being 49 that scales over I wouldn't spend a lot of $$$ on expensive bottles of gas to weld it.

 

Yeah, I have no idea on the settings. I think I'll download the manual for this machine to get the baseline. This is an older tig, but it does have the high freq start. It's not great but it works.

I didn't think of the tungsten, and I forget which diameter I have in the torch right now. I'll have to review that when I get home and pick up the right consumables.

It's a miller econo twin HF. Here is a picture of the same model.

(and manual) http://www.millerwelds.com/om/o302j_mil.pdf
-- Joe

 

Straight argon is just fine for stainless.

I've had very good results from mig with C25, much better than using the straight argon in the mig.

1/16 will work, .045 may work a bit better, i've used both .035 and 1/16" for similar thickness tubing, both can work fine.

1/16" tungsten.

 

You can not mig weld with stainless wire and straight argon, you will get a bead that does not flow well into the parent metal. C25 will work but your weld will oxidize, turn blackish gray.

 

If your welding 16 gauge stainless i would probaly start at 60 on the HF dial and around... 20-25 CFH on the gas flow... 12-20 on amperage.. i would def get a test piece or two for fine tuneing the settings before i welded my 600$ headers. On the tungsten i would go no bigger than 3/32. for 16 guage i would use 1/16 tungsten (with the gold color stripe)

 

Thank you for the advice! Will report back.

I will cut up some scrap 409 and make some test welds before I actually ruin err weld my SLP headers.

-- Joe

 

i think you could get a way with 3/32 2% thoriated(red end) you may want to run a Y off your flow meter and purge the back side of the weld or else it will sugar on you

 

Yes you could get away with 3/32 2% thoriated tungsten, but if you choose to do so be very, very cautious, and move fast. it really depends on your welding style, burn it hot and fast, or a little cooler/slower, or however else you want to weld. If you dont have a 400$ tungsten sharpener i would recomend useing a new grinding wheel to grind the tungsten just to ensure no oil/other contaminets enter your tungsten, its a hassel to go and buy a new grinding wheel for sharpening tungsten your just going to use once, but you could probaly get away with useing what ever's handy i just like being extra careful when i weld with tig because its very easy to contaminate a tig weld.

 

Definetly a suggestion to not ignore, even aside from the sugaring, backpurging is a great thing.

 

That sounds like whats been happening to me. I have been using a lot of heat to get the weld to spread.
What about a argon helium mix?

 

I was told that you had to use a putty or compleatly surround the weld with gas or the welds would be brittle?

 

Welding anything stainless is just a pain in the a$$. i weld for a living but try to stay away from stainelss if i can. And yes it will become brittle unless you properly shield it from atmospheric contaimnation and other sources of contaimnation.

 

I think you mean something like solarflux, it can be used instead of backpurging, its brushed on inside the joint near it, when the welding starts the heat cooks it and makes it give off the shielding gas needed.


I havent seen any brittle issues with non backpurged stainless, and plenty of others have done it as well. However great prep combined with backpurging generally results in a much better weld.

 

to avoid having to backpurge they do have stainless filler rod with a flux core but not sure where you can find it, we use it in powerplants on boiler tubes but maybe gendco or other welding suppliers would have it, other than that clean it up with a flapper wheel and take your time, you may have to weld some and stop to keep the heat dowm, also keep a spray bottle of water near by and cool it down often, you dont have to worry about it quenching it making it brittle like carbon steel

 

Hadnt heard of the stuff and just had to do some looking, apparently it leaves behind slag often that needs to be removed, sounds like a bad idea for something that you want smooth flowing.

 

What he said, for TIG straight argon and preferably some 309L filler. Something in the .040" range will work well.

For MIG you want gas that will help wetting... straight Ar will just cause the weld to pile up. C25 that you normally use for mild steel will work fine- I'd bet that not many will be able to tell you used it. You need some of the more "exotic" gasses if you're doing food grade welds in stuff like 304 or 316. Production line 409 is done with a specific flux core wire _and_ shielding gas, but 309L (low carbon) and C25 will do a very nice job on it (308L seems more common and will work in a pinch). Honestly, if you're not worried about some rust on the surface of the weld bead even ER70Sx (mild steel filler) will work well on 409.

You shouldn't have to back purge 409, but it wouldn't hurt. DO NOT quench it unless you're using a specific filler designed for that, almost every other filler will harden and or even crack if you do that.

I have a MIG and TIG, and unless I really, _REALLY_ cared how the welds looked (I don't see a point in 409, it will get a coating of oxides anyway, unless you coat it, and then again, it will not matter), I'd just MIG it with whatever I had sitting around. Even ER70S6 will be fine, it will rust but that will come close to matching the rest and the weld will be the heaviest point so it will not rust through there.

 

I have a bottle of CO2 and a bottle of argon I don't want to add a 3rd bottle of C25.
Are there any gas blending regulators out there made to blend gasses or do I just have to tee them together and wing it?

 

I found blend regulators for He/Ar, all I would need to do is switch out the flow regulator glass or hand mark one of the flow glasses for CO2.
I would like to have CO2, Ar and He on tap at all times.
Now the only problem seems to be there is a helium shortage.