Hi Guys ! I have welded regular steel before but never stainless. Is it possible to weld thin ss tubing like about 14 gauge material.Then grind it down and polish it out so its almost invisible ? Also bending the ss tubing without it kinking ? Why do I want to do this. I was wanting to make some three and one half inch. exhaust pipe. I need to pipes with 90 degree bends in each. So I got to bend the pipe somehow to 90 degrees. Or I thought about getting two factory bent 90 degree elbows the same size and welding then to my pipe and hand finishing them. Maybe using something like 304 ss tubeing. Any body ever done this ? If so how. Thanks !!!!

 

[updated:LAST EDITED ON 04-Dec-02 AT 09:15 PM (EST)]TryMe,

You betcha it can be welded. Use a MIG and if your looking to polish without future discoloration I'd suggest using stainless wire. You can use mild steel wire too but might show some light rust eventually. Using mild steel wire doesn't seem to oxidize much tho as it seems the weld pool must be able to pick up enough nickle from the stainless in the welding process. As it looks like your looking for the best appearance tho the stainless wire is your best bet. Weld and grind down then polish with a sanding disc using finer and finer grits 'till you get the appearance you want. Get a good match on the pipes and do a good job welding and you'll hardly be able to see your joint.

As far as bending the stainless I don't know any real slick way to get a mandrel type bend in a home shop. I do have a hydraulic bender pipe bender that I made that will bend the pipe but reduces the inside area in the process. I know it can be mandrel bent as I have a set of stainless Bassani's that are but takes some special eqpt. to do so. I have wrinkle bent pipes before too (heating about 240 deg. of the pipe and then bending in a small increment then moving down about an inch and repeating until you get the radius you want). This works too but I don't think you would like the appearance and it to causes restrictions. Probably best in your situation is to buy prebent mandrel portions then cut and weld accordingly. Only other alternative would be to find someone to mandrel bend sections for you.

Randy

 

Search the web for "stainless exhaust".

Try this link also:

http://stainlesssteelmufflers.com/home.htm

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Do you need to use different or special gas for SS welding? Just curious. Thanks.

 

80/20 mix argon/Co2 is what is recommended to weld SS.

 

>80/20 mix argon/Co2 is what is recommended to weld SS.

You need to use Tri-mix gas for mig welding stainless!! With stainless wire. After sanding the weld down I have found that a wire wheel buffs the weld up good and blends it all together. I went to college to learn this stuff Good luck....


Justin
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>>80/20 mix argon/Co2 is what is recommended to weld SS.
>
>You need to use Tri-mix gas for mig welding stainless!! With
>stainless wire. After sanding the weld down I have found
>that a wire wheel buffs the weld up good and blends it all
>together. I went to college to learn this stuff Good
>luck....
>
>

he's right, if you use 80/20 mix, the weld will turn kinda black looking... it still holds fine, but isn't very good for places where looks count.

another thing is, i'd never weld stainless steel with regular wire.. it may work for some places, but it will rust, and won't hold like it should....

 

Yup, the gas used is a tri-mix! 90% Helium, 7.5% Co2, 2.5% Argon! Why such a high % of helium? Good call! And as long as you use the right wire, L304, L308, L316, and same for the L400 series of stainless steel and wire, etc, stainless is just as easy to weld as mild steel!!! In my opinion, is easier, and a whole lot cleaner! You will know you can weld SS well when the color of the weld, beit wire, tig etc, is yellow gold in color, with a tinge of ocean blue!! Get with it and weld!!!!

 

On dairy milking parlor pipelines they even purge the SS line with helium prior to welding to eliminate any burning/staining that might occur on the inside of the pipe.

For those of you that have that small SS welding job and you are not overly concerned about discoloration around the weld area then go ahead and use what ya got! Alot of us want to do the job here at the home shop and don't want to buy specialty gas and wire for welding small/occaisional SS projects. I regularly use mild steel wire and 75%Argon-25%CO2 to weld stainless. It welds beutifully, is strong and while it may discolor/stain eventually I'd be willing to bet the hog farm that it will never rust thru in your lifetime (or your grandkids for that matter). I tried this years ago just out of necessity on livestock equipment and has proven the test of time in an environment much more demanding (both physically and corrosive) than an exhaust pipe. My theory on the welds' resulting resistance to corrosion is that the weld pool picks up enough nickel from the adjoining metal that it in itself becomes significantly corrosion resistant. Also strength of the weld has NEVER been an issue. I'm not going to say this is the book way of welding stainless but for alot of applications this will work fine and allows the average Joe to do this with the gas/wire he already has in his shop. Give it a try and this approach might "fit the bill."

Randy