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What's up with this?

Posted: Mon Sep 11, 2017 7:48 pm
by jroark
Does anything look wrong with this weld to anybody? After I grind it down smooth it has these little dimples in it and I don't know why! One weld looks like it would be perfect and it has these dimples and a different weld looks like it would be bad and it turns out fine. I was wondering if maybe I'm adding filler too soon or too much at one time? What do y'all think?

Re: What's up with this?

Posted: Tue Sep 12, 2017 2:49 pm
by Oni
I only see one picture. If you are talking about the dimple at the end of the weld, that is from tapering off with the foot pedal to quickly. When you get to the end give the puddle an extra dip and let off the foot pedal a little slower while giving the torch a small stirring motion. That should help.

Re: What's up with this?

Posted: Tue Sep 12, 2017 7:17 pm
by raticus
is this pic just an optical illusion, or is that weld bead gigantic in comparison to the base metals? it looks like 1/2" of weld on 20 gauge sheet.... Maybe that's your issue, way too much weld filler and it's doing all kinds of weird flow action before it cools

Re: What's up with this?

Posted: Tue Sep 12, 2017 9:34 pm
by jroark
Sorry guys. I was using this weld as a before grinding view. It's not that big. It's 1/8" material. The little divot at the end wasn't the issue. I think after it's ground it seems to have some porosity hidden under it and I'm not sure why. I brush it and use acetone but I guess it's still not clean enough.

Re: What's up with this?

Posted: Tue Sep 12, 2017 11:11 pm
by thespian
jroark wrote:Sorry guys. I was using this weld as a before grinding view. It's not that big. It's 1/8" material. The little divot at the end wasn't the issue. I think after it's ground it seems to have some porosity hidden under it and I'm not sure why. I brush it and use acetone but I guess it's still not clean enough.
Make sure you clean both sides of the metal.

Re: What's up with this?

Posted: Wed Sep 13, 2017 9:49 am
by cj737
You should adjust your AC balance, and make sure when you add filler, that you're getting the rod into the root of the fillet weld. It's been my experience, that aluminum due to its different behavior with penetration, is more susceptible to creating these pockets of porosity. It's tricky stuff to weld properly for sure-

Re: What's up with this?

Posted: Wed Sep 13, 2017 8:58 pm
by Jakedaawg
Not that I can offer any help, but for learning purposes could you post a pic of the post grind issue you speak of?

Re: What's up with this?

Posted: Wed Sep 13, 2017 9:15 pm
by Poland308
I'm also curious to find out what your using to grind? Is it possible that your grinding device is getting loaded up by the aluminum? This can cause odd looking results when grinding in the surface finish.

Re: What's up with this?

Posted: Thu Sep 14, 2017 12:05 am
by jroark
I'll try to get a post grind pic. I'm using a Carborundum flap disc and something like a scotch brite disc. It's tubing so I can't get to both sides of the material. Thanks for the tip on putting the filler in the root. I could have an issue with my technique. I'm really not super experienced as far as having lots of years of practice.