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Silver brazing rods

PostPosted: Fri Oct 14, 2016 10:43 pm
by Knocklofty
Hi folks, just looking at 56 silver rods , does anyone have a preference for fluxed or unfluxed rods
Thanks

Re: Silver brazing rods

PostPosted: Fri Oct 14, 2016 11:01 pm
by coffe addict
On the whole flux isn't needed just heat to red and allow to cool to black. Then braze away. I've found flux handy when you can't get the heat at the right place (ie something in the way) a little flux can help get a good flow of of brazing rod into the hard to get places.

So I would go for unfluxed rods and a small pot of flux.
I'm still a novice though so hopefully someone more experienced will chime in.

Re: Silver brazing rods

PostPosted: Sat Oct 15, 2016 6:20 am
by rumdidlydum
I found the fluxed ones a pain in the arse, unfluxed for me. :D

Re: Silver brazing rods

PostPosted: Sat Oct 15, 2016 10:26 am
by Carbonator
Unfluxed and the higher the Silver content (more expensive) the better the flow into the joint, therefor, easier for a beginner. Copper to copper, just get both cherry red and remove flame and hit it with the solder. If copper to brass or brass to brass, I found the flux paste a must have.

Re: Silver brazing rods

PostPosted: Wed Sep 06, 2017 5:39 pm
by Diggermandan
So 15% are the way to go ??

Re: Silver brazing rods

PostPosted: Wed Sep 06, 2017 6:18 pm
by hillzabilly
Tryed a few now only use boc 45t https://www.boc.com.au/shop/en/au/boc-s ... taf4550t-p ,fluxed rods,does copper ta copper copper ta stainless and stainless ta stainless very well in my opinion,have used other fluxed rods but they come a very shabby second place to the boc ones.cheers hillzabilly ;-)

Re: Silver brazing rods

PostPosted: Wed Sep 06, 2017 7:29 pm
by Diggermandan
Awesome thanx I'll get those ones from boc

Re: Silver brazing rods

PostPosted: Wed Sep 06, 2017 7:57 pm
by hillzabilly
What ever you use make sure all joins a super clean befor ya start the torch,I allways use a bit off emery paper to clean and slightly roughen the area,then wipe down with metho and go for it with a soft slightly oxidizeing flame(the blue cone just after the end of the tip should not be to small but longer with a slightly feathered edge) took me a shit load of practice to get confident so go slow and gentle,with stainless if you overheat it will oxidise and the brazeing will not stick then you will have ta sand it to fresh metal and try again,so only use enough heat ta get the braze ta run .cheers hillzabilly :handgestures-thumbupleft:

Re: Silver brazing rods

PostPosted: Thu Sep 07, 2017 5:05 pm
by ThePaterPiper
hillzabilly wrote:What ever you use make sure all joins a super clean befor ya start the torch,I allways use a bit off emery paper to clean and slightly roughen the area,then wipe down with metho and go for it with a soft slightly oxidizeing flame(the blue cone just after the end of the tip should not be to small but longer with a slightly feathered edge) took me a shit load of practice to get confident so go slow and gentle,with stainless if you overheat it will oxidise and the brazeing will not stick then you will have ta sand it to fresh metal and try again,so only use enough heat ta get the braze ta run .cheers hillzabilly :handgestures-thumbupleft:



Is that with Mapp gas Hillzabilly?

Re: Silver brazing rods

PostPosted: Thu Sep 07, 2017 5:46 pm
by Lowie
ThePaterPiper wrote:
hillzabilly wrote:What ever you use make sure all joins a super clean befor ya start the torch,I allways use a bit off emery paper to clean and slightly roughen the area,then wipe down with metho and go for it with a soft slightly oxidizeing flame(the blue cone just after the end of the tip should not be to small but longer with a slightly feathered edge) took me a shit load of practice to get confident so go slow and gentle,with stainless if you overheat it will oxidise and the brazeing will not stick then you will have ta sand it to fresh metal and try again,so only use enough heat ta get the braze ta run .cheers hillzabilly :handgestures-thumbupleft:



Is that with Mapp gas Hillzabilly?


He's talking about an oxy set mate. You can use Mapp on copper and s/s but I found Mapp took forever to heat a 4" copper pipe for silver soldering. Anything under that no problems with Mapp. Some guys use a torch kit attached to their BBQ bottle which they reckon works ok too.

