The Shop > Metal Stuff
First time brass brazing
JHovel:
Hi Surfdabbler,
I think its been well covered already. But to emphasize a couple of points: the 5% siver solder is for plumbing fittings which have a large surface area in their sockets on corresponding pipes. For small surface areas like yours, I would not try it. 45% silver or the Phoson (I have no idea where to get that in Australia though, try BOC for either.) is the stuff to use. By the way, they are the fillers used to braze tungsten carbide onto tools.
Your flux should be OK. In fact clean brass and copper will siver solder/braze without flux. Steel won't. If your flux is runny, then the borax has settle out. Scrape the bottom of the container and mix it back into the liquid.
Lastly, I have a suspicion your not getting the joint hot enough. THe flux will 'run everywhere' when up to brazing temperature - and the silver will run towards the heat. Beading of your flux is a sign on not quite enough heat. Incidentally, the silver solder you used should run 'like water' not make fillets or leave lumps at the right temperature. Did it?
mattinker:
--- Quote from: JHovel on April 03, 2016, 10:46:28 AM --- 45% silver or the Phoson (I have no idea where to get that in Australia though, try BOC for either.) is the stuff to use. By the way, they are the fillers used to braze tungsten carbide onto tools.
--- End quote ---
Just a tiny hi-jack!
Hovel,
That's interesting, I didn't know that Phoson was used for brazing carbide tooling, I've got lots of it from plumbing, cheaper than silver solder!
Thanks again, regards, Matthew
DavidA:
Surfdabbler,
Probably a silly question, but are you sure that it is brass ? And not something like ally-bronze.
I was caught out by this years ago.
Dave.
surfdabbler:
Wow, thanks for all the replies. Awemawson, you have pretty much done what I am trying to do. The head of your bolt is slightly thicker - I think mine is 1/8", or about 3mm thick. I think I have to track down a couple of firebricks to work on too, or make up a sand/kitty litter tray. Your balancing trick looked clever - I have something like this that I can set up to help balance during brazing.
To answer various other points raised...
- Yes, I'm sure it's brass - bought new from a reputable brass supplier the other day.
- I was wondering about the silver content. The high silver content rods are pretty expensive, but I might have to shell out for some if this doesn't work.
- My brass is not getting glowing hot at all. I was taking it just far enough to melt the brazing rod, but perhaps I should take it further. It's an old torch, so I might need to insulate around the workpiece to get it hot enough.
- I had assumed that a butt joint would be fine, but I can try a dimple
Will try some more soon, and take some pics...
awemawson:
Happy to post you a Phoson rod if you like. It'll cut up into envelope lengthed bits so shouldn't be too pricey.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version