I don't have the package in front of me, but I believe it's a
potassium fluoroborate flux. Do you have a recommendation?
This joint was copper tube to the Shapeways bronze/stainless hybrid
printed material. Info and datasheet, if you haven't seen it before:
https://www.shapeways.com/materials/steel
https://static1.sw-cdn.net/files/cms/materials/data-sheets/Steel%20data%20sheet.pdf
It's 60% 420SS sintered powder, infused with 40% bronze (90% Cu / 10% Sn).
There's another joint that's 304SS tubing to the same printed
material. Ideally, I'd like to do all the braze joints at the same
time using the same flux and the same solder wire, so I can keep the
working time short and the brazing operation simple. But if I have to
use different fluxes or whatever I can. For welding, the data sheet
recommends TIG with a silicon bronze rod.
Thanks!
Evan Daniel
On Thu, Aug 8, 2019 at 2:59 PM Peter Fairbrother <peter@xxxxxxxxxx> wrote:
On 08/08/2019 18:19, Evan Daniel wrote:
We used a paste type flux. I applied the flux to all surfaces to be
joined before assembly. The solder appeared to my unpracticed eye to
wick in and around the joint during brazing. On inspection after the
failure, it seemed like I had good wicking action on most of the butt
joint contact area, but not on any of the slip joint area. I have no
good way to inspect the opposite side of the joint after assembly,
since that's inside the tiny chamber.
I added a fourth photo to the gallery, I think it shows that behavior
best. Here it is:
https://imgur.com/PHK2GMp
Yikes, hot. I don't know precisely why, but as you say the slip joint
hasn't wetted.
What flux are you using? You might need a stainless flux.
X-ray vision:
https://www.youtube.com/watch?v=no-OWfC5-RY
Peter Fairbrother
