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Borax for flux? What is really the best?


I have been hearing from a few people that they use straight borax
for flux. I ran out of my flux mid project and decided to give it a
try and it worked pretty good. I have used several different fluxes
before, from handy flux, superior flux, dandix, firescoff, but I
really don’t have enough experience or side by side comparison
experience to say that I really loved one over the other. In reality
the borax seemed just as good. I have used Dandix the most and it
seems to be a standard amongst people I have talked to. I just
wanted to see if anyone has really compared options. I guess I am
cheap and wondering why not to use borax if it is cheap and

I would love to hear what people have to say.

Blaine Pengelly


I guess I am cheap and wondering why not to use borax if it is cheap
and plentiful?

I use boric acid that I buy cheaply from the pharmacy of my grocery
store in the band aid section and methyl alcohol that I order from
Indian Jewelers. Works just as well as any flux I’ve ever bought.
Admittedly, I have some Firescoff that I have yet to open and try but
I hear that is good as well. Most of the flux you buy is just boric
acid and alcohol, I believe. The Handy flux that I have gets dry and
I have to thin it down with alcohol anyway, so what’s the difference?


There is a difference between borax and boric acid- it is in the
chemical reaction produced when heating boric acid and the extra O2
given off that is too lengthy to go into here but is noticeable in
the results in flow of flux and oxide build up (or lack of it)
particularly if using sterling or other copper containing alloys
like low karat golds, etc.

Borax is superior to boric acid, though in refining your scrap
(mixing at least 50% 24 kt casting grain with scrap gold and
whichever metals you require to make x alloy or in raising /lowering
karats in golds) adding boric acid to the metals in the glazed (
with borax!) crucible yields a tougher cleaner ingot that will roll
out better and resist tearing, splitting, etc. An improvement on
that is to combine powdered charcoal, sal ammoniac and boric acid
(5:2:3) and use a large pinch (though relative not more than 1/4 tsp
in any case) to your reclaimed metals…but back to Borax It is
historically the most consistent and reliable and reaadily available
flux. Improved on only in a product like Cupronil that provides
anti-firescale properties as well as (and is equally consistent as)
traditiional borax surpassing alcohol and borax dips, and far
superior - in my opinion to new “ceramic” containing anti-firescale
flux products. Pure borax in cone form is best, though 20 mule team
borax, as for laundry will work too. If you prefer a paste flux you
can mix the borax (powdered with a number of waer soluable vehicles
to make a product with the consistency of, say handy-flux ( for
reference only not as an endorsement of the stuff). or dandix paste.
Borax and water help indicate the flow temperature is about to be
reached as it clarifies on the heated metals. ou can also build up
layers of borax by warming the metals and applying,cooling then
repeating (that is why Cupronil is ideal- its even spray - on
application of borax,etc. easily achieves layers with warming in
repetition and solder flows fast and without time to allow oxides to
build up on a work-piece). finally placing your paillion or moving a
ball of solder, sweating it or any method preferable to get the work
joined. Bottom line, borax is cheap, consistent superior to boric
acid and works on all metals that are non-ferrous. I have compared
ad nauseum fluxes, read threads on Orchid and other forums about
borax vs. x and barring Cupronil (borax based), plain old borax has
more uses aroind the studio than any other chemical except pickle.



Hi Blaine,

I am a trade trained English goldsmith, six years apprenticeship
started in 1961 followed by a lifetime at the bench which now totals
48 years. I have never used any other flux than a simple Borax. I use
a Borax cone in a standard round ceramic borax dish, the borax is
mixed with water in the dish. I use a few sizes of old water colour
paint brushes to apply the flux to the articles. This fluxing method
has served me well for 48 years so I see no need for changing, the
term “if it aint broke why fix it” comes to mind. Borax flux works
well on most standard metals when using standard solders.

