Bubbles/air in silicon bronze TIG braze?

Stevegannonhandmade · Sat Apr 07, 2018 9:07 pm

Hi,

I'm trying to make a living out of my garage and basement, selling welded Mjolnir and home decor online and at craft shows. I taught myself how to weld, so...you know... I don't really know how to weld. My welds are looking better and better, however...

My TIG brazing with silicon bronze ends up with lots of bubbles/air in the bronze, and I don't know why. This brazing is also pretty sooty....

My welds on mild and stainless are not sooty, nor do they have air in the beads.

I'm using a Miller econo TIG. DC EN.

The econo TIG does not indicate amps... the dial just goes from 0 to 100 (% of full amperage, which changes depending on the setting). So... I used the food pedal to give it enough amps to just start to see the beginnings of a puddle in the steel, and then back off just enough to still get a nice puddle with the bronze, but not melt (much) of the steel.

I'll attempt to attach a pic so you can see how sooty the braze is, and the inclusion of the air. If I use much more heat than I did in the pic I start to melt the base steel (just mild steel).

Thank you in advance for your thoughts and advice.

[img]https://imgur.com/FumWqSF/img]
[url]https://imgur.com/FumWqSF/url]

Stevegannonhandmade · Sun Apr 08, 2018 6:42 am

Sorry... I should add that I'm using 1/16 2% lanthanated tungsten and pure argon, around 15 cfh.

cj737 · Sun Apr 08, 2018 7:08 am

It could be a few things: You may have contaminated the tungsten by dipping into the bronze filler pool, your cup size could be too small and thus you're not getting sufficient coverage, your base metal must be REALLY clean for TIG, and even more so with SilBr, and it could be too much heat is causing the puddle to suck some base metal up into it (and the base is not clean on BOTH sides if you're dealing with thin sheet metal).

Its difficult for me to say exactly what has caused it from the blurry pictures and no further info.

Stevegannonhandmade · Sun Apr 08, 2018 7:10 am

How do I make pictures show up? It's not clear... I'll try again

[img]https://i.imgur.com/FumWqSF.jpg/img]

Stevegannonhandmade · Sun Apr 08, 2018 7:15 am

I still do dip my tungsten more than I'd like, and I change them out... a lot... as soon as I dip them. In this example I'm using 1/8 mild steel, sanded to clean metal on both sides. I was using a #8 cup, and a #8 pyrex cup to see if that helped... both with a new gas lens.

I feel like I'm doing all of the right things... and this is a new tank of argon, however it was happening with the last tank too.

Now I'm off to the Trenton punk rock flea market...

LtBadd · Sun Apr 08, 2018 8:28 am

Stevegannonhandmade wrote:How do I make pictures show up? It's not clear... I'll try again

[img]https://i.imgur.com/FumWqSF.jpg/img]

Steve, maybe this can help...

: uplaod 1.jpg (13.54 KiB) Viewed 2079 times

: step 2 upload.jpg (21.13 KiB) Viewed 2079 times

Mon Apr 09, 2018 1:37 am

you left out the [ on the code.
this is the pic. https://i.imgur.com/FumWqSF.jpg

edit: pic is to big to display on the forum. the above link should send you to it.

Kevin_Holbrook · Mon Apr 09, 2018 10:06 am

looks a little like brass

try welding with AC

Warrenh · Mon Apr 09, 2018 3:15 pm

This is si bronze on naval brass. Use ac with 80% EN. Brass has zinc in it that will burn off and leave holes.

Sent from my SCH-I545 using Tapatalk

Stevegannonhandmade · Mon Apr 09, 2018 4:50 pm

Thank you for your attempts to help with this...

I think I may have found the problem...

I still dip my tungsten, and sometimes that means pops and spits, etc... So... gas lenses are 'used up' and have a lifespan. The problem apparently started after I changed out a collet set, and now... replacing that one seems to have fixed the issue.

I will include that as a troubleshooting measure in the future, before asking for help.

Thank you again!

Steve

I'll (attempt to) post a link to a new pic... 1/4" mild steel, all filler is 1/16", 2 beads silicon bronze, 2 beads stainless filler (409? I was given)... one seems too too much heat?, 1 bead mild steel filler, and one silicon bronze on A/C... seems as if the A/C left some spots of contamination (or perhaps simply made them more visible?), and it is certainly acceptable in my shop. I end up grinding all of the welds on the Mjolnir and large D20's I make with the TIG... most everything else is MIG.

R32Guy · Thu Apr 12, 2018 10:02 pm

Hope the new gas lens resolves your issues. I recall in a video that Jody recommends using AC for silicon bronze Tig brazing. If I recall you can turn the settings to minimal cleaning action if your machine allows. If not the default AC settings should still work fine but it may require a little higher current setting.