[metaldreams]

I am working on 3/16 aluminum butt joint. i find that i can get great looking beads but my penetration is incomplete. When i hover in place longer i get two humps of aluminum on the back side of the joint but the center on the back side is not fused? How can the sides melt before the aluminum in the middle? Which brings me to my ultimate question of how do you know when to advance the torch or stay longer in one spot when you are welding aluminum? Thanks. Hope that makes sense.

[LtBadd]

What your seeing on the back side, the way it looks like the center of the joint doesn't fuse is normal If you purge the back side this would improve.

As to when to advance, this requires a lot of practice. Sorry I can't give a better answer, this is the hardest TIG test I've taken, getting penetration while controlling the drop thru, timing and consistency and lots of hood time.

Best to have the force on your side for this one

[Oscar]

Are you beveling the joint?

[metaldreams]

Are you beveling the joint?

No i am not beveling. I am still trying to do what i see in the videos where people have success without beveling. I try to look for signs like the puddle sinking and keyholing (I think that is what it is called) but i continue to be amazed at my lack of complete fusion in the back. It is more of a learning experience for me than out of necessity.

[metaldreams]

What your seeing on the back side, the way it looks like the center of the joint doesn't fuse is normal If you purge the back side this would improve.

Thanks for that. I didn't know that would make a difference.

[Oscar]

Are you beveling the joint?

No i am not beveling. I am still trying to do what i see in the videos where people have success without beveling. I try to look for signs like the puddle sinking and keyholing (I think that is what it is called) but i continue to be amazed at my lack of complete fusion in the back. It is more of a learning experience for me than out of necessity.

I haven't seen back-side fusion on non-beveled 3/16" on youtube videos. Seen it on 1/8" or thinner.

[Oscar]

Here is one where you can see the advantages of both back-purging and using a gap. FF to 3:00 mark.
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Here is another one, showing how much a bevel will help with thick aluminum. Note the different appearance due to no gap/back-purge. FF to 12:30 mark. Also note that he is really driving the arc into the center of the joint via a very high AC frequency. If I had to guess, he was up over 250Hz.
svSi5_ZLFn4

[Otto Nobedder]

Hell, I didn't know Fieldres had a channel!

Thanks,

Steve

[Olivero]

3/16" non beveled. Good luck getting through that, would take a serous amount of heat with all the heat transfer to the rest of the aluminum. Aluminum is a great conductor of energy so it takes more heat to get it going as I am sure you know. But it also makes it able to transfer the heat around itself much faster and so it requires more heat.

I would just bevel it and then you can bite through it.

[metaldreams]

thanks everyone. this had been really helpful. Love the videos. I have never seen the backside of the weld develop real time.

[pgk]

Damn! Fieldres has got some major pipe welding skills!!

Pete