Take a look at my gallery on orchid

everything shown on my gallery was soldered using Borax as a flux. I
use a dilute solution of sulphuric acid and water as a pickle,
something else I have used for the whole of my career. I am sure
there will be many who use different fluxes and chemicals, but us old
timers find change hard. If anyone is interested in seeing more of my
work, a book "The Work of a Master Goldsmith;a Unique Collection"
will be published at the end of May this year. I have ordered my
copies from Amazon UK, as they are offering the book at good discount
and at a price cheaper than the one my publisher is quoting me, the

I wish peace, good health and full order books to all.
James Miller FIPG


Borax is a basic ingredient of most of those fluxes. It works fine as
a flux but it has a high melting point (1365 F) so the metal has lots
of time to oxidize while you heat it hot enough to melt the borax.
This is not a problem on 18k or higher yellow golds as they doesn’t
oxidize much but on other metals you probably will find that there is
a lot of oxide that forms while getting hot enough for the flux to
melt, this depletes the flux and reduces the protection time that the
flux provides. Most paste fluxes for silver and copper are composed
of boric acid, borates (borax), fluorides, fluoborates and wetting
agents. Borax alone or with boric acid tends to be quite viscous so
it doesn’t flow well in tight joints and crevices and it also is hard
for the molten solder to push it out of the way. The fluorine
compounds are added to paste flux to reduce the melting temperature,
increase fluidity and increase the ability of the fluxes to dissolve
oxides. Commercial paste fluxes are going to give you better
performance in most cases than plain borax.

James Binnion
James Binnion Metal Arts

I just wanted to see if anyone has really compared options. I
guess I amcheap and wondering why not to use borax if it is cheap
and plentiful? 

I wrote an article for our local guild on this subject-- here it is:

Gem of an Idea: Fluxes
By Noel Yovovich

We all use fluxes. And we all have at least occasional difficulty
with soldering, and sometimes we have trouble with firescale.
Myself, I keep about half-a-dozen different fluxes on my bench, and
if things are not going well, I’ll try a different one, or use more
than one. My thought process is something like "The soldering
goddess doesn’t like this one today, maybe she’ll be happier with
another one."A while ago, after reading glowing testimonials, I sent
for a free sample of Firescoff, a “revolutionary” new type of flux,
or so they say. The sample was so tiny that I couldn’t finish a
piece of jewelry with it, but it was intriguing because when I
washed the piece after soldering, it was still bright and shiny.
That got my attention!

So when I decided that I would do some actual testing of fluxes,
both for this column and for my own benefit, I ordered a bottle of
Firescoff. It is quite expensive, compared to other fluxes-- $25 for
a 4.25oz bottle. And because you spray it, a lot of that is going to
be wasted. But if it truly lived up to its hype, well, maybe it
would be worth it. My standard flux for several years was borax and
alcohol. I like alcohol flux because the alcohol evaporates or burns
off quickly, so there’s no boiling and bouncing that moves the
solder snippets out of position as so often happens with paste
fluxes. A few months ago, I came across Magic Flame flux, which
comes in a jar as a thick paste and can be mixed with either water
or alcohol.

I now keep a jar of this, with alcohol, as my usual flux, but
recently I have been more and more enamored of the fluxes that are
sprayed on hot metal. If the spray is really very fine, you can get
a very even coating with no gaps by spraying while heating, bringing
the temperature back up between sprays so that the flux dries on
contact. An even coating should mean no firescale, right? There are
many more flux es than I tested, so your favorite may not have been
included. I was reluctant to commit more silver than I already used,
since all of it will just goin the “refine” bucket.

So I apologize that these tests were not more comprehensive, but I
hope they are of some use.I tested:c Magic Flame ™, made of boric
acid, borax, and sodium fluoborate, $12 for 8oz at Rio Firescoff
™, which the company’s web site says “combines a scale preventer,
a high performance non-fluorinated flux [and] a revolutionary heat
activated ceramic spray coating”, $25 for a 4.25oz bottle from
Nventac Cupronil {tm), containing borax, boric acid and disodium
phosphate, $13 for 16oz from Rioand, to round things out,

Handy Flux ™, “contains fluorides, potassium and hydroxide”,
$10.75 for a pound.The first test I tried consisted of soldering a
piece of square wire to a strip of 20g silver that I divided into 4
sections. I applied flux to each section by the preferred method,
covering the other sections when I sprayed. I used hard solder in
all tests, and used a Meco Midget propane/oxygen torch. I was so
surprised by the results that I repeated the same test. The results
were the same. Just to be sure, I did one more, in which I cut four
separate squares of 24g sterling, 3/4" x 1".

