Back to Ganoksin | FAQ | Contact

Crucible Cleaning


#1

How does one remove accummulated borax/flux from a crucible? I have
tried grinding it out or scraping it out under heat, but both of
these methods are laborious and unsatisfactory. Thanks.

Brent Glasson


#2

Get a new one? They are cheap. Recycle the old one.

Ringman


#3

Buy a new one, crucibles are “consumable items” they should be
replaced regularly to keep the junk that builds up in them out of
your melts and castings.

Jim Binnion

James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160


@James_Binnion
Member of the Better Business Bureau


#4

Hey all,

    How does one remove accummulated borax/flux from a crucible? I
have tried grinding it out or scraping it out under heat, but both
of these methods are laborious and unsatisfactory. Thanks. 

You will have the best result, though not great, by chipping away at
the built up flux with a screwdriver. Once you can break through it,
you can chip away a good portion of it. Do NOT do this without
safety glasses!!!

Another trick that sometimes works (a little) is putting used
crucibles upside down in your kiln through your overnight burnout
cycle. The flux will melt and some will run out of the dish. In the
end, however, the easiest thing to do is simply replace the crucible
with a new one. They are inexpensive enough that it should not be an
issue.

Mark Moretti
Alexandria, VA


#5

They are consumable, but you can also clean them. Throw it in the
pickle over night. Pull it out the next morning, rinse, and let dry
over two or three days. You’ll need to re-glaze it.

-Stanley Bright
A&M Jewelers
Catonsville, MD


#6
    They are consumable, but you can also clean them. Throw it in
the pickle over night. Pull it out the next morning, rinse, and let
dry over two or three days. You'll need to re-glaze it. 

While this will dissolve the flux glass it also contaminates the
crucible with metal salts and acid . Just replace them

Jim Binnion

James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160


@James_Binnion
Member of the Better Business Bureau


#7
While this will dissolve the flux glass it also contaminates the
crucible with metal salts and acid . Just replace them 

WOW!.. That’s great news… I have always ‘ut the heat to them’
… ‘dripped the glass out’…never got it real clean… So, I just
through it in a pickle solution over night??? and reglaze after a few
days of drying?? Nothing more required??

Thanks,
Jim


#8

At the risk of sounding like I don’t know what I’m talking about–
So what?? You reglaze the crucible anyway… Also, I use sparex not
acid (acid-acid) in my pickle.

-Stanley Bright
A&M Jewelers
Baltimore, MD


#9

The easiest way to clean crucible is to put few tablespoons of
boraxic acid and melt it with a torch under hood /gets smoky/ swirl
crucible with molten concoction and pour it to ingot mold, after it
cools down put this staff in to pickle or muratric acid to retrieve
any metal was stuck to crucible. It is easy ,fast ,leaves crucible
completely clean and ready for next melt right away.

Rafal
www.thorrko.com


#10

Why would you go through that when you can just pickle it all out
and dump the crucible out in the pickle pot right with any extra
metal or stones you have left? I personally don’t enjoy glazing
cricibles because of the hot, bright color and also seems like a
waste of gas/time. (Read between the lines-- you can extract melee
this way from stuff you’ll be sending to refiners.)

-Stanley Bright
A&M Jewelers
Baltimore, MD


#11

When I find that the layer of flux etc. becomes too heavy I heat the
crocible as if I was going to cast and then add a fair amount of
common table salt (sodium cloride - NaCl) and mix it carefully with
the flux. This makes the flux more fluid and makes it a lot easier to
scrape off the goofy thing with a piece of iron or titanium. Works
for me and has for many years.

Kindest
Niels Lovschal


#12
    At the risk of sounding like I don't know what I'm talking
about-- So what?? You reglaze the crucible anyway..  Also, I use
sparex  not acid (acid-acid) in my pickle. 

Because you are adding compounds that will contaminate your melts.
You want to have as little extraneous elements in your melt as
possible. The sulfer in the sparex (sodium bisulfate NaHSO4 . H2O)
will react in the melting process and produce sulfur dioxide which
will get into your metal and will produce porosity, how much will
depend on how many times you do this and how the reactions proceed
in your melt. Once you sulfur dioxide in the metal the only way to
get it out is to refine the metal. Covering it with flux will not
help as the flux will just pick it up and bring it into contact with
the metal.

BTW Sparex is an acid it is just not quite as corrosive to skin and
clothing as sulfuric or other mineral acids. Here are some synonyms
for sodium bisulfate (Sparex): Sodium hydrogen sulfate; sodium acid
sulfate; sulfuric acid, monosodium salt, monohydrate

Jim Binnion
James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160


@James_Binnion
Member of the Better Business Bureau


#13

I wasn’t aware that anything stayed in the crucible after rinsing it
and drying it. I can’t say that I’ve had porosity issues doing this
way though. I have had the gold “boil” when I was melting it one
time but I was under the imporession that I was holding the torch too
close to the gold and letting oxygen get into it. Thanks for your
suggestion. I’ll look into it.

Stanley Bright
A&M Jewelers
Baltimore, MD


#14
    I wasn't aware that anything stayed in the crucible after
rinsing it and drying it. 

Most crucibles are somewhat porous and the pickle will get into the
body of the crucible and you cannot rinse it out.

 I can't say that I've had porosity issues doing this way though. 

There are already so many variables to contend with to get excellent
castings why add a new problem when it is not necessary. My original
point was that with the relatively low cost of a crucible why not
just replace it. I use my old crucibles to melt my scrap for
refining once they are too messed up they go in the low grade scrap
barrel for future refining.

Jim Binnion

James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160


@James_Binnion
Member of the Better Business Bureau