Page 3 of 4

Re: Hard soldering. Brazing. Silver.

PostPosted: Mon Sep 05, 2016 10:46 am
by WTDist
lol, i will go there and get them in my high vis too then :))
even though i dont work anymore :))

thats a good price

Re: Hard soldering. Brazing. Silver.

PostPosted: Mon Sep 05, 2016 11:05 am
by P3T3rPan
WTDist wrote:Couple of questions though,

when brazing does it help to clean the joints with some sand paper or something like with soft solder?
Copper self cleans when up to dull red then left for a couple of moments to go black(cool). Only the worst lead based paint can be difficult but I guess you wont be using that shit. Some "sandpapers" leave shit on the join area causing grieff

and i know people say you dont need flux with copper to copper and i did not use any this time or when i do flange rings but is there any benefit for it with flux on copper to make it a little easier or is it just a waste of time and money?
I do this for a living and only use flux when brazing dissimilar metals (brass to copper etc) cos it is a waste of money and flux deposits cause corrosion in the long term and/or hide defects in the short term

and lastly i used 2% a while ago on rings for flanges and switched to 5% (used this today also) and saw a msssive difference in how easy it was to use compared to the 2% on the swivel map gas torch. Does the silver % matter just as much now i have the oxy/map kit with the high heat?

The higher the silver the less heat is needed. This can be exploited when doing lots of joins in close proximity. For example shotgun condensers
Your best friend when doing pretty joins is whiteout
After many years soldering stuff as an apprentice we started brazing using silver alloys and threw all our problems away with the soldering gear

Re: Hard soldering. Brazing. Silver.

PostPosted: Mon Sep 05, 2016 11:26 am
by WTDist
cheers p3t3r, that helps alot

Re: Hard soldering. Brazing. Silver.

PostPosted: Mon Sep 05, 2016 11:27 am
by P3T3rPan
goes black
IMG_3287.JPG

White out
IMG_3286.JPG

no flux (No cleanup done on this)
IMG_3299 (640x480).jpg

Re: Hard soldering. Brazing. Silver.

PostPosted: Thu Nov 30, 2017 4:30 pm
by bluc
So for silver soldering(not soft solder) what flux do i need for copper to stainless?

Re: Hard soldering. Brazing. Silver.

PostPosted: Thu Nov 30, 2017 6:16 pm
by bluc
So after spending last 2ish hours on the topic I have bought some stay silv by harris. Good for high temp silver soldering stainless to copper :handgestures-thumbupleft:

Re: Hard soldering. Brazing. Silver.

PostPosted: Thu Nov 30, 2017 7:01 pm
by P3T3rPan
bluc wrote:So for silver soldering(not soft solder) what flux do i need for copper to stainless?

Well I used this cos that is what I have and am used to.
flux.JPG

Now i use this. :cool:
TIG.JPG

Re: Hard soldering. Brazing. Silver.

PostPosted: Mon Feb 25, 2019 6:23 pm
by scottyd72
This looks like the place to ask about brazing or silver soldering 2 pieces of brass together. I’m making my own custom hose fittings for my bubbler build and the 2.5% flows but only on one side. I’m also using bakers soldering flux. I think I have it all wrong, so can someone tell me what solder and flux I should be using pls?

Re: Hard soldering. Brazing. Silver.

PostPosted: Tue Feb 26, 2019 12:06 pm
by YarraRanges
bluc wrote:So for silver soldering(not soft solder) what flux do i need for copper to stainless?

I got this from a friend who built his still using copper tubes and stainless ferrules.

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%. These steels cannot be hardened by heat treatment and must rely for their
mechanical properties on mechanical working. This means that any thermal joining treatment will reduce the
mechanical properties in the 'heat affected zone'.
Austenitic steels if heated between 55O °C and 750 °C will precipitate complex Chromium Carbide. This will render the
material susceptible to a rapid corrosion process known as weld decay. The degree of this precipitation will be a function
of the carbon content but it is obvious that most thermal joining processes will be a potential hazard. The steels can be
stabilised by the addition of either niobium or titanium and all Austenitic steels that are to be brazed or welded should
either be in this condition or have a low carbon content. (302, 303, 304, 310, 316, 321, 325 and 347).
Fluxes
The use of a flux is essential when brazing stainless steel in air. With components where the joint area can be easily
heated up to brazing temperature, Easyflo flux can be used. However, should prolonged heating be necessary, a flux
metal reaction will take place when this flux is used. This reaction will form a film on the surface of the stainless steel so
that it cannot be 'wetted' by the brazing alloy, and the addition of fresh flux will not remove this film. In these instances
it is necessary to use Tenacity Flux No 6 flux. This has improved high temperature properties and does not react with
stainless steel. The only problem is that the residues are not water-soluble and have to be removed with caustic soda, or
mechanical methods, such as grit blasting.
Tenacity flux can be bought from BOC but they have to get it in. They don't have it on their shelves.

