[BC] brazing

[Cowboy]

On Friday 20 May 2005 21:51, Milton R. Holladay Jr. wrote:
> 15%,10%, 7%, 5%, or even 0% silver, Sta-silv, Sil-phos, or whatever other
> name it may go by, the flattened rods used by AC techs and plumbers, all
> work fine, no flux required or needed, as long as there is no encrusted
> stuff on the copper; a carburizing flame will remove the
> tarnish.............

 I've found that flux is needed in only very, very few cases.
 ( or a wire brush. If the material is clean, the just go with it.
 If not, CLEAN it first )

> The toughest thing that I've attached to is galvanized steel. Usually, it
> works to use a BIG torch and flow some brass rod onto/into the surface and
> silver solder the copper to that..........

 Galvanized is no different that raw steel, but first remove the galv !
 Just can't braze anything to a galv coating.
 
 Generally, I'll heat the intended braze track of the galv, then wire brush.
 Usually, the galv comes off where heated almost allways.
 If not, re-heat that strip, and brush again.
 Then, tin the raw steel with whatever rod you're using.
 Finally, lay in the copper, and make the final braze.

 Then, of course, cold-galv the joint, lest the steel rust where the galv
 has been removed.