On Fri, 11 Jun 2010 03:59:19 +0100, Ted Frater
wrote:

Wes wrote:
"Artemus" wrote:

Obviously I'm doing something wrong here as my joints are brittle
and don't hold worth squat. I ground the ends of the blade to about
45 degrees and cleaned the ends with sandpaper. I put on plenty
of flux and wedged a small piece of silver solder in the scarf joint.


Silver solder (low silver content) or silver braze (high silver content)?

Wes
--
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller


Ill come in here,
Ive silver brazed my band saw lades for 40 yrs.
as linked, the scarf joint needs to be minimum 3/8ths in long, you do
this scarfing on the top wheel of a band sander set up vertically.
Jig as also described, but bend the lower blade end up a little and he
top blade down a little.
You need to use a 50% if you can get it silver solder in foil form, 5
to 10/1000 in thick. cut a piece exactly to size, place between the 2
blade ends. mx up some easyflo flux paste preferrably s/steel grade,
apply arround the joint area. heat gently till the flux goes clear,
continue to heat till the joint goes a dull red under the flux and the
silver solder flows to wet the scarf area. allow to cool clowly.
Remove from jig, fftle up and grind both sides of blade so that the
thickness is the same overall, as you said .025 thick.
dont over tension the saw blade.
Hope this helps.
Ted. Dorset UK.

I've also silver brazed my blades for many years but slightly
differently.

The 30 deg bevelled blades are held in a simple open jig with
small G clamps.

An 0.005" feeler gauge (subsequently withdrawn) spaces the two
ends to provide a proper capillary gap.

The gap is covered with a thick wodge of flux. A very short
snippet of silver solder wire is embedded within this flux - only
enough solder volume to slightly overfill the 0.005" nominal
gap

With the blade horizontal (flux + solder on top) the UNDERSIDE
is heated with a propane or MAPP gas torch. This gives complete
visual control of the heating process without danger of under or
overheating. As the temperature rises the flux, while still
covering the solder, melts and becomes transparent. You can then
observe the exact moment when the solder melts and flashes into
the joint.

This consistently produces clean reliable joints which require
little or no dressing after brazing.

Jim