Struggling with pripps flux

Jewelry Discussion
1

Can any of the Pripps gurus tell me where I’m going wrong? I made
some Pripps flux according to all the recipes and am frankly
struggling to have any success with it. My first problem is knowing
at what stage to spray on the flux. How long do you heat the piece
before spraying it on? Sometimes it works ok, but sometimes it just
goes on wet and it’s difficult to get coverage so you still end up
with the leopard spots and possible firestain. My second problem is
that when I use Pripps, I can’t get anything to solder. The solder
just won’t flow when the work is coated with Pripps. The third
problem is that I’m having to heat everything even hotter than usual
in an attempt to get the solder to flow. I had everything at red heat
for over ten minutes but nothing would melt. The snippets of solder
wouldn’t even melt enough to ball up! I repeatedly stopped, pickled,
rinsed, re-fluxed and tried again - all to no avail. Yes, it’s great
in that you get no firestain, but if you can’t even solder one piece
of metal to another, there’s not much point in it - heating up metal
for no purpose whatsoever. I must be doing something wrong.

So I’m back to using boric acid in alcohol and filing away
firestain. Any advice will be very much appreciated, thanks.

Helen Hill
UK

2

Helen,…It does take awhile to get use to using Pripps flux but
once you get the hang of it, its pretty easy.

My first problem is knowing at what stage to spray on the flux.

The first thing you need to do is lightly sand all pieces being
soldered to remove any oils that might have been used during the
manufacturing process. This is especially crucial when using new
plate or wire. Then dip the pieces being soldered into denatured
alcohol. That cleans off any finger oils that might have accummulated
by handling.

How long do you heat the piece before spraying it on?

After dipping it (or painting on the alcohol if its a large piece
that won’t fit into the alcohol pot) warm it with your torch. The
alcohol will flame off and warm the piece suffieiently.

(S)ometimes it just it goes on wet and it’s difficult to get
coverage so you still end up with the leopard spots and possible
firestain.

After spraying or dipping it, immediately heat it with your torch.
The Pripps will turn white. Stop as soon as it turns white all over.
If there are spots where it did not take, spray (or brush) more
on…let it set for a few seconds (don’t breath the resultant vapors,
they are not good for you) and heat it again. By the second or third
time, the entire piece should be white. Do not over heat it. If it
begins to turn golden or yellow, you have over heated it. No big
problem but, the next time use less heat.

My second problem is that when I use Pripps, I can’t get anything to
solder.

Pripps flux is a protective flux…not a cleaning/wetting flux.
After you apply the Pripps, you can do your set up (you can handle
the pieces - no problem) and then must use a cleaning/wetting flux
such as Batterns, or one of the other liquid fluxes - BUT ONLY ON THE
JOIN. This should solve your problem with solder that won’t flow.

The third problem is that I’m having to heat everything even hotter
than usual in an attempt to get the solder to flow.

Not sure why this is happening. It could be contamination but I
doubt the Pripps has anything to do with it unless the borac acid in
the mix is interferring. Using the second flux should resolve that
problem.

Let me know if this solves your problem. We use both Pripps
(protective) and Batterns (cleaning/wetting) fluxes at the school all
the time and have no problem with solder flow if…everything is
clean, the torch has the right tip, etc, etc.

Cheers, Don

3

Clean,

Clean, Clean, and I mean CLEAN, Keep your hands clean, keep solder
clean, if any thing, any thing is oxidized, clean it, do you get the
point??? I have Phipps and a row of fluxes for the people to use
when they come over to do things and they watch me work and ask "
why don’t you use flux/ I say - - Did you see that flow and run by
pushing the solder with the flame? They look at me like at a distant
far away place and then say " how did you do that, I say, stick
around for a decade or two and I’m sure you will eventually get-it. I
put a $60,000.00 22Kt, only pure gold and pure silver, Patient and
Chalice together using only precious metals, (no alloys, hand made
solders), and pure silver, ruthenium, platinum, iridium, 6.5 Lbs.
and 2 years. You can to, just keep everything clean-clean.

Stephen Wyrick, CMBJ
Gemmologist

4

Hi Helen,

You have to heat the metal hot enough to evaporate the water
carrier. That takes a little practice. If the Pripps goes on wet and
puddles the metal is not hot enough. When the metal is hot enough
Pripps will immediately form a white crusty coat as you spray it on.

A fine mist sprayer will help.

I do not believe Pripps is a good flux for soldering. I suggest you
us a very small dab of paste flux where ever you want solder to
flow. Be careful as paste flux will flow and wash away the protective
coating and you will get a ring of fire coat around the joint.

You should not have to heat the project any hotter than you have
been if you have paste flux at the solder joint.

Those of you who know me may ask why as a manufacture of Cupronil I
tell how to use a competitor anti fire scale flux. I hate fire scale
so much I would encourage all to use any of the anti fire scale
fluxes to eliminate fire scale. There is absolute no reason to suffer
the problems fire scale causes.

If I can be of any additional help contact me.

Down with fire scale. May it pass into oblivion…

Lee Epperson

5

hi helen,

I’m certainly no expert solderer, but I do use pripps and maybe some
of my trials will help you!

