Brian- I have never used powdered flux. Tell me more, please.......... Deb
Sure, Deb.
It’s a standard flux with plumbers and brazers using what we
call here Eziflo for sil-phos, or a silver-bearing brazing rod.
There are other brands like Kendall, Harris. Johnson Matthey, UK
precious metals co, recommend an Eziflo flux for their golds and
silvers, well they did last time I looked at their info sheet
back in 1980something.
If you’ve seen anyone braze, like a plumber or a steel worker,
you’ll probably have seen them dip the brazing rod right into the
powder flux and it comes out coated and ready to apply to the hot
metal. This is what I do with strips of silver solder snipped off
the sheet. If I use solder paillons I apply them via the
soldering pick onto the pre-fluxed work.
There are great advances made in flux technology, and many
different fluxes available outside the jewelery suppliers that
are great fluxes. Choose them for their WORKING TEMPERATURE
RANGE. Many come in either powder or paste form. I have one I use
for mild steel - silver soldering it to silver or gold. And
another super-high-temp flux, Stay-Silv, for stainless steel,-
the flux stays active up to 1000=B0C (1832=B0F).
I prefer the powder form over paste. Paste always requires an
extra step of drying the water out of it. And this makes the
solder bits jump around, and if you add it during a soldering job
it cools the work down somewhat.
I apply flux to the work with a solder-pick - I WARM the work,
apply the flux, and heat the work up. When the flux turns glassy
and the temp look right, I introduce the (flux-coated) solder
stick. If the solder doesn’t run immediately, I withdraw it and
heat it up higher. If the flux gets depleted arounfd the joint, I
get the pick and coat it with dry flux (periferal vision hightly
developed! as I don’t want to take the flame of the work), and
add more flux.
Bring in the solder again, and if the work’s at the right temp
it flows towards the hottest area, usually flameward.
I know stick soldering allows for dumping far too much solder
into a joint, but if I’m careful I can limit how much I use.
Otherwise as I say, I use paillons - pick one up with a warmed
pick and apply it when the job’s halfway heated, jiggle it til
it’s in the perfect place, and when it is, heat right up to
soldering temp. I’m a flux fiend, so a little prolonged heating
at say 400-500=B0C doesn’t do any damage. However I try to keep the
time at soldering temp (700-170=B0C) as short as possible, as this
is where oxidation and firescale develops.
I’ve seen students holding work at high heat for WAY too long -
the flux (borax) burns off and the oxides get deep into the
surface. Plus the solder joint if it happened at all is a poor
one.
A word of warning. As I’m sure many on this list will attest,
these fluxes require good ventilation when working with them.
Some of the components in Eziflo fluxes carry strong respiratory
warnings. Plus powders of any sort require the handling
precaution that you don’t stir them up unecessarily and inhale
the dust.
Has this helped?
Brian
B r i a n =A0 A d a m J e w e l l e r y E y e w e a r =A0
@Brian_Adam1 ph/fx +64 9 817 6816 NEW ZEALAND
Brian Adam Eyewear artworks - spectacles
Brian Adam Jewellery earrings rings NZ jade
http://www.adam.co.nz/workshop/ NEXT: Queenstown NZ Jan 13 1998
http://www.adam.co.nz/ruthbaird/ Ruth makes her jewellery alongside me