The black scale is due to the copper, a dirty metal to cast and
weld. We found that a small bead blast cabinet worked VERY WELL to
remove any investment on jewelry castings.
I’d love to find an easier way to remove investment from castings.
My ultrasonic never seems to get off all of it. I get really tired of
standing over a bucket picking out investment with dental picks. I’ve
never worked with bead blasting. Doesn’t that remove some of the
detail from the castings?
Not really. We used a VERY small bead size and used it on pewter,
silver, bronze and gold. The beads do not remove metal but actually
peen the surface. If one dwells for a long period of time on one
spot, metal will be moved/removed but if just a bit of care is used,
there is no problem.
I use a water pressure washer first, even on delicate stuff. I do
agree that a bead blaster is a boon if you have to get scale off
bronze.It is a good idea to keep as much muck as you can out of your
blast cabinet.
Pressure washers are very cheap now, one wil pay for itsself in time
saved remarkably quickly, it will cut your clean up time from an hour
to two minutes.
I have a large old plastic tank outside on its side, the machine
lives indoors with the pipe and gun outside. Fixed to the bottom of
the tank is a sheet of wood with a lot of long nails poking up
through it, ( think hedgehog) you can then hook your complete sprue
onto it and spray from a distance and then adjust to move the
remaining plaster covered sections to face front.
You can remove detail with a bead blaster, it just depends how long
you go on…
While bead blasting will certainly clean investment off castings
very nicely, unless you have a HEPA filter on the cabinet, it will
also blow that investment into the air for you to breathe, not a
good scenario.
Water blasting is much cleaner and safer, you can use either a gun
like Rio and other jewelry suppliers sell, a pressure washer like
you’d get at the hardware store or what I use, a Mystic spot
cleaning gun, bought it on ebay. They are essential for cleaning
milled waxes if you do any CAD too.
Glass bead blasting is the best way to clean your gold and silver
castings with out damaging it.
Two types of glass bead blasting can be used dry as well as wet. I
am using wet bead blasting since 1992 for my gold and silver
castings.
I prefer wet glass bead blasting since there is no dust generated
and water provides a cushioning between the glass beads and casting
surface and the cleaning is of surgical quality. The surface after
wet bead blasting is clean surface which shows the defects in the
castings if any clearly.So the wet or dry glass beads blasting can
also be used as a quality control step.
I clean the wet glass beads regularly of the investment build up, so
the casting surface remains shining and not mat.But Mat surface is
some time good for some designs if no polishing is required.
Test your castings with wet as well as dry glass bead blasting, if
the jewelery tools supplier provides this test before buying the wet
or dry glass beads blaster.
Investing in a wet glass bead blaster will really prove beneficial
in long run and you will be happy as I am.
May all be free of ill will, animosity, anger, hatred.
May all develop goodwill and love, peace and harmony.
May all be Happy and liberated.