RECIPE FROM THE COMPLETE METALSMITH
2 fluid oz borax
2 fluid oz tri-sodium phosphate (TSP)
3 fluid oz boric acid.
Fluid ounces for dry powdered ingredients? That seems odd to me. If
it seems odd to you too, try 64 grams of each of the first two, and
96 grams of the boric acid. Also in a quart of water. Tap water is
fine. This makes a pretty saturated solution. You can dilute it a bit
more if you like, but then you just have to spray more on. If, after
dissolving it in boiling water, and on cooling, some crystalizes out
again, just add a bit more water to fully dissolve
Boil the above ingredients in 1 quart water. Longer boiling makes
it better.
Unless you mean by making sure it’s all dissolved, I can’t imagine
why boiling it longer would do anything at all. This isn’t ministrone
soup. The ingredients simply need to dissolve, not cook.
The stuff is used by putting it in a spray bottle.
Yes, but most spray bottles use a tiny hole as a spray orifice,
which quickly clogs as flux dries on it between uses. And many spray
bottles don’t give an especially even spray pattern. More effective
are “venturi” type sprayers. These include external mix air brushes,
or the simple “two tube on a hinge” type mouth blown atomizer
sprayers sold in ceramics supply shops to spray glazes. Some folks
have had good results with the type of sprayer/atomizer used for
asthma inhalers, stored with the nozzle under water when not in use
to prevent clogging.
Heat the work but not enough to cause discoloration. Spray the flux
on the part and it will dry. Do this a few times till an unbroken
coat forms.
It needs to dry on contact, not go on wet and then dry. if it does
that, the coating won’t be uniform in thickness, and will tend not to
fully adhere, with more thickly applied areas tending to pull away
from the thinner areas, leaving some bare patches. If this happens as
you heat the metal, just spray a little more to cover the bald spots.
Apparently it is THE best flux for preventing firestain. There are
products such as Firescoff but they cost quite a lot for a little
spray bottle so it's much cheaper to buy the chemicals and make
your own Prips flux. The chemicals will last for a good while and
are readily available - at least they are in the UK.
In my brief tests with it, I found Firescoff to be perhaps slightly
more effective, in that it seems to resist overheating even better
than prips (already good). So it’s a bit more robust in that sense.
And the included spray bottle avoids needing to find something that
will work. But as Helen points out, the stuff is for wealthy jewelers
only, given it’s rather high price. I liked it, but am not, given
it’s cost, at all tempted to switch from Prips. Especially since I
still have a quart of the prips sitting here, and enough chemical to
make several more gallons…
Apparently (and someone else may care to elaborate), borax can be
bought in the form of roach killer
No. Boric acid is sometimes sold as a roach killer. Borax is sold in
the laundry aisle at the grocers. In the U.S., the brand most
commonly seen is Borateem. I’ve also seen it sold as just plain
generic laundry borax.
and TSP is also sold as some sort of household product (can't
remember what for) and any extra ingredients don't impede the
flux's functionality.
In the U.S., at least, Cascade dishwashing machine powdered
detergent is, I think, mostly TSP. Even if that’s not totally true,
it can be used as a substitute. Some reports say it works even better
than plain TSP. I don’t know, not having tried it yet.
Peter