Aluminum mig burn through

[Dlwii]

I'm a new enthusiast to the welding game. I chose a hard place to start. Building a bracket out of 1/8" aluminum. I've burned a lot of wire. Last night I finally laid a decent weld that penetrated. Before, theough a ying around with settings and living on this forum, I couldnt get any penetration. The wire material would just blob up on the plate. Now that I have something that resembles a
real weld, I'm fighting burn through. The unit suggests a setting of 5:70. I back off that to 4/65 as soon as the metal heats up, 2" of weld or so. It's still melting however and the puddle sinks as it pushes out the back. It seems to me that I read somewhere to clamp a block to the back of it (i'm welding 2 pieces at a 90 degree angle, the top piece resting on the bottom piece, fillet). Would this help and if so, of what material should the backing block be made of?

['Stang]

I'm a new enthusiast to the welding game. I chose a hard place to start. Building a bracket out of 1/8" aluminum. I've burned a lot of wire. Last night I finally laid a decent weld that penetrated. Before, theough a ying around with settings and living on this forum, I couldnt get any penetration. The wire material would just blob up on the plate. Now that I have something that resembles a
real weld, I'm fighting burn through. The unit suggests a setting of 5:70. I back off that to 4/65 as soon as the metal heats up, 2" of weld or so. It's still melting however and the puddle sinks as it pushes out the back. It seems to me that I read somewhere to clamp a block to the back of it (i'm welding 2 pieces at a 90 degree angle, the top piece resting on the bottom piece, fillet). Would this help and if so, of what material should the backing block be made of?

You didn't give a lot of information about the equipment you are using. From the settings that you gave, I would assume that it is a light duty hobby type machine. I would also guess that you are using a spool gun for your aluminum welding.

Going from there, the burn thru issue-you are either running too hot, or moving too slow. I run aluminum every day at work, and burn thru is a common problem. It could also be you gun angle. If you let your angle wander to the top plate on a t-joint-it will burn through the thinner material.

As for the piling up of material when you light up-that can be from too much wire speed, or moving too fast. Let the puddle form-then keep your wire on the leading edge. A long stick-out will also cause a pile-up of the bead. You will preheat the wire, and it doesn't fuse with the base material.

[M J Mauer]

Welcome to the forum.

[kevin]

watch the surrounding metal in front of the puddle, when it gets a shiney, wet look, it is staring to drop so back off with the heat