Thread: Silver Solder or Braze

Originally Posted by d2dave

On my D2 transmission cooling lines I am cutting off the rubber hose and will be attaching a weld on AN fitting.

What is better, silver solder or brazing/bronze weld?

TIG

Braze it. when I put Power steering on my Power Wagon I went to the local hydraulics place for a suitable adapter , He did not have any crimp connectors to suit but sold me a weld on fitting , asked the same question , Answer a strong Braze it . Job done took 3 minutes , would not even bother setting up the Tig for that.

Technically, silver soldering is brazing. You're using well over 600* to get the braze rod to melt.
As it's steel you'd be using 45% silver at a minimum, and you'll need a good silver brazing flux.
This is bloody strong, and if done properly, unbelievably neat.
I'd have no issue using 45% silver brazing alloy, in fact, that's how i'd do it, and it'll cope with pressures far above anything the AT will throw at it.
In my line of work it's routinely used on CO2 systems seeing up to 90bar, and safety rated to 120bar. (1750psi)

Another couple of notes on silver brazing.

Custom, lugged steel bike frames are silver brazed, the ones using really exxy Reynolds or Columbus steel, so it's strong.

And a little vanity, this is a braze joint on a $1000+ electronic expansion valve, admittedly not steel, but stainless steel to copper using 45% silver rod. Stainless can be nasty if you overheat it, even just slightly. I wasn't going for super flash, this was a field repair and I was going for quick as I didn't want the system open for too long but you can be quick and neat when you have your flame and heat right.
IIRC it was either 1,3/8" or 1,5/8" tube?

I took a photo to send to all our techs to show that a) the old bloke can braze and b) this is the standard I expect from them all
Scarry can confirm that a lot of tradesman's brazing these days looks like bird poo.

braze joint.jpg

Originally Posted by rick130

Scarry can confirm that a lot of tradesman's brazing these days looks like bird poo.

braze joint.jpg

That is a nice braze,done heaps over the years on service valves.

The bird poo brazes,yes they often leak as well,not enough penetration,too much or not enough heat.Or they use Brown tip where they should be using blue,45%,as it is cheaper....

The other thing with 45% silver solder,the materials have to be perfectly clean,this is very important.And as Rick said,get the steel too hot,which is very easy to do,and it is all over,the solder probably won't take.

Originally Posted by rick130

Technically, silver soldering is brazing. You're using well over 600* to get the braze rod to melt.
As it's steel you'd be using 45% silver at a minimum, and you'll need a good silver brazing flux.
This is bloody strong, and if done properly, unbelievably neat.
I'd have no issue using 45% silver brazing alloy, in fact, that's how i'd do it, and it'll cope with pressures far above anything the AT will throw at it.
In my line of work it's routinely used on CO2 systems seeing up to 90bar, and safety rated to 120bar. (1750psi)

Thanks Rick. When starting this thread I was hoping to hear from you as I thought this would be up your alley.

I have a couple of questions. After some research, I did come to the conclusion that brazing and silver soldering are both brazing.

However, growing up I always thought silver soldering was using a stick with silver and brazing was using brass colored rods and a different flux to silver solder.

You can also get bronze rods coated with flux. So my question here is, what is the correct terminology to define the two different methods?

Next question. Why 45% silver. My research tells me that higher silver just means lower temps needed for doing the job.

I have stacks of lower stuff in my shed. 3 or 5% from memory. Same stuff plumbers use. If you can tell me why I need 45% for this job I am happy to go and get 45%, providing I can buy one or two and not a pack,

as I guess I would have to sell a kidney to get a pack. (and buying landrover parts I am running out of kidneys)

Also is the flux I have ok for this job?Silver solder.jpg

The pics say brazed but I'm sure I silver soldered mine. (the pics are named "silver-solder-braze-oil_cooler_lines".)


Oil_cooler_lines_-2.JPG

Oil_cooler_lines-8w.jpg

Originally Posted by goingbush

would not even bother setting up the Tig for that.

Yeah, well.... Pirtek did mine.