SS 308 or 309 TIG filler rod

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Going through past threads regarding filler rod for tough applications, such as unknown steels, steel to cast, building up a broken bolt to be extracted etc, I have seen recommendations for SS308 0r 309.  Kind of like if you were using super missile weld if you were stick welding. At my local welding store, 308 is readily available, while 309 is not. Should I order it, or is it going to be about the same thing?  My main applications would be bolt build up, to extract with a nut on top. Unknown steel types I don't want to fail, for example tigging a chromed rod on a hydraulic cylinder.  So is 308 interchangeable with 309?
Reply:I'd say 309 is more versatile.
Reply:309 is a carbon to stainless rod 308 is stainless only
Reply:SS309 is a better choice for welding mild steel to stainless or unknown to unknown.  the 309 has more Chromium and Nickel, which helps avoid problems with cracking.  Using 308 on mild steel can result in weld bead cracking if the dilution with the base metal is not right.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:If I can remember to look, or maybe you can search it, there are charts floating around the web for filler metal selection.
Reply:309L is what you want. Commonly available, maybe find a better LWS or use weldingsupply.com.JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:Originally Posted by blackbartGoing through past threads regarding filler rod for tough applications, such as unknown steels, steel to cast, building up a broken bolt to be extracted etc, I have seen recommendations for SS308 0r 309.  Kind of like if you were using super missile weld if you were stick welding. At my local welding store, 308 is readily available, while 309 is not. Should I order it, or is it going to be about the same thing?  My main applications would be bolt build up, to extract with a nut on top. Unknown steel types I don't want to fail, for example tigging a chromed rod on a hydraulic cylinder.  So is 308 interchangeable with 309?
Reply:I was using super missile weld as an example of a "do anything " rod for welds that can't fail. I didn't know they made it in a TIG filler as well. I have always been told it's probably not any more than 309. I may be wrong.
Reply:"Super missile weld" and such things are 312, which has higher strength than 309 at the cost of less corrosion resistance. 312 TIG wire can be found but is not as common as 309.JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:308 has more uses. be sure to buy 308LMo though.309 is for stainless to carbon steel and buttering stainless.312 has better mechanical properties.It depends. On both what you need the weld to do, as on what you are welding and what you're welding it to.
Reply:Originally Posted by kingnero308 has more uses. be sure to buy 308LMo though.309 is for stainless to carbon steel and buttering stainless.312 has better mechanical properties.It depends. On both what you need the weld to do, as on what you are welding and what you're welding it to.
Reply:Originally Posted by kingnero308 has more uses. be sure to buy 308LMo though.309 is for stainless to carbon steel and buttering stainless.312 has better mechanical properties.It depends. On both what you need the weld to do, as on what you are welding and what you're welding it to.
Reply:308LMo is low-carbon with added molybdenum. Similar applications as 316L.I use 308LHS and 309LHS with MIG but never used it for TIG. The added silicon helps weld puddle fluidity and wetting of the weld edges.JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:Originally Posted by shovelonSo I learned something here. SuperMissileWeld is 312 alloy. Good choice for molds and dies, and good all around repair filler.
Reply:so if you had to have just one type would most prefer 309, (most versatile?) will it do as good as 308 in stainless to stainless
Reply:I didn't realize there was such a difference, I never heard of 312.  I ordered some on ebay (I couldn't find it anywhere else).  I am going to experiment for a while! Thanks for the input.
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