Brazing & Brass Rod question/problem...

Another newbie in brazing,

Little question after testing brazing with bronze.

I have try 2 types of bronze rod, the first one is a 3/32 flux coated (Lincoln Electric) bought at Canadian Tire. I have no problem to braze with that. Flow really well and get stuck to the metal like it supose to! hehe! I am also able to control the flow pretty well on that one.. But on the second rod type....


Second rod is a 1/16 not covered with flux, so i use a paste flux ( Bohemian / Cycle Design LFB ). I've heat that flux until it turn grey and start to be like a plastic finish, apply my bronze rod but... It make a drop, but the drop wont go on the metal part and get stuck on the rod. Finally able to drop the drop on the metal piece, it slip around the tube and fall beside somewhere on the table.. So it dont wanna sitck on the metal!

What i am doing wrong with that second set up?

It sounds like you may not be pre-heating the steel enough. If the bronze hits it and rolls it is because the rod is hot and the steel cold (causing it to re-cool, bead, and fall down).

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Originally Posted by Eric Estlund

It sounds like you may not be pre-heating the steel enough. If the bronze hits it and rolls it is because the rod is hot and the steel cold (causing it to re-cool, bead, and fall down).

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Thanks a lot for the anwser, i will try to pre-heat the steel a little bit more somewhere on my next pratice.. . This happen only on non-coated flux rod that you have to pre-heat the steel/flux more..?

Use the color of the steel more than the state of the flux as your indicator of temperature while brass brazing. The steel needs to be at the same temp as the melting point of the brass. Like Eric said, the steel wasn't warm enough.

So i've try back tonight.... I'm better with the flux paste set-up now! I pre-heated more the steel and you where right! It work! So i am happy about that, but now, it was really hard to have the bronze flow where i was trying to bring it. The bronze was flowing well out of the rod and stick well on the steel, but was stuck or just like getting cooler really fast once on the steel, still if i was putting more energy ''heat'' on that part! Result, small balls of bronze on the steel....

I'm using a #0 nozzle, is that enough? Was a canti braze on.

https://lh5.googleusercontent.com/-S...k/IMAG1179.jpg

https://lh5.googleusercontent.com/-U...0/IMAG1178.jpg

Looks like you need more heat still. For the flow step (what i do first) the rod should suck right in between the two pieces.The fillet step is done a touch cooler but the rod still should flow onto the joint, just not as quick as water.

Do you have a huge supply of bike bits to be using them to learn on? Most might just use pieces of scrap to learn with, being cheaper. Have you tried to make towers of brass standing up off a bit of steel? Have you tried to flow brass under a plate or sleeve? have you seen how hot steel need to get to burn a hole through it? Andy.

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Looks like you need more heat still. For the flow step (what i do first) the rod should suck right in between the two pieces.The fillet step is done a touch cooler but the rod still should flow onto the joint, just not as quick as water.

Do you have a huge supply of bike bits to be using them to learn on? Most might just use pieces of scrap to learn with, being cheaper. Have you tried to make towers of brass standing up off a bit of steel? Have you tried to flow brass under a plate or sleeve? have you seen how hot steel need to get to burn a hole through it? Andy.

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For bike bits, i've just cut an old cheap and damage frame and trying stuff on it. But i will try yours suggestions. Need more oxygen..

Trembo,

I appreciate you trying but this may be one of those things you just have to see done a couple of times along with an instructor to get down right. We could diagnose all day what is wrong but we don't really know what you are doing. It's like trying to teach you to play an instrument online.

I know I am biased, but try and find someone nearby, maybe a community college or a framebuilder or metal artist or one of the great options for learning on the east coast of the U.S. to help you. This is one of those things that takes two hours with someone knowledgeable and pretty much forever without.

+1 to Dave's post.

You want a pretty neutral flame when brazing. So more O isn't your solution unless your flame has been a carburizing one all along. Do you know the look of the flame/gas mix types? If your flame is set to neutral and you don't have enough heat in the work pieces you need to turn up both gasses or spend more preheat time or go to a bigger tip. Andy.

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Originally Posted by Andrew R Stewart

So more O isn't your solution unless your flame has been a carburizing one all along.

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I think he meant he ran out of oxygen and needs to refill the tank.

Shirk- A reread makes me think you're correct. But it's hard to discern nuance without context or audio. This wouldn't be the first time I've gone down the path of needless questioning. Andy.

What you don't speak French Canadian writing in English??? :)

My girlfriend is also from Montreal, her first two languages are French and Czech, with English being learned much later in grade school. Lots of subtle phrasing differences from the French to English to pick up on.

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I think he meant he ran out of oxygen and needs to refill the tank.

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Your right, i just ran out of O. Sorry!

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Tremdo,

I appreciate you trying but this may be one of those things you just have to see done a couple of times along with an instructor to get down right. We could diagnose all day what is wrong but we don't really know what you are doing. It's like trying to teach you to play an instrument online.

I know I am biased, but try and find someone nearby, maybe a community college or a framebuilder or metal artist or one of the great options for learning on the east coast of the U.S. to help you. This is one of those things that takes two hours with someone knowledgeable and pretty much forever without.

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I know youre right. Of corse i don't want to bug you guys with that. I'm just exiting and want so much. One question is bringing another one... But you know, with all those anwsers i allready know a tiny little more where to go with heating..

Il just say thanks everyone for your informations.

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What you don't speak French Canadian writing in English??? :)

My girlfriend is also from Montreal, her first two languages are French and Czech, with English being learned much later in grade school. Lots of subtle phrasing differences from the French to English to pick up on.

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Yep, my first language is french. So that is why some of my sentences is maybe a little wrong.. or confusing!

Those of us who are dyslexic sometimes problems have. Andy.