I’m not familiar with “mixing up a recipe” of pripps, as the solution
I use is ready to go right from the bottle. what I learned from a
wonderful jeweler (pauline warg, just to drop the name), is that in
order for the pripps to adhere “correctly” you need to gently heat
your piece first. if it’s not heated enough it will puddle, and if
it’s heated too much, the brush will stick to the piece. it’s
actually not very difficult finding the correct middle ground. (oh,
and don’t drown it) another piece of wisdom that has helped me time
and again, especially with my bigger pieces, is to use a tripod with
a screen and begin by heating the piece from underneath.

and the last thing that has worked for me is, even though it may seem
incongruous to the size of what I’m working on, I’ve found using a
larger torch tip can really make a difference in getting the whole
piece hot enough quickly. oh, actually one more thing: since I’m
just fabricating an original that I then get cast, sometimes if I’m
having trouble with say, my hard solder, I’ll get it all cleaned off,
and then try the medium. I’d be curious if any of these things help!

good luck–
Davida Newman
www.daletdesigns.com

6

Helen,

Strange problem about your solder not flowing. I use pripps for
firescale and as my main soldering flux, almost always just hard
solder. One thought is that maybe you got ‘fake’ TSP. The real stuff
is getting harder to find and the fine print ingredients on the fake
stuff smaller and smaller.

I heat the piece a little above the boiling point of water and dab
the flux on with a brush. Torch in one hand and brush in the other,
re-heat if the flux goes on wet. Continue until everything is white.
Solder as normal.

Jeff
Demand Designs
Analog/Digital Modelling & Goldsmithing
http://www.gmavt.net/~jdemand

7

Dear Don, Stephen, Lee, Davida and Jeff,

Thanks for all the tips re using Pripps. I’ll give it all a try and
see how I get on.

One thought occurred to me. Because I had read that Pripps is not a
good soldering flux, I had been dipping each piece in boric acid in
alcohol and flaming off the alcohol and then spraying on the Pripps.
I wondered whether perhaps I’m interfering with the correct ratio of
ingredients by introducing more boric acid and maybe that was my
problem. So I did some pieces yesterday without dipping them first.
To my surprise, they soldered. But, the solder joints were lumpy,
copper-coloured joints which I didn’t like so maybe I do need a
suitable soldering flux just at the joints as you’ve pointed out.

As far as clean, clean, clean is concerned, I haven’t had a problem
getting solder to flow for a long time (since starting to solder
last year), as I do keep everything clean.

Many thanks,
Helen
UK

8

Hi Jeff,

I use pripps for firescale and as my main soldering flux, almost
always just hard solder.

So you can use it as a soldering flux? Others are saying it’s not a
soldering flux, just a protective flux. I use hard solder pretty
exclusively too.

One thought is that maybe you got 'fake' TSP. The real stuff is
getting harder to find and the fine print ingredients on the fake
stuff smaller and smaller.

No, I bought lab grade TSP from a chemical supply company so that’s
not a problem.

I’m spraying the Pripps on after heating the piece, but I’m
wondering if my spray bottle has too coarse a spray as it drowns the
piece in one go and I have to boil off the water. Then if there are
any gaps when it dries, I spray again and it puddles again! It’s a
bit of a nightmare really.

I’ll try the various suggestions and see how I get on. Thanks for
the advice.

Helen
UK

9 
So you can use it as a soldering flux? Others are saying it's not
a soldering flux, just a protective flux. I use hard solder pretty
exclusively too.

Yes, for silver with or without the fire scale coating, gold with
the flamed boracic coat first (boracic not boric… different active
temperature ranges !!! ) Even brass and copper if I am quick enough
to avoid burn off. I do tend to solder very hot and fast with an oxy
torch (acetylene or propane). Closer to a gold style than a gentle
over all heating traditional silver technique. But even an
acetylene/air torch and a more proper silver technique doesn’t cause
problems. Maybe I’m just not very fond of following the “Rules” If
you know and understand the rules it is easier to ignore some of
them, just not the ones which will kill ya :slight_smile:

Nasty white (and black) fluoride paste for big and slow copper
alloys and steels. Somewhere in the back of the cabinet are bottles
of blue and green flux which I have used in the past but I find no
need to have too many bottles of flux on my bench.

When spraying or brushing on a pripps fire coat layer the piece has
to be hot enough that there is never any liquid on the surface. If
you miss a spot re-heat and spray again

Demand Designs
Analog/Digital Modelling & Goldsmithing
http://www.gmavt.net/~jdemand

10 
Yes, for silver with or without the fire scale coating, gold with
the flamed boracic coat first (boracic not boric... different
active temperature ranges !!! )

Thanks Jeff, some great advice. I’ll have to look out for the
boracic acid for when I want to solder gold.

Helen
UK

11

They are the same thing, boracic is a different name for boric acid.
Boric acid, also called boracic acid or orthoboric acid or Acidum
Boricum are all H3BO3

James Binnion
James Binnion Metal Arts

12

Jeff, in your post on this, you said:

coating, gold with the flamed boracic coat first (boracic not
boric... different active temperature ranges !!!

As far as I can tell boracic acid IS boric acid, see the Wikipedia
article on boracic or on boric acid. I think you are confusing boric
acid and borax, both used as fluxes and fire coats and having
different active temperatures.

Marlin

13

OK, I made a mistake on the boric and boracic acid. Sorry to have
sent Helen off searching for something she already has. Marlin is
correct, I was thinking about borax and boric acid.

Jeff
Demand Designs
Analog/Digital Modelling & Goldsmithing
http://www.gmavt.net/~jdemand

14 
OK, I made a mistake on the boric and boracic acid. Sorry to have
sent Helen off searching for something she already has. Marlin is
correct, I was thinking about borax and boric acid.

No worries Jeff. I already use boric acid in alcohol for sterling so
I’m glad to know it’s okay for gold too. I’d not got round to
looking up boracic acid but would quickly have found out that they
are one and the same thing, but thanks to Marlin for clarifying
things.

Helen
UK