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Welding thick 304 SS

robbor

Aluminum
Joined
Feb 18, 2008
Location
Los Angeles Ca
I need some help. I lucked into a big batch of 4x6x3/8 rectangular tube. Id like to turn them into building support posts. So id need to attach base plates to all 11 pieces. Never welded b4.
What kind of welder do i need to weld this thick (3/8)well? Tig im guessing would be best?
Most of the welding ss i see online is thin stuff, not structural.
 
Stick welding stainless is easy. Mig would be second choice. Bolt on angles 3rd. Braze 4th. Wire feed tig 5th or first — but those are very specialized welders.

tig would be last in list. Very last.
 
You will find the consumables costly ......such as a 5kg packet of rods over $100........You might also find for pillars /supports you dont need very large beads ...certainly not 100%,maybe 25% ,provided your fitup is good .
 
Hmmm. I have fabbed literally tons of stainless over the years. my work is all required to be top visual quality- furniture, architectural detailing, fences, rails and doors for high end buildings, and sculptures. We never stick weld anything except structural stuff over 1”, which usually doesnt show. We mig very little, as weld bead cleanup is excessive, again, this is mainly for cosmetic reasons, mig is fine from a structural perspective but its butt ugly, and I,and the various welders who have worked for me over the years are all quite proficient.
we tig everything, always, if at all possible. Most welds get sanded completely invisible and then electropolished, but if a joint shows as welded, I find tig beads universally better looking than mig.
one of my ex employees is a specialist in autogeneous tig for brewey and distillery work. That means absolute perfect penetration flat beads with no filler rod. Obvio, no mig allowed.
Stick is clearly the cheapest to tool up for, cheapest machines, and just fine from a structural viewpoint.
If you dont really care about appearance (and this is true to me even if you are really good at stick), its fine.
wont fly with any of the clients I have worked with, but it will stick that tube together.
a decent stainless mig setup can easily be in the same price range as tig, and for me, the flexibility of tig, and the ability to weld mild, stainless, copper alloys and bronzes, and aluminum, makes it a no brainer. But I dont build industrial shelving or machinery frames.
everything we do has to be purty.
 
Hmmm. I have fabbed literally tons of stainless over the years. my work is all required to be top visual quality- furniture, architectural detailing, fences, rails and doors for high end buildings, and sculptures. We never stick weld anything except structural stuff over 1”, which usually doesnt show. We mig very little, as weld bead cleanup is excessive, again, this is mainly for cosmetic reasons, mig is fine from a structural perspective but its butt ugly, and I,and the various welders who have worked for me over the years are all quite proficient.
we tig everything, always, if at all possible. Most welds get sanded completely invisible and then electropolished, but if a joint shows as welded, I find tig beads universally better looking than mig.
one of my ex employees is a specialist in autogeneous tig for brewey and distillery work. That means absolute perfect penetration flat beads with no filler rod. Obvio, no mig allowed.
Stick is clearly the cheapest to tool up for, cheapest machines, and just fine from a structural viewpoint.
If you dont really care about appearance (and this is true to me even if you are really good at stick), its fine.
wont fly with any of the clients I have worked with, but it will stick that tube together.
a decent stainless mig setup can easily be in the same price range as tig, and for me, the flexibility of tig, and the ability to weld mild, stainless, copper alloys and bronzes, and aluminum, makes it a no brainer. But I dont build industrial shelving or machinery frames.
everything we do has to be purty.
whaaaaaaaaaa? you must have been doing something VERY wrong. mig welding stainless when done properly looks fantastic!

1697629593350.png

what about this is butt ugly?
 
Stick by far the cheapest. A lincoln AC buzzbox will do very well for this work.

If you've never welded before it will take a bit to get the hang of it. Main thing, if you can't see and undedstand the puddle you will not do a good job at all.
 
Keep in mind this is b4 stainless, which is a very specialized grade of steel. The OP has (presumably) welded a lot of other types of stainless steel, just not b4.
 
Keep in mind this is b4 stainless, which is a very specialized grade of steel. The OP has (presumably) welded a lot of other types of stainless steel, just not b4.
Don't think you are reading the OP correctly. I think b4 means before, not 304b. Especially with the questions about what kind of welder is apropos.
 
whaaaaaaaaaa? you must have been doing something VERY wrong. mig welding stainless when done properly looks fantastic!

View attachment 412538

what about this is butt ugly?
We would have to grind/sand out all the grooves between the welds. This is structurally great, I am sure it doesnt leak.
But no, by my standards, its ugly, and compared to a tig, it would require and extra hour of work to be acceptable.
There is a certain macho flair to big weld beads. But architects, building owners, and people who commission expensive stuff in stainless generally dont appreciate it.
Plus, this is obviously indoors, and so you dont have to worry about rust spots developing- we generally have to have our exterior stuff electropolished, and it works best on nice smooth rounded transistions.
You should see my buddies brewery vessel welds- you cant even tell it was welded. He was trained by these scottish guys from a giant brewery vessel maker in Canada, and they were VERY picky.
Every weld was internally checked with video cams inside the pipes, even in 3/4" schedule 10 pipe, and zero defects are allowed. And, as I mentioned, autogenous. No weld bead, inside, or out, and no weld depression either.
 
We would have to grind/sand out all the grooves between the welds. This is structurally great, I am sure it doesnt leak.
But no, by my standards, its ugly, and compared to a tig, it would require and extra hour of work to be acceptable.
There is a certain macho flair to big weld beads. But architects, building owners, and people who commission expensive stuff in stainless generally dont appreciate it.
Plus, this is obviously indoors, and so you dont have to worry about rust spots developing- we generally have to have our exterior stuff electropolished, and it works best on nice smooth rounded transistions.
You should see my buddies brewery vessel welds- you cant even tell it was welded. He was trained by these scottish guys from a giant brewery vessel maker in Canada, and they were VERY picky.
Every weld was internally checked with video cams inside the pipes, even in 3/4" schedule 10 pipe, and zero defects are allowed. And, as I mentioned, autogenous. No weld bead, inside, or out, and no weld depression either.
while i dont disagree with you that TIG welds look much nicer, we're talking about different things here, structural vs food processing. the pic i posted, those quality MIG welds would be more than acceptable/desired in the structural industry.
 
I need some help. I lucked into a big batch of 4x6x3/8 rectangular tube. Id like to turn them into building support posts. So id need to attach base plates to all 11 pieces. Never welded b4.
What kind of welder do i need to weld this thick (3/8)well? Tig im guessing would be best?
Most of the welding ss i see online is thin stuff, not structural.
Have you tried to sell the SS tube? Buy mild steel posts and take a vacation with the remainder.
If you’re buying your first welder only for this purpose, like said just get them tacked by a contractor. A couple tacks is all it takes.
 
You will find the consumables costly ......such as a 5kg packet of rods over $100........You might also find for pillars /supports you dont need very large beads ...certainly not 100%,maybe 25% ,provided your fitup is good .


on the mig side, not only will the cost of the wire gag you, the cost of a bottle of tri-mix gas will send you over the top.
 
Must the welds be stainless? If not, glue gun it together with a MIG and good ole ER70S-6 wire and be done with it. Sounds barbarian but if the sole goal is to stick the parts firmly together that is all you need.
 








 
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