Mig welding sheet stainless

[Bluemotion]

I don’t usually ask daft questions but in this case I want to forward plan a job. I’ve a stainless bespoke shower tray to make for a ‘Track day’ motorhome come work shop. There’s a chance I’ll be doing metre long seam welds which will be for substitute folds as it’s complicated. I’ll probably use 430 brushed stainless @‘hopefully’ 16 gauge. I’ll run .8 wire but the question is will CO2 gas be compatible? I’ve some argoshield I could probably cobble up somehow as I’ve a decent tig but not enough experience with it to produce stunning work yet.
The welds will be polished in as I don’t want joins on show.

As a back up would gas less wire actually produce a fair weld or do you steer clear. As a rule I’ve never seen an impressive weld that’s ever been pretty with gasless but that’s on mild steel.

 

[Brad93]

No you need argon with a tiny bit of CO2.

97/2.5 or 98/2

 

[Brad93]

430 is ferritic or utility stainless. No good for that application.

 

[Brad93]

TIG needs pure argon not argoshield.

 

[Brad93]

Gas less stainless wire not suitable for the thickness and finish you require.

 

[Brad93]

Have you thought about distortion. This is one of those jobs you’d be better farming out. @Paul. or @Hitch are the resident stainless experts.

 

[Bluemotion]

No you need argon with a tiny bit of CO2.

97/2.5 or 98/2

Actually thinking about it I have pure argon not argoshield. As for 430 grade I had a quick google look earlier as it’s used for cheaper end sinks so thought it might do but if you think it’s total garbage then I’ll up it. This thing I’m making is more ‘service van’ than motorhome therefore ‘good enough’ is where I need to be with it. I’m not too worried about heat movement as it’s on strong 90” folds and will be pulse welded gently. Thanks for your knowledge Brad

 

[Brad93]

Actually thinking about it I have pure argon not argoshield. As for 430 grade I had a quick google look earlier as it’s used for cheaper end sinks so thought it might do but if you think it’s total garbage then I’ll up it. This thing I’m making is more ‘service van’ than motorhome therefore ‘good enough’ is where I need to be with it. I’m not too worried about heat movement as it’s on strong 90” folds and will be pulse welded gently. Thanks for your knowledge Brad

you’d probably get away with it. Ferritic grade less tolerant to scratching and embedded metal particles to start rusting. Like grindings you’ve washed off etc.

 

[Bluemotion]

Its a bit of a weird one as this base will be in the workshop floor not the resident side of the vehicle and quite large similar to a 'wet' room therefore there will be race bikes rolled over it when packing away. 430 grade like you said might definately need upping.

 

[TechnicAl]

If its cheap stainless you want Id go for 3Cr12........easier to weld and form than 430

https://www.aalco.co.uk/datasheets/Stainless-Steel-14003-3CR12-Sheet-and-Plate_96.ashx

 

[Bluemotion]

If its cheap stainless you want Id go for 3Cr12........easier to weld and form than 430

https://www.aalco.co.uk/datasheets/Stainless-Steel-14003-3CR12-Sheet-and-Plate_96.ashx

Just as I'm learning simple understandable stainless code numbers you throw a curved ball! Bloody heck

 

[TechnicAl]

Just as I'm learning simple understandable stainless code numbers you throw a curved ball! Bloody heck

Its just the simplest form of stainless.....low carbon with 12%Cr

to be honest I think 304L would be the best choice but its more expensive (its 18Cr 8Ni...the Cr makes it stainless and the Ni makes it ductile)

 

[Hitch]

I'd try and fold as much as possible... suprising what a good press operator can do... got a picture of the shape?

Try and minimise any welding.... are you planning on welding the inside corners of the tray then polishing the welds out?

A nice little autogeous tig just to seal it up would be my choice.... if I had to.

304 would most likely me more readily available, no idea on the cost differences though tbh, never bothered with the ferretic stainless grades.

 

[Paul.]

As Hitch says 304 is the material for this job, I would buy 2B sheet which is just a grey mill finish, then finish it with a dual action sander with a 60 grit disc then green scotchbrite also on the DA, that will give you a random sanded finish that is easily repaired when it gets marked, made loads of bootwash trays like this,
Mig is not the tool for this kind of work, bend as much as is possible and use TIG to weld any joints, you will find a copper backing bar is useful to keep the heat from distorting the tray and stop you blowing through.

 

[Bluemotion]

As Hitch says 304 is the material for this job, I would buy 2B sheet which is just a grey mill finish, then finish it with a dual action sander with a 60 grit disc then green scotchbrite also on the DA, that will give you a random sanded finish that is easily repaired when it gets marked, made loads of bootwash trays like this,
Mig is not the tool for this kind of work, bend as much as is possible and use TIG to weld any joints, you will find a copper backing bar is useful to keep the heat from distorting the tray and stop you blowing through.

What would you call a copper backing bar? I can see how it would work but only things I have in copper are 15/22mm pipe.

 

[Bluemotion]

I'd try and fold as much as possible... suprising what a good press operator can do... got a picture of the shape?

Try and minimise any welding.... are you planning on welding the inside corners of the tray then polishing the welds out?

A nice little autogeous tig just to seal it up would be my choice.... if I had to.

304 would most likely me more readily available, no idea on the cost differences though tbh, never bothered with the ferretic stainless grades.

I was thinking of doing it in one lump with all the folds (as there really is enough to fold) and then gently run the corners in then polish flat or as near dam it since they’re concave but that’s a lot of complicated folds in one shot so I might make it in three sections, section 1 will be the main dish and 2 and 3 will be L shaped. I generally fold things myself by hand and I put a hidden groove on the underside as a folding line since it helps it along nicely.

 

[hotponyshoes]

What would you call a copper backing bar? I can see how it would work but only things I have in copper are 15/22mm pipe.

A length of that would do the job if you can hammer it flat enough to make contact.

 

[tom2207]

A length of that would do the job if you can hammer it flat enough to make contact.

old buss bar if you know a spark that does bigger stuff ,, often the local scrap yard will sell you some for a bit over scrap prices , it will never go to waste.