Stainless project

[youngwelder_154]

Hey guys, I'm starting my second project on stainless my first one was a pretty good success but I used 20g sheet metal and I don't have the ability to weld that yet one of the guys at DME had to go over it again in pulse to fix the damage I caused. Now I'm stating a stainless tool box which I will be doing myself with no help (other then the person who bent the sides I'm not allowed to use the press yet.) He also helped me with picking out the size etc. I'm going to be done of it hopefully early next week and at that point ill post pictures of both results. But could you explain to me how I can weld the 12g to 16g I realized id have to put most of the heat on the 12g (for the sides of the box) when I weld the joint I want to make sure I don't burn through it or warp it. I'm going to be trying welding a little and cooling it down with compressed air, I'm hoping that will solve my problem. any advice will be greatly appreciated I don't get to work on it again until monday which I'm really bummed on so I have the weekend to plan what I will be going through with doing. so thanks in advanced for the advice I will hopefully be getting.

[phaxtris]

if you want to minimize warping dont rely on compressed air, you will want to clamp it in every way possible

as for the actuall welding, its not so bad, im shure you will figure it out

[Anti-GMAW]

Compressed air will make oxidation occur more rapidly. It won't look as good and will lose some of it's ability to combat corossion.

[chris madden]

weld a little at a time and weld all the sides evenly so do a little on one side and a little on the other .

[fun4now]

i would do lots of small stich welds moveing around to alow it to cool of inbetween welds. spread the heat out and move it around.
good luck.
you will be back purging it right???

[youngwelder_154]

Thanks everyone for your advice everyone I'm thinking doing little stitches and ill post the pictures as soon as its done. Thanks guys again!

[brightspark]

Not sure on the design of your box but if you're tryin to weld open corners then maybe you could use a copper or aluminium backing bar. This can be used as a jig to keep the corner square whilst welding and will stop you burning through. Another advantage is it would act as a heat-sink which would reduce the amount of distortion.

Just my thoughts - make of them what you will.

Brightspark

[youngwelder_154]

That's what I herd I should use to reduce burn through, it will actually keep my pieces from warping as well?

[HMW]

Fun4now

Backpurging? is that where you use a gas like Argon on the back of the weld while your welding it?? Have welded a few things out of stainless with TIG and a couple with SMAW, worked OK but didn't back purge either?? can you explain?? I have heard of it just not sure about it...Thanks

[fun4now]

yes its keepingthe back of the weld coverd in shielding gas, they also make a past you can put on the back. with thiner SS it will get all black and lose its rust preventative qualitys as well as look realy bad. not so bad on thicker stuff as the back dose not get the full heat but on thiner stuff its a prity big deal. it almost looks like you welded it with no gas.

[Samurai Dave]

Back purging stainless

Backpurging? is that where you use a gas like Argon on the back of the weld while your welding it?? Have welded a few things out of stainless with TIG and a couple with SMAW, worked OK but didn't back purge either?? can you explain?? I have heard of it just not sure about it...Thanks

You are correct. Purging consists of replacing the air on the backside of a weld with argon. This can be as simple as taping cardboard to the back of the metal to form a channel to seal the area for argon. The main reason I have a flow meter with two seperate outlets is to purge with one (@ higher psi), while welding with the other.

Welds in stainless can be done successfully without purging, but the back side (of a butt weld) will have "cauliflower" growing out the backside. This is how the stainless steel reacts with the atmosphere, which is not pretty. It can be ground-down, but takes work. If you are welding a box, that inside corner where 3 side come together is expecially hard to fix with a grinder. Most of the time when the customer is paying a premium for stainless, they expect the welds to be not only strong, but cosmetically appealing as well.

[JonnyTIG]

Back purging stops the vegetable effect? Kudos on the mental imagery 'Sugaring' is the term I've learned, but not as descriptive as cauliflower.

If the stainless is 1/8" or thinner, and not requiring multiple passes, you can use a product called Solar Flux, type B. Paste it onto the back of the joint, and it will shield the root reinforcement the same as back purging, but only for a single pass. It is used for thin wall pipe or tubing, yet is versitle engough to use for cabinets and plate projects.

[Anti-GMAW]

Sugaring is carbide precipitation. It's accelarated when an inferior atmosphere is present (unpurged open roots, etc.). In certan stainless aplications nitrogen and/or nitrogen mixes are acceptible (particularly with GMAW).

[HMW]

I thought thats what I had read. Thanks for the explanantion. Now that I think about it what I have welded that was stainless was a barbecue grille grate, hammock stand made out of stainless square tubing and repaired some restaurant equipment. So I guess nothing thin and you couldn't see the back side. It would seem that back purging would be expensive, but have no choice i guess.

[youngwelder_154]

I was thinking hard about purging it but since it will be an open ends theres no way I can do it with out the help of another person. I have no one at the shop to help me so I'm thinking I'm just going to fuse the ends together since its just 16g I might need a little filler but other then that I think ill be good to go. Today I'm ready to start the welding of my project so wish me luck