Re: Silver brazing rods

PostPosted: Thu Sep 07, 2017 6:52 pm
by hillzabilly
Yeh oxy acetalene set mate ,have been able ta get away with mapp on very small jobs but it was a struggle,the benefit of high silver content is a lower melting point and a good free flow without it going crusty like low silver rods,wich can crack and cause havoc with leaks on cooldown,donot quench in water after brazeing just let it cool very slowly .cheers hillzabilly ;-)

Re: Silver brazing rods

PostPosted: Thu Sep 07, 2017 8:29 pm
by bluc
I have been wondering about that hilzabilly. I always thought higher silver was higher melting point..

Re: Silver brazing rods

PostPosted: Fri Sep 08, 2017 4:37 pm
by ThePaterPiper
It's a pain in the arse, but you can gradually cool the joint by applying heat periodically as it cools to slow the cooling process down if using mapp

Re: Silver brazing rods

PostPosted: Sat Sep 09, 2017 8:04 am
by scythe
I kept getting cracking on my RC before i re-did it recently.
Mainly from the small contact area between end plate and vapour tube but also due to cooling down too quickly, vapour tube would cool much faster than the rest of it.

Re: Silver brazing rods

PostPosted: Mon Sep 11, 2017 10:52 am
by warramungas
bluc wrote:I have been wondering about that hilzabilly. I always thought higher silver was higher melting point..


Not in my experience. The other way around.

Re: Silver brazing rods

PostPosted: Wed Sep 13, 2017 4:54 pm
by Sam.
I was under the impression the higher the silver content the better it flows into the joint and why they are more expensive :-B

Re: Silver brazing rods

PostPosted: Wed Sep 13, 2017 6:58 pm
by P3T3rPan
Sam. wrote:I was under the impression the higher the silver content the better it flows into the joint and why they are more expensive :-B

Yah . But at a lower temp as well. Which is why it is so useful when doing a compound join such as a condenser end.

Re: Silver brazing rods

PostPosted: Thu Sep 14, 2017 3:04 pm
by YarraRanges
I use LP gas with oxygen for brazing stainless to copper. I've found that 45% silver works well for brazing stainless ferrules to copper. To do this you must use Tenacity No.6 flux. It can be bought on order from Blackwoods or BOC for around $80.
Tri-clamps are made from Austenitic stainless steel. Austenitic stainless steels are non-magnetic. The Austenitic steels are based on the 18% chromium 8% nickel composition although the chromium addition can vary from 15-22% and the nickel from 6-11%. Austenitic steels if heated between 55O °C and 750 °C will precipitate complex Chromium Carbide which makes standard fluxes useless and the silver braze won't stick. Tenacity No.6 can cope with this.
The only problem is that you need caustic soda or mechanical means to remove the residue after it has cooled.

Re: Silver brazing rods

PostPosted: Thu Sep 14, 2017 8:41 pm
by Sam.
YarraRanges wrote:I use LP gas with oxygen for brazing stainless to copper. I've found that 45% silver works well for brazing stainless ferrules to copper. To do this you must use Tenacity No.6 flux. It can be bought on order from Blackwoods or BOC for around $80.
Tri-clamps are made from Austenitic stainless steel. Austenitic stainless steels are non-magnetic. The Austenitic steels are based on the 18% chromium 8% nickel composition although the chromium addition can vary from 15-22% and the nickel from 6-11%. Austenitic steels if heated between 55O °C and 750 °C will precipitate complex Chromium Carbide which makes standard fluxes useless and the silver braze won't stick. Tenacity No.6 can cope with this.
The only problem is that you need caustic soda or mechanical means to remove the residue after it has cooled.


Firstly a post in the welcome section would be awesome :handgestures-thumbupleft:

Secondly, are you saying Austenitic as a fancy version of 300 series grade stainless? :think:

Wouldn't build a still out of anything less than 304 personally ;-)

Re: Silver brazing rods

PostPosted: Fri Sep 15, 2017 12:54 pm
by YarraRanges
Sam. wrote:
Firstly a post in the welcome section would be awesome :handgestures-thumbupleft:

Secondly, are you saying Austenitic as a fancy version of 300 series grade stainless? :think:

Wouldn't build a still out of anything less than 304 personally ;-)


There are 2 main types of structure in SS. Austenitic and Martensitic, it depends on the tempering process when it is made.

I was talking about brazing SS ferrules to copper tubes. I'm fairly sure that they are 304 and are definitely Austenitic as the Chromium Carbide certainly clogs up conventional flux. Since using Tenacity No.6 flux I've had no problems brazing stainless to stainless and copper to stainless. $80 for a small pot seems expensive but I've been using it for years. It goes a long way.
I'm now off to the welcome section. :)