Re: Hard soldering. Brazing. Silver.

PostPosted: Tue Feb 26, 2019 1:02 pm
by hillzabilly
Boc t45 silver brazeing rods come coated with flux.Will do copper-copper,copper-SS,brass-brass.Its all I use flows well without the crusty look after too.Not cheap but work very well.This bit has SS copper and brass done with the t45 rods.cheers hillzabilly ;-)

Re: Hard soldering. Brazing. Silver.

PostPosted: Tue Feb 26, 2019 1:30 pm
by bluc
Very nice hilzabilly :clap: and thanks for the info :handgestures-thumbupleft:

Re: Hard soldering. Brazing. Silver.

PostPosted: Tue Feb 26, 2019 3:00 pm
by YarraRanges
hillzabilly wrote:Boc t45 silver brazeing rods come coated with flux.Will do copper-copper,copper-SS,brass-brass.Its all I use flows well without the crusty look after too.Not cheap but work very well.This bit has SS copper and brass done with the t45 rods.cheers hillzabilly ;-)


Wow! That looks nice. How hard is it to clean up the flux hillzabilly?

Re: Hard soldering. Brazing. Silver.

PostPosted: Tue Feb 26, 2019 7:21 pm
by hillzabilly
No different to any of the others,citric bath,scrub with scrubbies another citric bath,then sak run and your away.And it will do stainless to stainless.cheers hillzabilly ;-)

Re: Hard soldering. Brazing. Silver.

PostPosted: Tue Feb 26, 2019 7:55 pm
by bluc
So on subject of brazing in particular ss-ss. I have a 30l keg I would love to braze a 6" ferrule on for access. It has had 65% spirit in it on off for couple years.
I would prefer not to blow myself up and am wondering if this would be safe to braze?(hard solder).
I know they fill fuel tanks up with water but I doubt I could get it hot enough while full of water to hard solder..

Re: Hard soldering. Brazing. Silver.

PostPosted: Wed Feb 27, 2019 3:00 pm
by scythe
Fill it with water to the brim then empty it.
What ever is left will be of such low percentage that it won't matter how hot you get it.

Stainless does not absorb the alcohol and if it does even minutely the water will get sucked in as well and reduce the %ABV of what ever is absorbed.

If your that worried you could drop a handfull of dry ice in the bottom so that it is "purged" with CO2.

Re: Hard soldering. Brazing. Silver.

PostPosted: Wed Feb 27, 2019 8:17 pm
by bluc
Nice idea with dry ice thanks :handgestures-thumbupleft:

Re: Hard soldering. Brazing. Silver.

PostPosted: Fri Mar 01, 2019 6:46 am
by RC Al
Errmmm. Carbon dioxide has 3x the oxygen content of regular atmosphere, it will only contaminate the weld further

Re: Hard soldering. Brazing. Silver.

PostPosted: Fri Mar 01, 2019 7:36 am
by Sam.
RC Al wrote:Errmmm. Carbon dioxide has 3x the oxygen content of regular atmosphere, it will only contaminate the weld further


Then why can’t you breathe it?

Re: Hard soldering. Brazing. Silver.

PostPosted: Fri Mar 01, 2019 2:06 pm
by scythe
The CO2 is there as explosion protection, not weld protection, however CO2 can be used as a sheilding gas in MIG.

Re: Hard soldering. Brazing. Silver.

PostPosted: Fri Mar 01, 2019 5:05 pm
by RC Al
Sam. wrote:
RC Al wrote:Errmmm. Carbon dioxide has 3x the oxygen content of regular atmosphere, it will only contaminate the weld further


Then why can’t you breathe it?


cause your body aint equipped to split the 2 oxygen bits from the carbon bit and then dispose of the carbon bit - like a tree dose

scythe wrote:The CO2 is there as explosion protection, not weld protection, however CO2 can be used as a sheilding gas in MIG.

Ahh fair enough, i see where you were going with that now
You used the purge word, so given the thread title, someone may get the impression that you could weld your keg safely using the dry ice to purge

Co2 is a horrible shielding gas for mig bar a few situations