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How to remove shellac?


#1

This can be a very easy manoeuvre, put the item(s) into a small jar
with alcohol or a.k.a. “Methyl Hydrate, 99.9% pure”. You can buy this
solution at any “Home Depot” store. Let it sit there for an hour…but
this takes too long,right?

For a faster process, put that same jar in a sieve and then place
that sieve (with the jar of alcohol) and let it be suspended into a
ultra-sonic cleaner…and in less than five minutes.

…viola! All is cleaned!..“Thou shall not use this process on
Emeralds, or Opals.”

It’s even faster if the solution of the sonic-cleaner is warmed up
prior to this cleaning process, why? Note for all=> ‘Alcohol’ works
faster to remove the shellac if the tank temperature is warmed up…

Gerry!


#2
For a faster process, put that same jar in a sieve and then place
that sieve (with the jar of alcohol) and let it be suspended into
a ultra-sonic cleaner..and in less than five minutes. 

Gerry and everyone,

Just for safety. When combining heat and ultrasonic action to a
flammable liquid extra precautions are needed for ventilation.
Normal vaporization rate of alcohol doesn’t pose to much of a problem
in a normal shop setup, but heat and ultrasonic increases
substantially, the rate of vaporization of the alcohol, so some added
ventilation is called for. It could be possible to vaporize so
rapidly that an explosive solution with air is made before it can be
diluted with ventilation.

Dan Culver


#3

Dan Culver, here is a further note from my last posting! Oh you are
so right, I found that I have to loosen the lid of the jar while in
the sonic-machine. The highly agitated solution, continually gives
off vapours. But here is the important point, I never heat up the
solution to “hot”, only to “warm to touch”! As I don’t use any form
of flames at my setting bench, the chance of fire is non-existent. I
keep my solutions in a separate room!

Gerry!


#4
As I don't use any form of flames at my setting bench, the chance
of fire is non-existent. I keep my solutions in a separate room! 

The ultrasonic is not a intrinsically safe device so it can possibly
generate sparks that can ignite the vapors, There are a myriad of
ignition sources beyond open flames, you might want to keep that in
mind.

Jim

James Binnion
James Binnion Metal Arts


#5

Dear all,

My instructor Ray Grobe taught me to remove shellac by placing the
item in a baby food jar with denatured alcohol in it to cover the
piece. Placing the jar into the nozzle of the steamer slowly and
carefully add steam. I mean SLOWLY. This will heat the solution and
remove the shellac. Too much too quick, and you have a mess on your
hands. Kind of like an espresso machine makes a late’. I would hold
the jar with a towel or cloth because it does get hot. It takes a
little while to dissolve the shellac, but everything to do it is
readily available in the shop.

This is one more old world technique I did not make up and am
confidant was done carefully. I have done it many times myself with
success.

Best regards,

Todd Hawkinson
www.southeastmn.edu/jewelry


#6

Just in case Todd’s description isn’t clear, it’s important that you
totally immerse the nozzle of the steamer in the liquid. In fact, it
works best when you press the tip of the nozzle down to the bottom of
the jar, in the center, not to the side. And you need to have enough
liquid so the nozzle is immersed several inches. Be sure to step very
lightly on the pedal, so only a little steam is released. If you hit
it full blast, or if the nozzle isn’t far enough under the liquid,
then you’ll blast the entire jar’s worth of liquid, and perhaps your
jewelry item too, out of the jar. Not nice. If your steamer is one
with a solenoid valve that’s either full on or off, so you can’t
control the amount of steam, you may have to experiment to find how
much liquid needs to be there for this to work. It may take something
larger than a baby food jar.

I use this method routinely at my work, to heat plain water, such as
when I need a little quick boiling water to make up a little liver of
sulphur solution. For mea, a 600 ml beaker about 1/3 to 1/2 full of
water works well for this, and if that’s more water than I need, I
pour off the excess after steaming. But I’d confess that I’d be a bit
leery of doing this with anything more reactive than water. Alcohol?
Maybe. But be sure to wear safety glasses just in case (good advice
doing this with water too.)

I first learned to use the steamer to boil water many decades ago,
back when I was still kinda foolish (these days, I pretend to have
learned some wisdom and caution…). We’d put about a cup of water in
a quart pitcher, put in gold jewelry needing cleaning, add a half
teaspoon or so of potassium cyanide powder, boil the solution with
the steamer, then pour in a “glug” or so of concentrated (30%)
hydrogen peroxide. The pitcher had to be angled and low in the sink
so when the result “burst”, sort of a soft slow explosion, the liquid
ejected from the pitcher stayed in the sink. This process, called
bombing, really shouldn’t be done this way, without proper fume and
waste control (properly, it should be done in a fume hood, with the
means to collect and process the waste liquids). And we were just
running the liquid down the drain. Not good. Most of the cyanide gets
converted to safer (but not totally safe) cyanate compounds, but
remaining cyanide residues in the waste water was probably illegal,
and throwing away the dissolved gold, even at the then much lower
gold prices, was just a waste. But it sure put a pretty bright gold
finish on the jewelry… (and gave me a bit of a headache
sometimes… No doubt killing brain cells…)

In my home shop now, I simply bought a little cheap microwave (one
of those black friday deals at Target. Something like 30 bucks…)
that sits next to the steamer. Much safer. It also can safely heat up
plating solutions (just don’t use this microwave for food). And a
nice little magnetic tumbler totally eliminates the need to bomb
things, as it gets into almost as many details, and does so more
reliably on more metals than bombing works on.

And frankly, rather than directly heating the alcohol to remove
shellac, I’d suggest simply using your ultrasonic cleaner. Get a
small strainer basket that you can set across the cleaner, that will
support your alcohol jar about halfway immersed in the cleaner. The
ultrasonic action will warm up the alcohol reasonably quickly even
if your cleaner isn’t itself heated. Takes a little longer perhaps
than boiling the alcohol with steam, but not by all that much. The
advantage is simply that you’re not then risking blasting a bunch of
alcohol in your face, or filling the room with alcohol fumes.

Peter


#7

People, I don’t know why everyone is so concerned with heating the
denatured alcohol to remove shellac. Just soak it in a baby food jar
and give it about an hour or so and it will be fine, COLD! Been doing
it for 24 years and so far… no problems!

Steve Arista Designs LLC