Enameling on Argentium?

It was these things --the softer anneal and the extended work
time, not to mention the firescale and tarnishing resistance-- that
led me to say that in terms of it's workability Argentium is more
like, but not the same as, fine silver than it is like standard
sterling. 

Has anyone tried enameling on Argentium?

Alana Clearlake

    Has anyone tried enameling on Argentium? 

Not on Argentium, but on the hardenable silver produced by Johnson
Matthey. What I found was that enamelling hardened the metal, and it
also started a process of age hardening. This lead to the pieces
cracking 3 - 6 months after they were made, i.e. long enough after
manufacture for them to have been sold.

It may be possible that the my designs contributed to the cracking
and that, for instance counter enamelling wound have prevented the
problems. But I would be very very wary of using an alloy of this
type with out extensive and long term testing.

If any one is interest I will put some photos of the cracked pieces
on my website over the weekend.

Bill Bedford

I’ve put up a couple of photos of pieces that ere made of hardenable
silver and cracked after being enamelled. They are at:-

http://www.mousa.demon.co.uk/photos/pendant.jpg
http://www.mousa.demon.co.uk/photos/dish.jpg

Bill Bedford

I too, had the enamel pop off when the Argentium came back down to
room temperature. Tried a second time “anchoring” the enamel a bit
with an undercut around the frame and a textured surface for the
enamel to “bite”… Same result.

Brian Marshall

I've put up a couple of photos of pieces that ere made of
hardenable silver and cracked after being enamelled. .... 

Hello Bill,

I assume from your mention of “hardenable silver” that you don’t
mean Argentium, correct?

I don’t have any technical data on Argentium’s shrinkage rates but I
have heard that some “hardenable” silvers contain significant amounts
of nickel and/or magnesium and have higher than normal shrinkage
rates. Might something similar have happened to you? If you could
specify what alloy you were using that would great.

Cheers,
Trevor F.
in The City of Light

Bill it looks like the pieces were counter enameled!

How thick was the silver and how long before the cracks appeared.

Did they appear slowly and grow or did they suddenly generate.

Was there pop off with clean metal or did the enamel split?

Did the split initiate on some sort of impact?

Charles Friedman DDS
Maker of small functional enamel pieces: Teeth
Ventura by the Sea

Bill,

Just an idea. Could the spalling be the result of incompatabilities
of expansion coefficients between the glass and the metal?
Unfortunately my copy of the CRC Handbook does not list the
expansion coefficient of germamium.

One idea I would like to propose is that you make a test strip using
Thompson enamels #1020 and #1045. The expansion coefficients are
respectively 260 and 341 cm/cm/degC x 10e7 and are at the extreme
limits. #1465 has an expansion coefficient with a value of 300
cm/cm/degC x 10e7 and is halfway between the two extremes.

David

in sunny and dry Victoria, a perfect February for we humans but not
the trees

    I assume from your mention of "hardenable silver" that you
_don't_ mean Argentium, correct? 

I’ve said before it was the Johnson Matthey Hardenable alloy

    I don't have any technical data on Argentium's shrinkage rates
but I have heard that some "hardenable" silvers contain significant
amounts of nickel and/or magnesium and have higher than normal
shrinkage rates. Might something similar have happened to you? If
you could specify what alloy you were using that would great. 

This had nothing to do with shrinkage. The cracking was most likely
caused by age hardening.

Having talked to Peter Johns this morning, I am convinced that
Argentium silver will not fail in the same way. However I suggest
that there needs to be a largish corpus of work produced be fore I
am completely sure that Argentium is ‘safe’ to be used with enamel.

Bill Bedford

    Bill it looks like the pieces were counter enameled! 

They weren’t

    How thick was the silver and how long before the cracks
appeared. 

.7mm on the pendant .9mm on the dish and 3-6 months

    Did they appear slowly and grow or did they suddenly generate.

Suddenly

    Was there pop off with clean metal or did the enamel split? 

The enamel didn’t come off the metal. The metal cracked.

    Did the split initiate on some sort of impact? 

Not as far as I know.

Bill Bedford