My thinking was that this gauge sheet would require less heat and
would be a slightly less demanding test, even with hard solder. I
applied one flux to each, then flooded the backs of four
machine-made bezel cups with hard solder, placed a bezel cup on
each, and heated around the edges of each sheet until the solder
flowed. After pickling for an extended time, I lightly sanded all
the pieces and examined them. The results matched the other two
tests.The worst-performing flux was Handy Flux, which showed
firescale over about a third to half of the surface. Cupronil and
Firescoff did about equally, with firescale on about a quarter of the
surface area. With Magic Flame, there was no firescale at all.

After talking to some other metalsmiths about these results, I did
just the bezel cup test on two more fluxes: purchased Prips (boric
acid, borax and trisodium phosphate, $5.88 for 8oz at Contenti), and
Rio Grande’s My-T-Flux (boric acid and ammonium chloride; $8.50 for
16oz.) The My-T-Flux did pretty well, with firescale on about 10% of
the surface; Prips did badly, with maybe 80%.The proponents of each
of these products have said that with their preferred flux, they get
no firescale, so it seems likely that personal soldering style makes
a difference in the results. If that is true, then my tests may not
apply to you. This kind of test is very easy to try with whatever
flux(es) you have on hand.

Even if you have just one, you can try what I did and look at the
results. Firescale is most visible on a sanded (rather than
polished) surface, especially if it is held vertically, perpendicular
to a piece of white paper. Also, this is a pretty harsh
test"personally, I do not typically do this kind of task with hard
solder. I use hard for soldering bezel seams and not too much else.
So bear that in mind when evaluating these results. If you do any
tests, please let me know how they come out! My conclusions after
this experiment:

The spray bottle used for sprayed fluxes makes a big difference.
Firescoff’s bottle sprays so fine that the spray dries instantly
without getting thick. Cupronil’s sprayer tends to wet the surface
because the droplets are large, and wetting causes beading up and
pulling away from areas.

The flux that is best for hard solder may not be best for other

Personal style may be a factor in what flux will be the best choice,
so buy a few fluxes and try them. Consider doing a test like mine,
rather than rely on “anecdotal” evidence by just working with the
different fluxes.

Consider switching to Argentium{tm) sterling so the whole question
of firescale becomes irrelevant. Why don’t I? I own pounds of
sterling stock of all sizes and shapes, plus I’m reluctant to learn
new habits, I guess. By the way, I have not put Firescoff to the
test in terms of not needing to be pickled. The claim is that you
can just soak pieces in hot water, and eliminate the use of pickle
solution altogether. This could be very useful in some situations,
especially if heated parts don’t need re-polishing when soldered
with Firescoff. But this test was all about firescale. I will say
that it seemed as though the solder flowed better with Firescoff,
but that is not a scientific result. “Your mileage may vary!”

I guess I am cheap and wondering why not to use borax if it is
cheap and plentiful? 

You ARE using borax, Blaine. All of those things you mention are more
or less borax - it’s just a delivery system and convenience. Some
have fluorides (the word “flux” comes from “fluoride” in a roundabout
way, ya know… “to flow”) I’ve used Battern’s or some brand
forever because it works for me but largely because it’s clean.
There’s nothing worse than having borax snowflakes permeating the
air…Plain old borax is low-tech, but in almost all cases it
WILL do the job. It’s just those snowflakes


James, your work is exquisite! For us Americans, what is Borax cone
and ceramic Borax dish? Could I just use a simple ceramic glazed

Again, your work is absolutely gorgeous!



Thanks Noel for your time and sharing your flux info. I have been
experimenting with flux forever and thought I was retarded. I have
found the same results as you have. I did try Firescoff with your
same results. I find Firescoff is great for a repair when you do not
want to pickle the entire piece and repolish - like a simple jumpring
repair on the middle section of a bracelet. Other than that use I
cannot justify it’s expensive price tag. I do like the spray bottle
and the fine mist. Anyway thanks again for your info. Like you said
everyone’s torch technique/skill is really a factor too. The amount
of heat occurring with the amount of time.

