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Prips flux not dissolving


#1

Hello all,

I need more help with the making of prips flux. The chemistry
teacher at school made me a batch from the following formula which I
found in the archives: 120 grams boric acid 80 grams borax, 80
grams sodium phosphate plus about a quart of boiling water.

According to him the sodium phosphate is not a chemical easily
dissolved. It certainly did not stay dissolved when it cooled down
for me.

What is going wrong. Please tell me what and how to mix this as he
is leaving on vacation in one and a half weeks and I want to try
using it this summer.

Thanks a lot in advance and keep on being happy out there around the
world fellow jewelers.

Sharron in sunny and today, not rainy, Saigon.


#2

Hi Sharon, as fate would have it, I just had to make up a huge new
batch myself last week. I think you used the wrong proportion of
water–should be 2 QUARTS, not 1…naturally you have loads of
precipitate that can’t fully dissolve.

I make it simple–a big plastic bucket, add the ingredients and use
very hot tapwater–keep stirring like a witch’s brew and then I funnel
into small plastic bottles. Probably enough for the year. Tip–try a
good plastic spray bottle from a hobby shop for easy application
(clogging is rare with me). Regards, Marty R.


#3

Sharron, the ingredients for PRIPS FLUX are Borax, Tri-Sodium
Phosphate and Boric Acid. I think there may be a significant
differance between Sodium Phosphate and Tri-sodium Phosphate. I am not
a chemist but this may be why you’re having trouble. Tri-Sodium
Phosphate or TSP is a commonly available cleaning agent available in
most hardware stores.


#4

Hi Sharon;
Just another idea for you. I use a stainless steel pot to
mix up my Prips flux ingredients in. I then put it on a one burner
electric hot plate and heat it rather than try and use hot tap water.
I do not let it boil or even get to the small bubble stage but to the
point I can see steam coming off of it. I use a wooden spoon to stir
the ingredients,and within minutes the solution is as clear as tap
water,completely dissolved. I then just set it aside to cool before
putting it in acid proof plastic bottles. Hope this
helps,regards, John Barton, Images By JJ


#5
I then just set it aside to cool before putting it in acid proof
plastic bottles. 

Any bottle will work. I can’t think of a container you could use
that would be attacked by the chemicals in prips flux. Boric acid may
be chemically an acid, but it is a very weak one, safe to use around
human bodies and metal containers alike. A solution of it does not
attack metals at all. When molten, it dissolves oxides of metals.
But pretty much any container you’re likely to have around is safe for
prips. About the only container problems you’ll see is that prips
flux, if allowed to sit in a spray bottle, will dry out, leaving a
crust of dried flux. Not very surprising. Neither is the fact that
this crust can clog a sprayer…

Peter Rowe


#6
   Sharron, the ingredients for PRIPS FLUX are Borax, Tri-Sodium
Phosphate and Boric Acid. I think there may be a significant
differance between Sodium Phosphate and Tri-sodium Phosphate. I am
not a chemist but this may be why you're having trouble. Tri-Sodium
Phosphate or TSP is a commonly available cleaning agent available
in most hardware stores.  

There is no practical difference in prips flux made with monosodium
phosphate, disodium phosphate, or trisodium phosphate. All work
essentially the same. The sodium content is unimportant, it’s the
phosphate you need, but the formula is not critical enough for the
precise source of it to matter, despite the fact that there will be
more phosphate content if mono or di sodium sources are used. And TSP
is so much cheaper than the others, which usually must come from
chemical supply houses as reagent grade chemicals rather than
hardware store cleaner.

The recipe I’ve always used is ONE quart of ordinary tap water, 80
grams each of borax and TSP, and 120 grams of Boric acid. It’s the
2:2:3 ratio of the chemicals that matters, not the quantity of water.
In one quart of water, boiling, the above chemicals will not quite
dissolve completely, so you then add sufficient additional water to
finish dissolving them. The idea is to make up the most saturated
solution you can, so you don’t have to spray so much to get sufficient
coverage. But there’s nothing wrong, really, with making it up much
more dilute, if you wish. I got that original formula listed above
as an undergraduate, and it fits the way I work, with a mouth atomizer
for applying the flux. But when I was in grad school, different
program, they tended to use trigger spray bottles with the
undergraduate classes, which are a lot less precise in aim, clog more
easily, and go through flux a lot faster than a mouth atomizer. So
they’d mix up those chemicals into a GALLON of water. You needed a
bit more spraying, but the kids didn’t seem to have trouble with it.

The stuff doesn’t dissolve easily in cold water. Needs to be
boiling. And as noted, the quart of water isn’t actually quite enough
to keep it in solution once it’s cooled again. You need just a bit
more.

This isn’t critical or precise chemistry, folks. Like I said, just
the 2:2:3 ratio of the chemicals is important. Other than that, do
whatever you like and it will still work fine.

If anyone needs more help with prips, please email me. It’s pretty
easy to use, and works so well it’s a shame if anyone avoids it’s use
because they haven’t figured out how to use it.

Peter Rowe


#7

Peter Is Prips Flux the same as a commercial product Rio Grande sells
called “Cupronil”? It is a blue liquid flux.

Thanks
Marianne Holden, Toronto


#8

I have been watching this thread for some time and have been unable
to find TSP in central Florida could someone help? Would like to try
Prips since we do quite a bit of silver work. Thanks in advance.

BillyBob
Made By Hand


#9

Go to your nearest hardware or paint stote (Home Depot). You can get
a 2 or 3 lb box (a life time supply) for a few dollars. House
painters use it as a prep on walls before painting.

Cheers
Virginia Lyons


#10

BillyBob, I’m surprised you can’t find TSP. Just about any paint
store carries it these days. Or try a SEARS paint dept or better
still if there is a Home Depot or a Lowes around, they certainly will
carry it. Good Luck and Cheers from Don at The Charles Belle Studio
where simple elegance IS fine jewelry!


#11
   Peter Is Prips Flux the same as a commercial product Rio Grande
sells called "Cupronil"?  It is a blue liquid flux.  

In a word, no. Prips is one you make yourself, and it’s colorless
when mixed up. I’m not sure what’s in cupronil. Might be fairly
similar, but at the very least, prips isn’t blue. And prips is a lot
cheaper, since you can make it yourself by the gallon if need be.
Cupronil, from what I read, is designed more for use on copper, so
that oxides either don’t form or more likely, flake cleanly off of
copper after firing. That wouldn’t need, among other things, quite
the same formula as prips.

Peter