welding 11 gauge stainless plate

[11b]

I have 2 304L stainless cylinders that have been rolled and I have to weld the seams together to make tanks. I will of course weld bottoms on also. It is just a butt weld but the tank is for beer and I am going to tig it from the inside out as not to risk contamination. However, I want the outside to look nice also. My problem is figuring out a way to get argon on the back or really outside of the tank. I was thinking taking a copper pipe sawed length ways and trying to clamp that to the joint and welding it with argon flowing through it. Does anyone have any other ideas that would be faster and easier. Thank you for thoughts on this.

[dave powelson]

shielding ss outside surface

I have 2 304L stainless cylinders that have been rolled and I have to weld the seams together to make tanks. I will of course weld bottoms on also. It is just a butt weld but the tank is for beer and I am going to tig it from the inside out as not to risk contamination. However, I want the outside to look nice also. My problem is figuring out a way to get argon on the back or really outside of the tank. I was thinking taking a copper pipe sawed length ways and trying to clamp that to the joint and welding it with argon flowing through it. Does anyone have any other ideas that would be faster and easier. Thank you for thoughts on this.

Ceramic backing tape
Solarflux

No shielding or backing will not make an overheated puddle look good on the back side.
Suggest you do some flat test pieces to establish weld parameters, method and
torch technique---and the joint prep to be used.

[11b]

I like the ceramic backing tape idea but that stuff is pricey! You have had good luck with Solar flux?

[Ltbadd]

Cap off the ends, purge the inside, make the weld from the outside, if you don't get 100% then you can probably get away with a lower amp weld from the inside without burning thru to the OD.

[dave powelson]

does solar flux 'work?'

I like the ceramic backing tape idea but that stuff is pricey! You have had good luck with Solar flux?

This leaves a glassy residue which can be cleaned off on the outside face,
which is no big deal. mix the flux with methanol--not isopropanol--Heet gas
dryer is available in either.

I've had good results with solar flux--but it's not a question of luck.
[Solar flux was developed under secret patent in WW2, specifically for gas
welding SS exhaust & turbo components of US bombers. It's got a track record.]

To repeat 'No shielding or backing will not make an overheated puddle look good on the back side.
Suggest you do some flat test pieces to establish weld parameters, method and torch technique---and the joint prep to be used.'
The weld seam needs to be done in small steps, back stepping the welds,
stopping to cool/force-cool then resume. Lots of preliminary tacks using
a little filler before the weld out and that joint will need some form of prep.
The welding will produce a cylinder that is not round or necessarily straight.

The heat control and fastest speed possible while running the puddle is critical
to keeping heat input to minimum.
You first need to practice with flat stuff.

[MMW]

Weld the inside while purging the outside can be done by taping aluminum foil over the outside. Leave a space between the joint & foil to fill with argon & tape it far enough away so the heat won't affect the tape. Just tape the hose in one end & leave a small opening at the other. Very cheap solution.

[11b]

Great suggestions! OK I was thinking trying this. A piece of angle clamped on outside and capped at one end with argon flowing through it to the other end. Then welding from inside. I like the back step idea for sure. I was thinking an 1/8th inch gap and laying 1/8th filler in. On the other hand I was wondering about a fusion weld but I dont think I will get good penetration on this. It measures out at .135 inches. I would have to put way to much heat in. I have been trying some different stuff even my pulsor.

[11b]

Cap off the ends, purge the inside, make the weld from the outside, if you don't get 100% then you can probably get away with a lower amp weld from the inside without burning thru to the OD.

I also thought of that but 24inches is a lot of argon! Do you think that I could do that from the inside and if I dont get full pen hit it from the outside without sugaring?

[dave powelson]

joint prep

Great suggestions! OK I was thinking trying this. A piece of angle clamped on outside and capped at one end with argon flowing through it to the other end. Then welding from inside. I like the back step idea for sure. I was thinking an 1/8th inch gap and laying 1/8th filler in. On the other hand I was wondering about a fusion weld but I dont think I will get good penetration on this. It measures out at .135 inches. I would have to put way to much heat in. I have been trying some different stuff even my pulsor.

I was thinking an 1/8th inch gap and laying 1/8th filler in.

Butt the ends tight to each other after chamfering maybe .050 on all four edges for weldout from both sides.

From the way your questions shotgun around, I think this is an exercise in futility. Best approach in that case is just to weld stuff up
with results less than satisfactory, which is an invaluable lesson in itself.

[11b]

Yup that is what I did except left the root at 1/8th gap, 115amps, 3/32 308L rod, 3/32 Lanth tung pulse on the peddle, lots of copper chill bars, monster gas lens. I wish the purge would have worked better but got er done and is very nice. The metal was .135 so it was on the edge of to bevel or not, I would bevel the next one. Thank you for the suggestions gentlemen.