Brazing Guilding Metal?

[Fhqwhgads6680]

Hey guys I am getting ready to put my order in for my evaporators, and I had a thought that guilding metal ( 90% copper 10% zinc ) would help reduce cost a bit if I used it on the tops since the top doesn't transfer hardly and heat from the processor. My only concern was would this be more difficult to braze and would I be able to use standard 15% sil-fos rods?

thanks,
Brandon J

[Marvin]

it will depend which torch would you use.
oxy/acet works well with phoscooper.

[Unknown_road]

with 15% silfos you don't get very nice joints, using flux helps a bit but still not great. using high silver content rods makes it a lot easier and gives much nicer joints.

[Fhqwhgads6680]

Thanks unknown thats what I wanted to know! Appreciate it!

[Exahertz]

we make our own ultra-high vacuum fittings and feedthroughs at my work. we use a very common high silver and bismuth alloy rod for brazing to stainless, copper, inconel, and titanium. high silver does give for a nice looking braze along with a very good gas leak resistance. we leak check all of our fittings with an inficon residual gas analyzer and helium gas (as helium is a very small atom and can sneak through cracks when all other atoms besides hydrogen cannot). the best i've seen with high silver is a seal to a vacuum level of 10^-10 torr (or 1/10millionths of a micron). thus silver brazing is rated for ultra-high vacuum (and using UHV and helium analyzers is the best leak test method i can think of)

[PhilippF]

When brazing copper to copper, rods with phosporus (and x percent silver) will do fine. When brazing copper to something else, every manufacturer of brazing rods says you have to use additional flux.

You can have a look at the Harris Webpage:

http://www.harrisproductsgroup.com/

So I dont know it it is worth to save a few bucks on copper when you have to give up the nice and easy solf-flowing brazing with SilFos rods...


Regards,

Philipp