To Borax cone or Not Borax cone

To Borax cone or Not Borax cone that is the Question

Hi Guys,

I’m interested in people’s thoughts about borax.

In particular there are borax cones that you have to grind up and
then there’s powdered borax.

Why do people use the cone over the powdered borax, it’s just
something I’ve been curious about.

Regards Charles A.

HI Charles,

I learned with a borax slate when I was in college, but I don’t use
it now. (Still have it, mind you) Modern fluxes work better.

It’s a good, convienent way to do a very basic flux (borax + spit)
but if you don’t already have one, don’t bother.


I use powdered borax because it is cheap, readily available, and it
works well. I use 20 mule team powder that is supposed to be used
for laundry.

Why do people use the cone over the powdered borax, it's just
something I've been curious about. 

I worked for a jeweler who did; she had trained in England. I always
figured that was the reason. Anyone I’ve ever met who trained in the
U. S. uses powdered.



don’t use either. I use comweld silver brazing flux no 2. I find it
good for gold and silver.

What I like especially is that as you slowly and gently heat the
fluxed piece the flux becomes sticky and so when the solder is put on
it does not bounce around.

It can be mixed down with water and used as a firescale
preventative. It is also very economical a $13 jar lasts more than a

I have read the MSDS for borax and comweld they are about the same.
As with all chemicals follow the safety directions.

I only do a limited number of solders at any one time max 5. in a
well ventilated room with an extraction fan above the soldering


Most people in the US use it res a firecoat (borax powder and
alcohol) that’s why the powered form. A cone you would have to scrape
of what you want first.

Andrew Berry of uses a borax
cone exclusively. Seems that he has very good results.

Hi Elaine,

Yeah, it may be a Brit thing: I picked mine up when I was in school
in London.

Haven’t used it much since I got back to the states, except when I
couldn’t find my normal flux.

It works, but the modern fluxes are better.


Why do people use the cone over the powdered borax 

Just guessing, but maybe because it’s easy to make a paste by
rubbing it in a “borax dish” with a bit of water?

Al Balmer

I’ve been using borax cones for years, with the fireclay dish that
you grind in. You can make just as much as you want, when you want,
and there no problems with powder getting damp and clumping. I like
it also because it feels like a connection with generations of
silversmiths, and the action of grinding is quite therapeutic.


I would definitely like to try it, if I could find a supplier on
this side of the pond for both the cone and the dish.

The dish I can onlyfind in the UK, and it seems like a lot to get
one here! The cone seems like a efficient method. Powders and
pre-prepared solutions are a pain and messy".


HI again all,

Err. Just exactly what are we talking about here? Bob is the third or
fourth person I’ve seen talking about powders and ‘pre-prepared

What do you guys think a borax cone and slate are for?

They’re just an old way of making up soldering flux. I have no idea
what anybody would do with powdered borax in regards a soldering
flux, and the ‘pre-prepared’ stuff is otherwise known as–flux.
Nothing fancy. Could be batterns, pripps, or paste flux, all of
which work better than pure borax and spit, which is what you get
from a borax cone. It works, and it’s cheap and indestructible, but
it’s not spectacular or anything. (Yes, I realize that most people
keep boric acid powder around for making fire-coat, but pure borax
wouldn’t do that. I keep powdered borax around for a basic casting
flux, but again, not a soldering flux.) I’ve still got my borax
slate from college days, and I pull it out every blue moon or three,
when a student gets a yen to try it, but then it goes back into the
drawer until the next time.


The dish I can onlyfind in the UK 

Otto Frei has them for $22.

Al Balmer

I bought and used the borax cone and dish when I started making
jewellery. Unfortunately, borax alone does not prevent against
firestain. I changed to mixing my own Prips flux. It works so much
better than borax alone. I ground up my borax cone to use as one of
the Prips ingredients. I now use my dish tocut my solder pallions
into, and that’s where they stay until used. I mixedup a fresh batch
I Prips a couple of weeks ago and it is infinitely superior to the
tired, repeatedly diluted Prips I had mixed up about two years


Why the cone" That is how it was sold over a century and a half ago.
Why in preference to borax powder" well it takes up less space and I
used to keep my cone on a refactory dish and added a few drops of
water, ground the cone into it a bit and whn I had the right
consistency I usedit The remainer dried and stayed where it was. With
powder you have a lerger container to decant the powder from and the
dust gets up your nose, into cuts and eyes and is a pain when it
does. Also, you still have tomix it with water somewhere and then
fiddle about to get the right consistency and when the excess dries
out it is a sod to dissolve/grind downagain without the cone to do it
with. The powdered borax often contains other borates that are added
but the cone used to contain borax as precipitated which although not
pure had a consistency between brands which is not the case with the
others so if you buy say, Agrotect it is different from Auflux etc.
and use the wrong one and you can get firestain. Nick Royall

Well borax cones are for sale, as is borax powder, just curious to
see if there was something “magic” I hadn’t been aware of. CIA

I am sure that there are very good new and efficient fluxes on the
market. But in my case, almost everything I have ever soldered
during my 52 years career has been fluxed using a borax cone and my
old borax dish. It works, it’s cheap and a borax cone lasts for ages,
so I say to myself why change an old reliable method that works fine
for me.

Peace and good health to all.
James Miller FIPG

I have no idea what anybody would do with powdered borax in regards
a soldering flux, 

I use powdered borax as one of the ingredients when making Prips
flux. I’m certainly not going to buy the commercially available
version of Prips as it’s so expensive! The first time I made it, I
crushed up my borax cone in a pestle and mortar as I knew I would
not be using it again in cone form. UnlessI am wrong, Prips works as
a good firecoat but can also be used as a soldering flux. It works
for me.


I buy all ingredients necessary for making Prips (borax, boric acid
and trisodium phosphate) from suppliers selling via the auction site
whose name shall not be mentioned. Lab grade chemicals are available
inexpensively from many suppliers on the auction site.


I’ve always used a borax cone (~40 years). You don’t need any
special plate: just a flat piece of matte (sandblasted) glass. Or a
plain old piece of marble (it gets slightly concave over time, like
a plate). And a little bottle of distilled water. A few drops of
water, and a circular motion of the cone on the glass/marble/slate.
The more circles, the thicker the flux. I like it because you make
the flux as you need it, so it’s always clean, and you can make it
thick or thin. The old ethnic jewelers in Israel all used cones
(except for powdered solder mixed with powdered borax for filigree),
and a pigeon feather for a borax brush. Torches were used with foot
bellows and a can of benzine (petroleum naphtha).

I believe the cone borax has a higher melting point than most (all?)
powdered borax/flux. That was good for me, as I rarely use anything
other than Hard (silver and gold) solder. You might need the
powdered fluxes for Easy silver and gold solders.

Janet in Jerusalem