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Enamel on Platinum


#1

I’ve been told that hard fired enamel will not adhere to platinum. Is
this true or false? If false, is there any special procedure that
must be taken to carry it out. I have customers who want white gold
enameled and we can do it, but need to alloy (18K) with palladium.
Palladium being $800-1,200 per oz. over the past months makes for a
very expensive material cost. What do those in the know have to say
about this? Jim Mannella www.uniqueandprecious.com
Lake Worth Fla.


#2

Years ago, I tried to enamel palladium/ruthenium I learned that
enamel wouldn’t stick, because the palladium oxidized at about the
same temperature as the enamel fused that the twain refused to
neet.Platinum and nickel white gold will work. As will yeallow gold
that may be rhodium plated later.


#3

Hi, It is my understanding that it is true. The reason, platinum does
not oxidize. Apparently what keeps enamel sticking to the metal after
melting is the oxide layer created on the metal during heating that
diffuses into it. Yes, even gold has an oxide layer when heated,
although it is thin. The expansion coefficients for each of the two
materials are also likely to be incompatible.

Source of infornmd ation. Glass on Metal. Sorry, don’t know which
volume and number.

David


#4

Palladium has been selling for under $800.00 an ounce for a little
while now. In my latest invoice from a major casting house the price
difference per pennyweight of 18 K palladium white gold vs.
traditional white gold is $2.00 per pennyweight ($14.71 vs $12.71
respectively). So, I wouldn’t say that it is an overly expensive
material, especially since 90/10 iridium/platinum is going for almost
$41.00/dwt.

The real cost of using palladium alloys is hidden. Refiners do not
pay out well for the palladium in your scrap. Some pay out 50% of
the market value, others will only return the metal to you after it
is refined. Make sure you figure this in the cost of your
manufacturing.

Still, it is important to remember that most gold alloys are not a
straight gold/palladium mix. Other metals are combined including
metals such as silver and copper. So, an ounce of 18K pw will have
much less than a quarter ounce of palladium. For this reason I would
assume that 14 Kpw would be relatively more costly that 18 Kpw since
there is proportionally more alloy to gold in the mix.

Larry Seiger


#5

HI! No, enamel will not stick to platinum. When I was doing a lot
of Plique-'a-jour I had a large sheet of heavy platinum foil which I
formed and used to back curved pieces for the first several firings,
then all I had to to was to peel it off and could use the foil again,
over and over. Pat DIACCA Topp


#6
HI!  No, enamel will not stick to platinum.

I suspect that it depends on what type of project one is doing. I
recently enameled some engraving in a platinum pinky ring. Worked fine
for me.


#7

Hi Rod,

I’m making a poor paraphrase of it, but some scientist once commented
that the most beautiful ships of theory often sink on a little reef
of a fact. Your “exception” to the rule has prodded my curiosity into
thinking that there is something to be learned here if you are
willing to share some more details with us.

What comes to mind, for example, is how deep was the engraved portion
relative to the area engraved; in other words did you enamel a bright
cut or something larger (champlev� or pit enamel)? What type (brand,
colour, transparency) of enamel did you use? Did you tourch or kiln
fire it?

Thanks for letting us know; and please keep breaking those rules for
us :wink:

David


#8

The last time that I enameled platinum, I was building a pinky ring
with “Allah” in Arabic engraved in the top. I started out the job with
a wax model that I engraved to 1/2 mm more or less. As I recall, the
was a mark similar to an apostrophe that I really couldn’t engrave
that deeply. The client was an actual princess from Jordan Very
particular. We worked together for a couple of hours to get the
lettering just exactly so. Trimming and touching up with gravers. I
used a torch and #1995 black enamel from Thompson enamels. At no time
was I under any impression that it might not work. If anything, I was
afraid that the client would drive me over the edge. When all was
over, she had delivered to me a 3lb box of Godiva and it was good.

I mentioned that I tried to enamel palladium and it failed. Palladium
has a period during heating when it oxidizes. I believe that it is a
range between 900-1300F or so. It has been a really long time since I
studied this. Above this temperature, the palladium will give up it’s
oxides. On this particular job, my mentor wanted a plate embedded in
a field of enamel to set diamonds. He preferred setting in palladium
over white gold, which I think that most of us can relqate to. My
experience was that the palladium had a tendency to bead up.
Overheating didn’t overcome the problem. I eventually
made the top from white gold.


#9

You have to experiment. We have successfully enameled on pt900 with
glass gloss black enamel. Before we tried I checked with others and
was told that it could not be done. There is so much mis information
(myths) regarding procedures in our field it is pathetic.

I am still waiting for someone to write a fully detailed accurate
book on the complete casting process.

Art


#10

Help!! Has anyone fired enamel on Platinum with sucess? I knew I was
letting myself in on a gamble, but I didn`t expect it that bad…
Platinum as far as I know does not expand when heated. Is there an
enamel that works on Platinum? I am using opak coulors on little
shapes nothing very difficult. It works on gold and white gold, but
it cracks on Platinum. My coloures are from Schauer and Milton Bridge
Please if anyone has good experience give me a hint.

Thank you
Ortwin


#11

I use a platinum sheet to fire plique a jour enamels on BECAUSE the
enamel doesn’t stick to it! Tony Konrath


#12
    Help!! Has anyone fired enamel on Platinum with success? 

I have not personally fired on platinum, but according to the
Thompson Enamel Workbook: “Thompson’s Medium Temperature-Low
Expansion enamels fired at 1450 degrees F and their High
Temperature-Medium Expansion enamels fired at 1600 degrees F work
very well on platinum”.

We do carry Thompson unleaded enamels, please contact us off line.

May you always enamel with passion in your heart

Joan Schlaifer
Schlaifer’s Enameling Supplies
1441 Huntington Dr. PMB 1700
South Pasadena, CA 91030
(800) 525-5959 (626) 441-1127
http://www.enameling.com


#13

It sounds as if the Coefficients of Expansion of the enamels you’re
using are too high mate - try Thompson Enamel Company’s Medium
Temperature-Low expansion enamels fired at about 1450 deg F or their
High Temperature-Medium Expansion enamels fired at about 1600 deg F.

Al Heywood


#14

Low expansion enamels are the way to go- I recently finished a
commission with a platinum pendant that had a small recess that had
to be enameled. We ended up using an enamel from Thompson’s and had
no problems with cracking.


#15

I have had a customer who needed to enamel on Platinum and did it
sucessfully using Thompsons 1995 black, she tried many colours and
companies and found this to be the only one to work sucessfully,
hope you didn’t need any other colours