That sounds similar to prips flux but minus the trisodium
phosphate and using alcohol instead of water. I currently use boric
acid in alcohol. Would adding borax (which I also have) improve my
flux's anti-firestain properties?
Boric acid and borax are very similar in the way they protect the
metal. The big difference between them is that borax melts and starts
to become an active flux at a lower temperature, and burns away as
well, more quickly. The boric acid doesn’t become fully active until
a higher temperature, and it lasts longer and withstands that higher
temperature too. So the combination ends up being a bit more
versatile, starting to protect earlier in the process, and
continueing to do so the same as boric acid alone would do.
The sodium phosphate in Prips doesn’t affect the performance of the
flux in it’s protection abilities, but rather, affects the way it’s
applied and how it initially behaves as you heat up the metal.
Without it, surface tension causes the as-yet unmelted flux coating
to start to melt, but not stick to the metal so well, so it balls up
or pulls away from areas. Sometimes the effect will be a mostly
coated piece of metal with lots of small unprotected little islands.
The metal ends up with fire stain in sort of a leopard’s spots
Even with the sodium phosphate, if the prips flux coating is too
thick or uneven in application, the thicker areas will still tend to
pull away. This happens as well if the metal is dirty or greasy or
something. The reason why it’s normally best applied with a sprayer,
rather than a brush, is that getting a uniform light white crust of
even thickness is much easier. With a brush, one tends to chill the
metal enough so some of the flux goes on wet, then boils. That leads
to uneven little “bubble” like areas with a thicker ring of flux
surrounding a mostly bare little area. Spraying, and keeping the
metal hot enough so the flux dries instantly on contact without a wet
looking stage, gives one the uniform coating needed. The fairly new
commercial product, “Firescoff”, also want’s to be applied in the
The need for some sort of a surfactant added to the classic boric
acid used to protect gold, prompted another "kitchen chemistry"
product also worth mentioning. At some point (in the 60s) after John
Prip formulated and taught the use of prips flux to prevent fire
scale and fire stain, the Richard Thomas, then head of the
jewelry/metals department at Cranbrook Acadamy of Art just outside
Detroit, started playing around a bit. He wanted a product that would
protect against fire stain and fire scale as does prips, but without
needing that sprayed application, which does sort of waste some flux,
and can make a bit of a mess of one’s soldering pad what with
overspray. A dipped or brushed on product would be much easier to
use. He’d seen a photo, I think in Life Magazine of a pond in which
ducks were swimming. As they approached one end of the pond, to
which a new industrial surfactant had been added, they swam lower and
lower until just their necks were out of the water, kind of like
submarines going under… The surfactant was allowing the water to
wet the bird’s feathers, so they lost their water proofing, and with
it, their boyancy. Made for a dramatic photo illustrating how good a
wetting agent the stuff was. So Richard did some experimenting of his
own with the stuff, called “Aerosol OT-solid”, If I remember it
right. Not a grocery store item, one gets it from the manufacturers
as a somewhat waxy looking solid that can take a bit of doing to get
fully dissolved. But Richard found that a mix of this stuff, with
just plain boric acid and water, gave just the protection he wanted
againts fire scale and fire stain. In honor of the light bulb or bell
or whatever that had gone off in his head when he’s seen that photo
and thought to try and produce a protectant with it, he named this
formula “Ring-a-ding” Kind of an in joke, and testament to Richard’s
wry sense of humor. As a fire stain and fire scale protectant on
sterling, it’s very effective, though the end surface after pickling
is not quite as bright as it can be with prips. But it’s simply
brushed on the surface or dipped. Much quicker than spraying prips.
Unfortunately, there’s a bit down side. The surfactant apparently
also acts in other ways, with the result that the mix is almost an
anti flux for soldering purposes. If you are very careful to paint
it on only an areas which are not being soldered, and use soldering
flux for the seams, you can protect work being soldered. But that’s
difficult, and prips works easier when doing any soldering.
Ring-a-ding ends up being wonderful for annealing, but not much help
in soldering. Given that Cranbrook then emphasized a great deal of
hollow ware work, people were doing a lot of annealing of their
silver between courses of hammer work, so this mix was very much
useful and a time saver. The recipe and instructions for mixing it up
were published at least once in Metalsmith, and for a time, C.R.Hill
co near Detroit, was carrying the stuff. But they tended to mix it
way too dilute, according to Richard. I’ve seen it used at only one
other school, Tyler School of art, where I did my MFA work. There,
though it was available, most students didn’t know about it or bother
with it if they did. A bit too bad, since it really is useful for
annealing processes, even if it’s not good for soldering operations.
The other interesting variant on all this was, I’m told, started
when the purchase of TSP for use in making up prips flux because more
difficult. It used to be available in any paint store or the painting
aisle in the hardware store. Then it’s use became discouraged because
its a phosphate, and in waste water, ends up being a wonderful
fertilizer for algae and other undesired plant life in the water
streams, so phosphates in detergents in general became regulated.
Since then, finding TSP has often prooved to be a bit of a fuss and
bother, and in some areas, almost impossible to find outside of
ordering from a chemical’s supplier at higher cost.
So again, a bit of kitchen chemistry raised it’s head. In this case,
it was by Fred Fenster, who’s the teacher who first taught me about
prips flux in 72. Fred figured that there must be other products out
there, easily and cheaply available, that would work as well as the
pure TSP. He ended up with Cascade dish washing powdered cleaner.
Comes in a nice bright green box, and will get your dishes clean and
spot free and all that jazz. Apparently, it’s mostly TSP, with no
doubt some other surfactants and wetting agents and whatever. It can
be substituted directly for the TSP in the prips formula. Fred named
his variant “Frips flux”.
So now you’ve got the whole story as far as I know it, and my
fingers have had their workout for tonight.