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Fine grit carborundum grain for soldering

Does anyone know where to find fine-grit carborundum grain for
soldering? I’m having the hardest time finding a supplier.

My first experience with it (which was most pleasurable indeed) was
during my apprenticeship with a local jeweler, where I fell IN LOVE
with the stuff. She had a very small stash of it which she guards
carefully because she, too, can’t seem to find a source to
replenish what she has.

I read (via Wikipedia (usual Wikipedia disclaimer applies…)) that
"It occurs in nature as the extremely rare mineral moissanite (SiC
aka silicon carbide)." Given its rarity, might that be why I’m not
finding it in this form? --But then that kind of doesn’t compute
because, as with many other rare minerals, its use is consistently
widespread in everything else from general industry abrasives, to car
brakes, electronics and more.

So, any known sources of the stuff? Anybody want to share their
stash? (I will pay.) --I also wouldn’t mind having/finding one of
those small cups/holders that you use it in…

Tamra Gentry


Silicon Carbide is commonly used for tumbling stones. You can get it
anywhere they sell grit for tumbling stones. Here is but one

Since I doubt you need a 50 pound bag I would suggest something like
the Lortone Tumbling Kit that has several different grades of grit
so you can pick and choose.

If you are in a hurry, an auto parts store will probably stock it or
be able to get it in short order. It is used in garages inside
sandblasting cabinets for grit cleaning parts (Lasts longer and cuts
better than sand). A final local possibility is the yellow pages
under sandblasting, call around and find who does grit blasting with
silicon carbide grit and see if they will give or sell you a pound if
you bring your own container (They buy it in 50 and 80 pound bags)


Note From Ganoksin Staff:
Looking for a sandblasting cabinet for your jewelry projects? We recommend:

not sure what fine-grit carborundum grain is, but silicon carbide is
used in lapidary. You can get silicon carbide abrasive from 30 grit
to 1000 grit. one source is Kingsley North

hope this helps

Does anyone know where to find fine-grit carborundum grain for
soldering? I'm having the hardest time finding a supplier. 

Any lapidary supply company. One of the best for price is Johnson
Brothers Lapidary, just Goggle it.

Richard Hart G.G.
Denver, Co.

If that is what they call soldering grains, I got some from Rio a
while ago. Haven’t used it much, because I use mostly paste solder
and if the piece tips into it, as it sometimes does, the grains stick
to the paste solder.

Janet Kofoed

Does anyone know where to find fine-grit carborundum grain for
soldering? I'm having the hardest time finding a supplier. 

Carborundum is manufactured by the ton. It has about the same
relation to moissanite as carbon black does to diamond. However, it
seems to be hard to find as grit, but you can get sanding and
polishing paper or film in an auto supply store. You can contact

and see if they know where to get it retail.

What’s the actual use? Would alumina work? Most lapidary suppliers
have that in various grits.

Al Balmer
Pine City, NY

Any lapidary supply will have it by the pound or ton. It’s rare in
nature but not in industry. It’s common and cheap, in fact. Look to
Rio Grande in their lapidary section…

How do you use carborundum grain in soldering?

Jerry in Kodiak

What in the world do you use it for? Is it the same as the fine
silicon carbide we use for tumbling grit?

Does anyone know where to find fine-grit carborundum grain for
soldering? I'm having the hardest time finding a supplier. 

Try a lapidary supply such as Kingsley North

They have silicon carbide medium ranging from 30 to 1000 graded
grit, costing from $3 to $5 a pound. I’m not a lapidary, nor have I
ever used the grit in soldering, but I have thought about it several
times. Good luck, and please let us know how it works for you.

SiC, carborundum, seems to be available in a number of grits on ebay
at around $10/pound, and I assume many lapidary suppliers. Are you
sure it is carborundum and not corundum? I have seen corundum used as
a solder support, but I would guess that with the higher thermal
conductivity, SiC may work better as a hear sink.


Check Otto Frei’s soldering section on their site. They sell a
"black soldering grain" and you can get a pound for $6.


Rio carries silicon carbide soldering grain around $13 for 32 oz.

Karla from sunny southern California anxiously awaiting the solar
eclipse later today.

Carborundum grit is used is lithography printmaking to progressively
grind the stone. It is available for printmaking/lithography
suppliers in a variety of grades from 80 to 320… don’t know
whether this is fine enough for your purposes though. One supplier I
found via a Google search in the US is, they list
#320 carborundum grit for $5.75 per 1lb. under Litho Stone Graining /
Levigation Abrasive Supplies.

Heather L (in Australia)

Rio Grande has fine SiC soldering grain:

Metalliferous has courser SiC grains:

Contenti carries what they call emery grain:

Elliot Nesterman

Hi all,

Thank you for the replies and both on and off-forum.

@Bob and Jerry: --With regard to soldering, using carborundum grain
is almost like sticking something in sand to hold it in place. I
prefer to use it instead of a third hand for certain things that
need to be held upright or at a particular angle, etc. --It’s an
"anchoring medium," I guess.

BTW, maybe I shouldn’t have said “fine grit” because what we worked
with is slightly more coarse in size, and I can imagine that I don’t
want it to be too terribly fine anyway. --I slapped the “fine grit"
label on it because it is pretty doggoned fine in comparison to the
much larger pumice “pebbles” I have in my pumice pan (I’m not a fan
of pumice for smaller stuff…) Anyway, we used it in a small (maybe
3-4” diameter) bowl (I’m not sure what material the bowl was made
of) that lent itself very well to being able to keep things upright
when you’re using a tiny flame to do precision work. I don’t think
it was too much of a heat-sink, as I never had any problems using
it–that is to say, I don’t feel as if I had to use more intense
heat or extra flame-on time to get any given job done. --It seems to
work well for silver, gold, platinum, different combinations of
mokume gane, etc.

@Marlin: You know, I’m not sure whether it’s caborundum or corundum
grain–I understand why you ask–I think that at one point I may
have even searched for both. I’m pretty sure the lady I worked with
said carborundum–but I’ll have to double check with her. She got it
so long ago though (15+ years, I think), that I’m willing to bet she
may not remember.

I <3 the Orchid Forum. --To the rescue yet again! Thank you!


Hi Tamara. I think I got mine from Allcraft in New York, but I’m not


It amazes me that this stuff appears to be all over the place, but
my specific search strings on Google turned up little to nothing!
::blushing/embarrassed:: [And why the heck didn’t I think to check
the jewelry suppliers first? Oooops! --I guess I probably figured
that if it was out there, it would turn up at whatever the source via
Google, and then I’d just click the link and voila! ;-D]

Again, though–thanks for all of the links. Now I have the dilemma
of having to choose where to buy it! --But that’s certainly much
better than having no options at all. (@Elliot Nesterman: I think the
emery grain is what I’m after–that looks about right…)

Thanks again! ::begins Peanuts-style happy dance::


I haven’t used carborundum grain as a heat sink for soldering, I
assume you add water to it. It is available at a lapidary supply
house in tumbling grit form, available in a wide range of sizes. I
use something called “garnet sand” which, I assume, is just what it
says. I have also hoarded my stash, which is almost gone. I guess
I’ll try the silicon carbide grit next.

Good luck. P. S. if you can’t find the grit, I’ll be happy to ship
some. Don Rinner.