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Prips flux


I seem to have lost the recipe I downloaded here for prips flux, and
can’t find it in the archives. Could someone please post it again?

Janet Kofoed


G’day Janet; here you go:- Boric acid 90 Grams; Borax 60g; Tri
sodium phosphate 60g; Water 946 mls. You can of course, make up a
smaller amount by proportioning the weights. – John Burgess;
@John_Burgess2 of Mapua Nelson NZ


To make it, mix 120 grams boric acid, 80 grams borax (you can get
borax cheaply in the grocery stores laundry aisle, sold as borateem or
the like. These are sold as detergents, but are almost all borax with
a bit of whitening agents. Those are the little blue crystals, which
don’t hurt the flux at all), and 80 grams TSP (be sure it’s the real
stuff, not a substitute. Must be trisodium phosphate, not some of the
phosphate free cleaners confusingly labled with similar names) into
about a liter of boiling water (tap water is usually fine). dissolve
all. May need a tad more water to keep in solution once cool.

To use, preheat the silver enough with a soft torch flame so that the
flux, when sprayed on with a sprayer, instantly dries on contact,
forming a uniform white crust on the silver. Don’t heat so much that
the silver discolors from the heat. Coat all sides. Put on just
enough so that the reflective surface of the metal is hidden, and all
you see is the flux coat, but not more than that or it can pull back
when you later go to solder, leaving unprotected areas. When you do
go to solder, as you heat it, the frosted surface crust should glaze
over as it melts, leaving a thin transparent coating that protects the
silver from the atmosphere even through fairly prolonged
soldering/heating cycles.

The best sprayers produce a fine uniform spray. Most trigger spray
bottles don’t do that, making it hard to apply, giving you too much in
some areas, not enough in others, or causing puddles, which then form
rings of thick flux with little in the middle when you heat it, and
then don’t glaze over properly, but pull away as you heat. My
favorite sprayers are the cheap little mouth atomizer sprayers sold in
ceramics supply shops for application of ceramics glazes. These are
just two tube mounted to a hinge, one dips in the flux, the other is
shorter and wider in diameter, and lets you blow across the end of
the first. Simple to make if you had to. Some types of perfume spray
bottles work too, as do some of the inhalent/atomizers used for nasal
sprays or asthma inhalers. So does a cheap style of air brush known
as an external mix air brush, which does the same thing as that mouth
atomizer only with a compressor or bottle air supply. Harbor freight
sells a cheap little chinese made one that works fine.

One the flux is applied, you then apply soldering flux. prips is not
a highly active flux, and won’t work especially well for soldering,
though if your joints are clean and tight, the solder clean, and your
technique good, it can work. Usually, though, one applies additional
soldering flux JUST TO THE JOINTS. soldering fluxes don’t protect from
fire scale as well, if at all, since they tend to burn out too
quickly. The white paste fluxes especially tend to do this. When I
do this, I usually apply the prips flux to the seperate pieces being
assembled, let them cool again, then gently set up the soldering
operation after they’re cooled. I use a liquid soldering flux
(batterns), and the liquid dissolves enough of the prips crust at the
joints to let the pieces contact enough other properly.

After soldering, the prips comes off in either hot water or faster,
in pickle. the metal may have a slightly dusty whiter appearance, but
when you go to polish, you won’t find that subsurface fire scale that
can be such a bane to polish off.

Made By Hand

Leesburg, Florida

   I seem to have lost the recipe I downloaded here for prips flux,
and can't find it in the archives. Could someone please post it

About a liter of water, boiling.

120 grams Boric acid

80 grams borax ( I use the grocery store, laundry aisle, stuff.
Borateem is virtually pure borax with a bit of some blue dye/bleach or
something, which doesn’t seem to hurt the flux at all. 80 grams sodium
phosphate This can by monosodium phosphate, disodium phosphate, or
trisodium phosphate. All work. The first two are usually chemical
supply house items. The third is TSP, often found in paint/hardware
stores as a cleaning agent. Be sure it’s really TSP, rather than one
of the very common phosphate free substitutes, which won’t work

dissolve the three chemicals in the boiling water and allow to cool.
Sometimes needs a little addtional water to fully dissolve or keep it
all in solution once cooled. You can use more water or less chemical
too. I’ve seen this same weights of chemicals used with a gallon of
water too, in schools using big spray bottles to apply the stuff to
holloware, where overspray wastes a good deal. More dilute also
doesn’t so quickly clog the spray bottles. But you then need to apply
a lot more to get the desired result. In any case, the important
thing about the quantities is the 3:2:2 ratio of the weights. The
actual amount you use, or concentration of the chemicals, is up to