I will keep trying to satisfy the Soldering Goddess. :slight_smile: Joy


if you use a cone and dish, you don’t get snowflakes. I think
perhaps it’s a regional thing, too - I’m in the UK and learned how to
solder using a borax cone for flux. works absolutely fine for me.




James, your work is exquisite! For us Americans, what is Borax
cone and ceramic Borax dish? Could I just use a simple ceramic
glazed dish? 

Thank you for your comments on my work. Over here in the UK most of
our jewellery tool suppliers sell Borax cones and dishes. The Borax
dish is an unglazed dish that has a slight abrasive action, the
method of producing the flux is to have a small amount of water in
the dish and when the borax cone is rubbed in a circular motion
within the dish, the slightly abrasive action of tye dish creates a
milky liquid that is the flux, this dries up gradually and forms a
coating within the dish so te next time you need flux, less rubbing
of the borax cone is required. To clean out the borax dish I just
pour hot water into it and the borax coating dissolves and leaves
you a clean dish. My latest borax dish has lasted me for 25 years now
and is a good as new and it only replaced the previous one when I
dropped it on a concrete floor and it shattered, the original dish
had been used by me for twenty years so in 45 years I have only used
two dishes. A borax cone will last me at least a year. If you take a
look at this page from a website you will see a Borax cone and a
Borax dish. I just googled the words Borax cone and dish and this
company was top of the page, this page shows the items,

I would be very surprised if these products are not available in the

James Miller FIPG

if you use a cone and dish, you don't get snowflakes. I think
perhaps it's a regional thing, too - I'm in the UK and learned how
to solder using a borax cone for flux. works absolutely fine for

It also has a lot to do, from what I understand, with the way the
borax cone is prepared versus “laundry aisle” borax. The cones are
made from anhydrous borax. That’s borax that has been preheated
enough to drive off the water of crystalization. The result is borax
that doesn’t bubble up uncontrollably as you heat it, even if you’ve
prepared it by grinding the cone into water to make a paste. That
water isn’t chemically bound to the borax. At least, that’s how it
was explained to me, last time I asked about that…



When I asked my local supplier (who had the cone, but not the dish),
they told me to get a chinese ink dish, which seems to do the job
nicely. (And looks very spiffy too)



Does anyone know if the Borax Cone is available in the US?



Wet sanding paper of a fine grid will do the same job for you and
lasts forever. KISS, keep it simple…

I’m using it for years now without any complains.

Have fun

Does anyone know if the Borax Cone is available in the US? 

The only place I found in the US is:

Item 54.252-1 borax 4 oz cone @ $7.45 each

They don’t show the little plate or dish but that is no big deal.

They are a very good supplier with good prices.



contenti does one:

and friends in the states have said that they are available at
Metalliferous as well.


I am so surprised that nobody has mentioned Boraxin. It is a miracle
to work with! It is not sold in the US, so one must order it from
Fischer in Germany (for the best price) but it is the very best flux
I have EVER used. You can dilute it up to a 50:50 solution and then
it will work even a bit better since it takes some of the inherent
stickiness out. I use pure water, never tap, in anything I dilute,
even to make my pickle.

I like Boraxin so much, I will throw away the Handiflux I have and
not even give it to someone who would just be frustrated. Why foist
something like that on a beginner? If you order anything online from
Fischer, choose the least expensive shipping and you’ll have it in 10

  • 14 days. I am in Tampa and my order arrived 9 days from the day I
    ordered it. Lovely people to work with!


I am so surprised that nobody has mentioned Boraxin. It is a
miracle to work with! It is not sold in the US, so one must order
it from Fischer in Germany (for the best price) but it is the very
best flux I have EVER used. 

I found Fischer’s URL after a few minutes’ searching:


Hi Nel,

Do you use Boraxin strictly as a flux, or will it work as a firecoat
as well? I currently just use borax and alcohol for that purpose.

Jessee Smith
Cincinnati, OH