Fin tube

[smithy]

Wow this is a cool fourm now I have a place to ask all my dumb welding questions !

I have a fin tube to build for a customer 8" sch80 6061 t6 alloy 20 feet in lenth with 26 30x30" 1/8" thick fins welded 100% 9" on center
I am considering mig welding the fins on by rotating the tube on blocks and welding both sides of the fin at the same time to avoid distortion as i dont want this to look like a pretsel ~~ any thoughts or suggestions would be a great help

[cutter]

Hi Smithy,

I have no comment or advice on your project but I can say "Howdy & welcome aboard".
After re-reading your post I do have a question: What the heck is this thing for?

[smithy]

a heat exchanger to cool down thich liquid

[lotechman]

Just some thoughts: you will need at least three supporting rollers, one set powered.
You might consider making up four discs exactly the ID of the tube with a 1/8th hole centered in each. With a light at one end you will know right away if you are bending the tube. I am not sure how but you might even be able to rig a cheap laser light.
Can you rig both gun on stands? Just clip the triggers on and go around?
If you screw up and have to repair have you figured out how you are going to remove the porosity or whatever? Nine inches apart is pretty cramped.
It might be an idea to buff everything before assembly then just a light touch with a stainless brush will be all you need?