Hello Marcie,
Thank you for your forum suggestion! I have just joined “Grains of
Glass” and look forward to learning and contributing to that forum as
well!
Best Regards,
Julie
Hello Tam,
Thanks for the advice again! I am concurrently struggling with the
"final finishing of the enamel". aside from the cracks!..(sigh)
Best Regards,
Julie
Hello Kim,
Thank you for your reply! Yes, I now think my enamel was too thick.
and/ or the enamel and metal thicknesses were too different. and
perhaps my layers were each too thick as well
(this was a mens signet ring, not hollowed out, 1mm thick bezel
walls, 1.01mm recess, 5.5mm base below enamel that was not uniform.
ie: the shoulders connected to the shank were thicker than the center
of the fingerhole.
.probably not a good idea for a first enameling project, especially
in a sterling silver casting! But, my husband wanted his dragon ring!
I am going to revise the model to have a thinner recess, and recast,
and retry to enamel.
I am contemplating costing in Argentium. does anyone here have
experience in casting and enameling on Argentium?
I was wondering if the firescale-proof nature was only skin deep, or
through out the metal?
I was wondering if the firescale-proof nature was only skin deep, or
through out the metal?
Ie: if I pre-polish and polish the casting, will I have to refresh
the surface to have the germanium.? I thought I read that
somewhere.
Any help is greatly appreciated!
Best Regards,
Julie
Julie-Your recess is much too deep. Keep it no more than 0.5mm.
Needless to say (although I will!) make sure the recessed surface is
porosity free, clean, and anneal it several times using a fresh
pickle to remove all traces of surface oxidization.
Good luck.
Kim
Hello Kim,
Hi! Yes, that is the general consensus, so I will be revising my 3D
model to reduce the depth.
I am thinking about hollowing out underneath as well, to make the
"base" for the enamel a uniform thickness. although it will be
thicker at the sides/ shoulders of the shank where the top
transitions into the shank.
Also pondering if I should “try” to have it cast in Argentium
960.since I will be using opaque enamels. I got some interesting
email responses back from Argentium that I will share on a separate
post.
Either that, or back to sterling silver.
I recently called Thompson enamels, and Tom shared the following
guidelines regarding enameling sterling silver castings:
He said there were 5 important things to consider:
-
properly designed casting
-
need uniform thickness
-
thicker metal expands slower
-
thinner metal expands faster
- need a starting and stopping place for enamel
- depression should be about .30 to .50 mm in depth (will reduce my
depression)
-
need walls to be 90 degree, perpendicular to surface
-
need to tumble piece in magnetic tumbler to reduce porosity
(I hope I understood him correctly and that the above is correct!
Let me know if I am in error!)
Best Regards,
Julie
Julie-
I agree with everything but for two points;
-
tumbling does not remove porosity. Welding does and burnishing
may work if these are fine pores. -
I found Argentum to be a sub-standard alloy for enameling.
Experiment ona sheet of Argentum and one of silver and you’ll find
out for yourself.
Good luck.
Julie,
Its pretty obvious why the enamel is cracking, its because the metal
is moving on cooling in a way that is opposite to the way the enamel
is cooling.
So how do you find a solution? If i had this problem, and I did
enamelling as an income for 7 yrs, id do some CONTROLL trials, Can
you do this Julie?
-
do you have a pyrometer on your kiln?
-
is it thermostatically controlled to the desired temeperature?
-
set the kiln to the Thompson reccomended temp.
-
take some std sterlintg sheet say, 1/2mm thick, by 1in sq and
dust with a tea strainer the enamel onto it.
5 fire till it goes glossy and note the temp. examine results. did
it crack? or not?
- repeat with another piece identical, fire then refire with
counter enamel. Did it crack? or not?
7.grind off flat then re fire to flash.
-
run under hot water then cold repeat. Ie thermal movement. Did it
crack? or not. -
if you find its standing up to this treatment, then it has to be
the design of your cast ring thats at fault. -
Only you know if your up to redesigning the ring to get your
enamelling to work. There are many here who would know how to do
this.
Good experimenting. Its NOT luck its know how.
Ted.
Hi Ted,
Thank you for your detailed reply, I really appreciate it!
I will do testing as you recommend and learn more about my kiln and
enameling.
Best Regards,
Julie
Hey Julie.
How did this Enamel on signet ring turn out for you?
Doing the same at the moment, and im really interested how eveyting worked out and what you findings were!
Just did on on sterling silver… 3 pretty thick layers… And cracks he he! So very interesting thread so far!