If any of you want a copy of the article I wrote a few years ago here
on orchid (and elswhere on the net) regarding the use of Prips flux,
feel free to email me for it. Should be in the archives though. check
not only “prips”, but the misspelling “pripps”. I’d mispelled the
name in that article, a mistake that seems somehow to be propogating
over the web now and then… (oops. Apologies to Jack Prip)

Peter Rowe


I have been using Prips Flux which I buy from a company called the
Casker Company out of Cincinnati. It is made by the Griffith
Company. Casker does not actually have it shown in their catalog
but they were able to get it for me. If interested their number is
1-800487-5848. I also remember some time back ordering it directly
from the Griffith company out of NJ (I think??), but it cost about
the same. I would assume since it is called Prips flux with a "TM"
notated after the word Prips that it is the same formula you guys
are talking about. It is expensive to ship because of the weight
but I am happy with it’s performance.




There are a number of commercial products that can be purchase that
will stop oxidation. StopOx is one that comes to mind and I know
there are others.

But, why purchase Prip’s flux and these other things when you can
make it in just a few minutes and for small amount of change.

You can buy 85 gm bottles of boric acid at the pharmacy or
supermarket for less than $2.00, a 1 lb (454 gms) box of tri-sodium
phosphate (TSP) at any paint or hardware store about $2.00 and a big
box of Boroteem borax powder at the supermarket for a couple of

Go to the Orchid archives and you will find the formula how to mix
these items ingredients with warm water. Make a quart (it uses 80
gms of the boric acid but you will have enough of the other items to
make several quarts later) and it should last you quite a long time.

Cheers from Don at The Charles Belle Studio in SOFL where simple
elegance IS fine jewelry! @coralnut1


I want to make a batch of Prips Flux. I bought a box of TSP at
the hardware store. When I brought it home I noticed that it
included Sodium Carbonate in addition to TSP. Can I use this
mixture to make the flux or do I have to find pure TSP? Help
would be appreciated. I want to sweat solder silver to copper
and want the strongest possible flux to counter act copper’s
tendency to oxidize rapidly. Thanks for the help. Sarah


Pripps and TSP? For a traditional Pripp’s type flux one would mix
denatured alcohol in a glass or ceramic vessel and borax until a
saturated solution is achieved, and its a done deal - no TSPl!.I .

Sodium carbonate is an oxidizer usually used in gold refining flux
recipes (in addition to borax in most recipes) although I use sal
ammoniac for my refining flux.

4S labs has been making Cupronil for many years- its a time tested
consistent flux redily available from any vendor- its a borax based
flux that works brilliantly for all soldering operations and any
metals you wish to join-particularly mixed metals (due to the
oxidiser in it.) Barring making your own Pripp’s mixture I highly
recommend Cupronil as it always gives you consistent results without
any guessing what went wrong after -the-fact. Making your own flux
solutions is cheap, quick and mostly effective ;but results may vary
batch to batch (especially if you use impure ingredients like the
borax intended for laundry -it will work but isn’t crystalline borax
without fillers that yields variable results)


no TSP

I suppose you could call that a Pripp’s type flux, and it probably
works well, but re-read Peter Rowe’s article:

Al Balmer


Despite what RER says Prips is water based not alcohol based. The
"TSP" you bought probably does not even have TSP in it. Most of what
I have seen in the stores over the past few years may say TSP on the
box in big letters but when you read the ingredients it is actually
other chemicals. TSP has been phased out of all consumer products in
most states due to its role in promoting massive algae growth when it
gets in waste water and eventually ends up in rivers and streams. The
sodium carbonate in yours is another good cleaning product that is
not such a good fertilizer but will not do what you want for a
soldering flux. You can buy tri-sodium phosphate(TSP) or di-sodium
phosphate from chemical supply houses either one will work. Or you
can buy pre prepared versions of Prips flux. Cupronil, Rio’ Stop-Ox
II or Griffith’s Prips Flux are available from your favorite jewelry
supply house. They are all essentially the same stuff with a little
dye added to them. Much easier than making your own.

James Binnion

You can buy tri-sodium phosphate(TSP) or di-sodium phosphate from
chemical supply houses 

Real TSP is still available at retail stores, at least in NYS.
Actually, Amazon sells it anywhere as far as I know. But you are
correct that care is needed to get the real stuff, not a substitute.

Al Balmer