setzep

Max, thanks for all the help. I feel more confident now after starting this thread, I would have never known to backpurge the stainless and probably would have just tried to weld it like it was regular steel. But I'm a little unclear how you backpurge flat welds or butt welds on plate. Do you just make a little "house" and run a gas line into it on the back side from where you are welding? Also does "fusion" welding work with the 304L? I've seen it done to steel before where you don't use any filler rod and simply melt the two pieces of metal together.

Thanks for all the help again!

Cam

Maxthe7man

Yes exactly, you build a little box around it so the gas pools around the weld, not neccesary though if you can hide the backside of the weld, some of the stainless mufflers now on the market are welded without backpurging, if you look inside them, you can see the big ugly gobs of backside crystal, which is actually referred to as "dropthrough"...
You can fusion weld stainless, in fact thats how its done with tig, you finish the edges of the pipe so its a perfect fit and with a tig you can just melt the two edges together,resulting in those nice mini bead welds you see on the japanese HP parts and stuff, I only used a bit of filler rod when I had a slight gap to close or there was part I wanted to build up for strength..
Some people like to buff the welds out on stainless so it looks mandrel bent one peice like, however I like the "goldish" stain the welds give the pipe..Max

setzep

Thats what I plan on using, a TIG. My friend just got this new ESAB heliarc that he payed god knows how much money for...
It's good to see that fusion welding it together is acctually the preferd method, will backpurging still be needed? Also what filler rod will I need to "fill the gaps", would you know off hand for the 304L? I think he has some 308 rod already, will that work?
This should be a fun project for me and when I get it done I will be sure to post the pictures for you to tell me what I did wrong

thanks

Cam

rotarygod

iTrader: (1)

I have some of the schedule 40 steel pipe lying around and am building turbo headers using it. It is plenty strong enough to withstand the temperatures since it is so thick. For many years this material was used on custom headers on various kinds of race cars that seemed to last forever. Just so no one argues the point I understand that there are temperature differences between the rotary and a piston motor. Check out www.sdsefi.com . They have info on how to build turbo headers using these weld els. They are really cheap. Only a couple of bucks a piece. The straight pieces are cut to length and are around 40 cents a pound. In the end the whole assembly weighs about as much as a cast iron unit but it is almost as strong. SSS Steel in Houston sells these parts. I also have some stainless from Burns Stainless that I ordered but that stuff is hard to work with although I do love the way they look.

Fred