Alu weldinig

[Boss]

When Alu welding 2MM checker plate corner welds, I noticed tha I managed to melt the Alu prior to even getting a bead in, any reason why this happens?

I have the settings correctly since when I try to weld on the same piece but not two pieces togther, but simple a flat pieces to make a bead on the bead is perfect.

This problem only happens when am welding two pieces togther.

[dyn88]

make sure the surface you are welding is cleaned immediately before welding. The layer of oxidation that forms on aluminum melts at a higher temperature than the metal itself. clean thoroughly with a stainless wire brush.

[rb455ho]

I agree to thoroughly clean with wire brush and acetone. Are these welds on the inside of the corner or the outside? What kind of machine do you have and remember it is always easier to lay down a bead in the middle of a piece because of more material surrounding the bead which yields better heat dissipation. You might need to adjust your settings or torch position for the corners.

[Blown S-10]

its probably a few things. but 1 important one = make sure you have it fit up as close as possible. by that i mean a .001" gap would be pretty good, .000 would be much better.

[rb455ho]

Blown is absolutely correct. If you have a gap your done. It must fit as flush as possible. You can also try some angle iron backing to help dissipate the heat.

[fun4now]

Boss

maybee i'm missing somthing but what is the problem with getting a fushion weld prior to adding filler. lots of outside corner welds are done without filler.you want to melt the base matereal prior to adding filler .

[rb455ho]

Fun4now, I believe he is having a burnback problem. A corner is easier to tack if it is 1/2 of a T-joint on the inside and a 90 deg butt joint on the outside. If you have a corner where only the inside edges are touching there is very little material actually mating up with one another this makes burnback a problem. I would tack it on the inside with some heat sinks on the outside then do the outside. I hope this makes sense. How can one illustrate on this forum import from Autocad or what?

[fun4now]

yep i was missing somthing

i misunderstood his problem.

thanks rb455ho i get it now.

How can one illustrate on this forum import from Autocad or what?
most just draw it in windows paint and post it as a picture.

[arcdawg]

the OXIDE thats on aluminum melts at 3000* and aluminum itself melts at 1200* so you have to have the heat cranked to get through the oxide and then you have already gotten the base too hot and you just end up with the stinky side of the stick

i take the tig torch and go around a little to burn off some of the oxide before i weld it ..........try a circle circle dab manuaver !

oh yeah you can write that check out to the ARCDAWGS Z71 FUND !

DAWG

[Mike W]

I believe Boss is talking about tig not mig. You have to get the two pieces fused together at the start and then you will have no trouble. I can separate two pieces of .064 by 1/16" and weld them together ok once I make a good start.

[HAWK]

This may not be applicable in your application, but you might try it. A high pulse rate with a very narrow arc on such joints can do wonders. I use 300 PPS at 200HZ.

[rb455ho]

Boss, how did your 2mm corners come out were you able to get the results you were looking for?

[HAWK]

Fun4now, I believe he is having a burnback problem. A corner is easier to tack if it is 1/2 of a T-joint on the inside and a 90 deg butt joint on the outside. If you have a corner where only the inside edges are touching there is very little material actually mating up with one another this makes burnback a problem. I would tack it on the inside with some heat sinks on the outside then do the outside. I hope this makes sense. How can one illustrate on this forum import from Autocad or what?

Rob,

MS paint as FUN4NOW suggested or Adobe Acrobat also works. The CAD file will be too large for the forum as each file is limited to 100KB. Also they are no supported. You could post a link to a site where the drawings are located if you are hosting them on a site.

[aphexafx]

Geek Tip: Open your CAD file in whatever design software you use and position/zoom it for a good view. Then press your [Print Screen/SysRequest] key (usually above the Insert key on your keyboard). This copies your screen into memory as an image. Open whatever paint/imaging software you use, paste it, and then simply save it as a JPEG that you can post here and everyone can view.

This asssumes you're using Windows, BTW.

[Boss]

Wow, I did not expect this much feedback, I will try out you suggestions this weekend.

P.S. the machine is a Synchrowave 180SD, the settings were 120amp 16/17 GFlow. I think the problem could have been realted to the Ac balance control, as in I had the settting set to more penetration as opposed to to more cleaning.

Will try it out, also noted, that the parts where not properly aligned at that point, just was trying it out, did not realise it has such an impact.