Aluminum tig joint problem.

[monte55]

I am trying to tig two flat pieces of .125" aluminum together with a tight butt seam. When the puddle starts each piece melts and pull away from the other
creating a void. It's like they're repelling each other. The only way to stop it from continuing is to get some filler to bridge the gap and go on. I've seen welds without filler before. Is it normal for the edges to do this? I don't see this as being any different than doing spot welds that do the same for me.
The pieces are flat on a table when welding.
Nick

[Laiky]

When i have had that problem its because of lack of cleaning and fitup. The faces of the butt don't get a lot of arc cleaning, when the metal melts the surface tension causes metal to start to round, since there is probably oxide between them if they are barely touching they wont come together. I clean well and start with low power to get more cleaning while heating up, if you can keep the coupons pushing against each other it helps too. Or you can just add filler.

[shoprat]

i dont think you can fuse weld aluminum,but i am not positive.i have always used filler rod.

[Fishy Jim]

Sure you can. I do it tacking all the time.

[projectwelder]

Usually tigging Aluminum requires filler rod. If you want to fuse up with only base, bend up a flange on either side of the joint the thickness of the material (i.e. .125 flange for .125 Al). Heat with your tig torch and the flanges will melt filling the gap.

John

[FusionKing]

I am trying to tig two flat pieces of .125" aluminum together with a tight butt seam. When the puddle starts each piece melts and pull away from the other
creating a void. It's like they're repelling each other. The only way to stop it from continuing is to get some filler to bridge the gap and go on. I've seen welds without filler before. Is it normal for the edges to do this? I don't see this as being any different than doing spot welds that do the same for me.
The pieces are flat on a table when welding.
Nick

The answer to this question depends more on the type of joint. An outside corner would be better to learn for tacking without filler. To do your butt weld, clamping somehow would be more likely than not also.
Aluminum expands greatly also, so if you are using "strips" then you'd
need to get the first couple of tacks done and get the two parts shrinking from previous tacks as you move on. You can see it grow apart and shrink together as you go. Shrinking and growing is something you learn to count on with aluminum...it is much more pronounced than steel IMO
There are some things you just have to struggle with untill you get good.
I don't tack much without filler even tho I have worked in factories that we did it a lot...I simply do not like the results myself. They crack easy. YMMV

[c wagner]

Yeah we tack aluminum all day long without filler BUT only on outside corners.
FuisionKing is right, tacks without filler do crack easily so it really depends what your doing and the shrinkage can be a big issue with aluminum welding. We've had parts 8ft long shrink almost an 1/8" Not good if you haven't planned for it.

[ridesideways]

while you can get aluminum to fuse without filler if everything is perfectly clean and the fit up is perfect, it is much easier with filler. so i think the best advice is to just use filler-- the weld will be easier to make and stronger as well.

[Marcel Bauer]

The material must be FRESHLY cleaned, and I agree, use filler.


HEY! My first post! Hi kids!!!!!CHEERS!

[griff01]

i dont think you can fuse weld aluminum,but i am not positive.i have always used filler rod.

Sure you can! It is a very common process when tacking up parts.

Griff