[Arno]

I heard of a product called "solar flux" that you can apply to the back of the weld so that penetration doesn't result in sugaring, but not sure how it works.

It's a powder that you mix into a paste using methanol, let it set up and apply to the back of the joint. You then weld it as normal and the flux on the back creates both a protecting gas layer, as well as turning into a kind of molten glass to seal the back.

Works quite decent in situations where the glass-like residue left is not an issue. Aka. can not use it in sanitary/food production, but for instance to protect the back of stainless in a bigger exhaust parts like silencer bodies that can take lots of argon to purge properly it can be a nice option to have in the toolbox.

Bye, Arno.

[taiwanluthiers]

I think I'd like to obtain some solar flux, I'm not able to find any copies of it in China but I see some other brands of solar flux that isn't quite so expensive.

I think I can try for a full pen if I'm practicing, and if I have to purge, then I'll purge, but otherwise I think solar flux is a good practice.

Here's some welding practice... I've been practicing on big thick aluminum blocks because it was all I could get, and I keep having problems. So I found this scrap heat sink and I'm practicing on a piece that's about 3mm thick. The first one was kinda crap because I used too much amps, 100A was plenty, in fact I could dial it back a bit. I had to move towards the end as the aluminum heats up because I don't have any foot pedal so I'm relying on movement to control heat... Frequency is 100Hz, 20 ac balance because I cleaned the piece really well prior to welding.

PXL_20240115_101542075.MP.jpg (250.43 KiB) Viewed 2523 times

Laying beads on a piece of medium carbon steel. 2mm filler. Steel is 10mm thick. I had it at 120 amps and I think I could reduce the heat too.

PXL_20240115_101527138.jpg (299.39 KiB) Viewed 2523 times

I hope I did ok.

I used a #8 gas lens, and 5 liters per minute of gas.

[BillE.Dee]

what I see is dirty material unless the camera angle is bad. clean the millscale OFF to bright shiny material. You probably want another dab in between the dabs you have. hold the torch so you have to peek around to see the tip of the tungsten while pushing the puddle.
try just running some beads without filler to get the feel of the machine. hold the tungsten just a little bit above the material so you can scooch the filler under the tungsten, yes, that close. when you turn the material over, you should be looking at a mirror image of the beads.

[taiwanluthiers]

what I see is dirty material unless the camera angle is bad. clean the millscale OFF to bright shiny material. You probably want another dab in between the dabs you have. hold the torch so you have to peek around to see the tip of the tungsten while pushing the puddle.
try just running some beads without filler to get the feel of the machine. hold the tungsten just a little bit above the material so you can scooch the filler under the tungsten, yes, that close. when you turn the material over, you should be looking at a mirror image of the beads.

No, the material is clean, had to do some very aggressive grinding to get the mill scale off as the material is off cuts from billets and it had sat on the ground rusting, and I not only had to grind the mill scale off, but also the saw marks.

It's also about 10mm thick, I chose thick materials so I can concentrate on laying down beads, and not material warping or whatever.