tube prep

[that-guy]

i've been cutting and welding aluminum tubing for some time now and was wondering if the finish of the cut makes a difference on the quality of the weld???

now i know that fitup is everything, but i'm not asking about that

to explain further, i have alumunum bends to make intercooler piping for a turbo application. as i only need a portion of a bend, i cut off the excess, de burr the inside edge, then rotate the outside edge on my belt sander. does how fine the belt is make a large impact on the quality of the weld? if so, what grit do you prefer?

 

[rdn2blazer]

Doesn't matter as long as the aluminum is CLEAN. Especially for TIG. I still would stainless steel wire brush it after belt sander debur just to make sure its all good before weld. I would clean the tube with 91% alcohol as well before grinding it.

 

[that-guy]

so the "gouges" left from lets say a 36 grit belt will not differ from the "scratches" left by a 150 grit belt?

 

[blind]

I've had no issues doing it as described. Just be sure to SS brush it. Always SS brush.
Are you using quality aluminum tubing? I've had issues with ebay aluminum not wanting to take a weld.

 

[that-guy]

i don't have any problems with welding the tube, i have done plenty, but i am just sitting here at work thinking up how i can make it better. already i was grinding my tungsten with an aggressive bench grinder wheel, so i got a finer wheel and the arc stability improved, now i'm just thinking about the sanding marks and bevels on my tube and whether or not that can improve

 

[rdn2blazer]

i don't have any problems with welding the tube, i have done plenty, but i am just sitting here at work thinking up how i can make it better. already i was grinding my tungsten with an aggressive bench grinder wheel, so i got a finer wheel and the arc stability improved, now i'm just thinking about the sanding marks and bevels on my tube and whether or not that can improve

Smoother IS better in this situation. Yes I would use finer grit. 36 is very agressive.

 

[machine_punk]

+1 on the 91% to 99% isopropyl alcohol wipe down, followed by a stainless steel brush before welding.

Kev

 

[that-guy]

+1 on the 91% to 99% isopropyl alcohol wipe down, followed by a stainless steel brush before welding.

Kev

what would you suggest? i found up to 220 for my 6x48 belt sander

my plan is to cut each of them down the middle so i have a 3x48 of coarse, and a 3x48 of fine

 

[Fcvapor05]

what would you suggest? i found up to 220 for my 6x48 belt sander

my plan is to cut each of them down the middle so i have a 3x48 of coarse, and a 3x48 of fine

I'm with whoever said it does make a difference. A very roughly deburred edge won't weld quite as nice as a smooth one will. It's a small difference but if you're after the most beautiful cosmetic welds, that stuff matters.

I'd suggest using an OD deburring tool instead of the sandpaper/grinder method. If you don't want to do that, use the finest grit you can get, then wire brush + IPA wipe as others have suggested.