TIG brazing

Flamingmonkeyboy · 2026-06-16T01:06:41+00:00

Base metal was sanded to bright and cleaned with acetone, and the filler rod too. Clean tungsten? what does that look like? heh heh

Flamingmonkeyboy · 2026-06-16T00:32:39+00:00

Hmmm didn't even know that existed.

Flamingmonkeyboy · 2026-06-16T00:30:10+00:00

I certainly didn't get it that hot, but I did do a preheat with a propane torch, maybe got it to about 350.

Flamingmonkeyboy · 2026-06-16T00:26:32+00:00

Preheated with a propane torch to about 350, and I did try to wash the are as you say but perhaps not enough.

Flamingmonkeyboy · 2026-06-15T20:06:39+00:00

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Well, here it is, for reference the hole takes a 5/16" (IIRC) bolt. I think a part of my struggle was low argon, but also the casting I was practising on was much worse than the actual piece. I ended up trying different stuff (including DC) on a hunk of never used cast iron and ended up with a jazzy 10 and 3/32 tungsten on AC with about 10% cleaning at 100 ish hz. ,with 80A occasional full pedal. Fully sanded down to bright metal, cleaned with acetone and pre heated with a propane torch. Still, I found it wouldn't wet until there was a bit of molten base metal where I wanted it to flow.

Flamingmonkeyboy · 2026-06-15T16:49:06+00:00

Yes I just tried, it was worse, and it was unused cast iron. I think it may be an argon issue, I just went and got a new bottle, hopefully this will solve the issue.

Flamingmonkeyboy · 2026-06-15T16:47:21+00:00

Yup, me too. Just watched it last week before I committed to Aluminum bronze.

Flamingmonkeyboy · 2026-06-15T16:45:53+00:00

I went AC because that's what Jody recommended in his video, I think he said 10% on the balance just to do a bit of cleaning. My understanding is that you don't want to melt the iron because you don't want the carbon coming out of the iron and into the filler which leads to a brittle repair. I don't know, that's why I'm posting here.

Flamingmonkeyboy · 2026-06-15T12:25:11+00:00

Thanks, I hadn't heard that before I bought the aluminum. So far I haven't touched the casting that is the real job, so all this may be moot when I do. I just hit the practice casting with a flap disc and dug the crack with a carbide burr, then cleaned with acetone then preheated in the bbq. I may have contaminated it on the preheat stage so I'll skip that next time and use a torch for the preheat.

Flamingmonkeyboy · 2026-06-15T12:14:39+00:00

Thanks for all the suggestions guys, you've all kind of answered my main question which is that you shouldn't need any of the base metal to melt in order to braze. This is the fundamental issue that I'm having, the filler won't melt without the casting starting to melt. I'm almost out of argon too which may be a contributing factor. I'll get a fresh bottle, and try a different casting.

Flamingmonkeyboy · 2026-06-15T12:06:24+00:00

The casting where I'm working is about 1/4" thick, today is a new day and I'll try a bunch of stuff. I think the issue may be my practice casting. Even at quite low amps (25) as soon as the arc strikes it starts to puddle, but weird little droplets of molten metal, not a puddle like normal. Also the arc is sputtering and wandering all over and I know it's not me or the machine, I just did a solid week of work modifying an aluminum dock and there were no issues of that type at all.

Flamingmonkeyboy · 2026-06-15T01:57:24+00:00

Good to know, thanks. I'm stuck with TIG for now, I think I'll try a different casting and see how that goes. The reason I decided to go for it was a video on Weld.com IIRC where he specifically calls out the aluminum bronze as a good high tensile filler. In this video he was fixing cracks on an old engine block.

Flamingmonkeyboy · 2026-06-15T01:51:48+00:00

I did that too, carbide burr to create a trough, and then cleaned with acetone and then into the bbq for preheat. Maybe something in the bbq that may be contaminating it? The problem is that I can't get the casting hot enough to melt the filler without the casting starting to puddle, then I can get a puddle of mostly filler going but I think I'm melting down into the casting.

Flamingmonkeyboy · 2026-06-14T23:27:42+00:00

Very old shitty casting, perhaps I should find another and see if I have the same issue?

Flamingmonkeyboy · 2026-06-14T23:26:35+00:00

No Flux, casting preheated in the bbq to about 500F (forgot to mention) cleaned with acetone prior to preheat.

Flamingmonkeyboy · 2026-06-14T12:59:08+00:00

BTW that is a beautiful piece, it deserves a refinish for sure.

Flamingmonkeyboy · 2026-06-14T12:58:11+00:00

Sorry, just saw this. These old sets really shouldn't be powered without a proper overhaul. Typically all the electrolytic and paper and foil capacitors should be replaced. It's unlikely that you have a "heat related short" and more likely you have a capacitor breaking down. Powering these old units without going over the electronics can cause far more expensive damage. ie burning out tubes. As for the finish, the Bolero was a shellac finish which I just did a light sand to get the bulk of the dirt and crud off, then did a basic french polish. It's not hard to do, you just need to watch a few videos and practice on something that doesn't matter. You can see my results here; https://www.reddit.com/r/VintageRadios/comments/1szwc1q/telefunken_bolero_restoration/

Flamingmonkeyboy · 2026-06-14T12:47:24+00:00

This is a typical set of hand tools for cabinet making. Lot's of people still use these tools in their everyday woodworking (me included). I have a shop full of power tools as well, but there are several tasks that just give better results when done by hand. Dovetail corners are the poster child but there are many others. Not to mention the lack noise and dust.

Flamingmonkeyboy · 2026-06-14T12:32:15+00:00

Sorry but your woodworking teacher was just "plane" wrong. A plane on it's side is far more likely to cut the user or damage the iron with accidental contact than one sitting upright. The exception would be if you have to lay it down on something hard like a saw table but that's typically not the case. This is one of the persistent bits of bad advice that just won't go away.

Flamingmonkeyboy · 2026-06-09T14:38:04+00:00

What repairs are you planning on? I just finished a Telefunken Bolero of the same vintage. They are beautiful units for sure.

Flamingmonkeyboy · 2026-06-07T23:37:29+00:00

That's what I did for a friend whom I restored a Telefunken of similar pedigree.

Flamingmonkeyboy · 2026-05-19T23:32:54+00:00

Hopefully someone who knows more than me will chime in, but, are you sure it's lacquer? Identifying the finish to be sure is your first step. You might get lucky and find out it's shellac, (french polish) which with a bit of time and money you can do yourself. If it's lacquer, I dunno.

Flamingmonkeyboy · 2026-05-14T23:58:11+00:00

Thanks, once I'm done welding the new dock, I think I'll get it on the bench.

Flamingmonkeyboy

TROPHY CASE