AussieDistiller1989 wrote:Thank you that's a good tip.
What's the other thing apart from lead I don't want in my flux
And rods
Most brazing fluxes remain on the surface where you can chip or wash them off.
Silver brazing alloys (silfos for instance) usually are food grade.
The higher the silver content the easier it is to use. The 15% (silfos) stuff is what plumbers use the most on water supply. The lower grade (silbralloy) is used on waste pipes and the higher grade (easyflow) is used to join dissimilar metals (ss for instance) to copper.
Dominator got it right re using the heat to control where the silver brazing alloy goes.
Joint preparation also allows you to control where the silfos (or whatever the silver brazing alloy is called) will go. This can be used to advantage on more difficult joins.
It is important to realize that the strength of any join is in the surface area joined, not in how thick you apply the filler rod, whether it be soft soldering (solder, lead solder), brazing (silfos,bronze etc) or welding in all its forms.
When brazing old dirty copper, bring it to a cherry red then quench it in cold water. This will bring the oxides and filth to the surface to flake off. Prep your join with emery cloth and go for it.
Silfos has a proprietary flux but it is only needed when brazing filthy copper or brazing copper to brass.
Most times I don't bother with the quenching or the prepping or the flux, but i have been doing it for 46 years, just wait a second or two with the gas off the heated work and it will go from cherry red to black and shed the oxides, then straight back to brazing, with little loss of heat.
Brazing copper with silfos is easy, fast, very strong, very controllable, and fun. (Some will say that it is expensive but for me time is money and soldering is too slow and too weak and too prone to leaking for the pressures in town water supplies and at the bottom of tall waste stacks, and usually involves corrosive fluxes that end up on the clients carpet or my skin)
Find some test bits and have a go.
Use a 'soft' (almost carburizing) flame. Keep your flame moving.
Heat the work,not the rod.
When the work is the right temp the rod will melt on contact with it.
Concentrate your heat on the thickest part of your work and watch the rod suck into the join.
While simple straight socket joins and lap joins can be done with air-fuel gas very successfully, oxy-fuel gas (especially acetylene) makes multiple close together joins and joins in larger diameters much easier.
Sent from my iPhone 4s using Tapatalk
Sent from my iPhone 4s using Tapatalk