wrote in message
...
On Thu, 24 Jul 2014 10:34:48 -0700, wrote:

On Wed, 23 Jul 2014 21:40:07 -0400, wrote:

On Wed, 23 Jul 2014 20:18:48 -0500, "Terry Coombs"
wrote:

Meanie wrote:
I plan to have someone weld 4 sections of a layout using 6061 aluminum
which you can see
here.....https://www.flickr.com/photos/18223943@N06/14542109948/

This corner/section
https://www.flickr.com/photos/182239...n/photostream/
where the two pieces meet at the side, the corners touch. I cut the
other two corners for a flush cut.....
https://www.flickr.com/photos/182239...n/photostream/

Should I cut one side piece to make flush with the other for better
welding or will a good welder be able to fill that in for a secure
job?
Thanks

The first pair , you need to widen the vee a little , give the welder
somewhere to put some filler . The other pair should also touch at the
inside corner , and have about a 60° vee .
If tigging a "V" is not necessarilly required - Autogenous welding
doesn't even need filler (or much filler)
While autogenous welding works well with steel it does not work well
with 6061 aluminum. What happens is that the aluminum tends to hot
crack. This is why a filler metal is needed, the filler is a different
alloy and when mixed with the base metal forms an alloy that is not
sensitive to hot cracking.
Eric
But remember, not all aluminum is 6061, and not all 6061 is T6. And
not all aluminum is welded with a filler that is different in
composition from the base metal..
Welding 6061 structural parts is always second or third choice for me
- much rather use rivetted or bolted construction than welded where
strength is required.
I didn't look -was 6061 speced in the OP's post? If so, my bad.

It was 6061 which is normally welded with 4043. 6061 and 5052 are the two
alloys I am most familiar with welding. You normally weld 6061 with 4043
filler, and 5052 with 5356. I also work a little bit with 7075 which is not
easily weldable, although if there is a way I bet Ernie knows it.