FYI or Frequent asked Questions about metal clay.
Rings are one of the coolest things you can make with silver-clay. Here is how I do it when I have the finger!
Wrap a piece of paper around the finger of interest. carefully mark the diameter of the finger on the paper. unroll the paper and using math or an enlarging photo-copier add 13% (for pmc3 fired to 1200 F and held for 20 min)
Then find something, a dowel, mandrel, stick and wrap tape around it till it matches the paper with the added 13%!
another method involves Investment
A mix that requires 35% water. Example: to 100 grams of investment use 35 grams of water, or use approx. 2 Tablespoons investment, to 2.5 teaspoons of water. Sets in 6-8 Minutes. Dry before using.
To make a Ring Form wrap a piece of paper around the finger needing a ring, carefully tape it so it holds its shape. Place paper ring on a smooth surface and fill with investment mix. +Allow a day to dry. Make a ring larger than the investment finger you have made, place the larger ring (two sizes) on the cylinder and fire! Investment washes out under water after firing:
Build the ring make sure the joints are strong, overlap, score and slip the joints.
This from Rio Grande…
Question Does firing time alter shrinkage?
Process Make five identical rings from PMC3™. Fire them at 1650˚F (900˚C) at different times, then make careful measurements.
Sample 1 15 min.
Sample 2 30 min.
Sample 3 45 min.
Sample 4 60 min.
Sample 5 120 min.
Results The rings were exactly the same.
Conclusions Firing PMC3 for 15 minutes at 1650˚F creates a dense material. All the binder is gone and the silver particles are well joined. Prolonged heating does not add to density.
Question Does firing temperature affect shrinkage?
Process Make five identical rings of PMC3™. Fire them at different rates and carefully measure the results.
Results The rings were smaller as the temperature increased.
Conclusions As predicted, lower temperatures do not fully fuse the metal, leaving a material with microscopic spaces. At higher temperatures the metal becomes denser, as seen in smaller rings. This “densification” could be described as more shrinkage.
temp ˚F hold time final diameter % shrinkage
Sample 1 1110˚ 45 min. 19.0 mm 11.7
Sample 2 1200˚ 20 min. 18.7 mm 13.0
Sample 3 1290˚ 10 min. 18.5 mm 14.0
Sample 4 1450˚ 30 min. 18.0 mm 16.3
Sample 5 1650˚ 30 min. 18.0 mm 16.3
Shrinkage numbers are confusing, and relate not only to the type of PMC® and firing temperatures, but also to the size and shape of the piece. All stated shrinkage rates refer to fully sintered PMC, and should be thought of as plus or minus 3%.
Hi there. Could you please explain to me what the difference is between Accent Gold for Silver and Aura 22? Thanks!
Accent gold is a product that was developed by a Scientist (Ron Diegle) here in Albuquerque NM, It is 24k or pure gold premixed in a bottle (1 gram). The Aura22 is 22k, so a less gold color, it was developed by Mitsubishi in Japan. It is also a 1 gram bottle with a little vial of thinner to be used if needed. The aura22 may brush on a little smoother. Application, drying and firing is very important with these products and effects how happy the end user is, they are not idiot-proofed. I think the accent gold shows up better and has a nicer color.
Shipping overseas.... International
We love shipping anywhere in the world via US Postal service Global Express, place your order in the cart We will contact you by e-mail for your approval of the shipping amount. We will verify your credit card by the billing address you give us to protect you against stolen cards. We only ship using UPS, or US post office Global express as these are all trackable. Our other web site www.nmclay.com has even more products and also allows you to preview your USPS Global Express shipping charges. Sorry Art Clay cannot be sold overseas.
Can PMC and/or Silver Art Clay be made into a slip and brushed onto bisque and still retain it's beauty? thanks.....Maria
Yes! On low fired porous bisque, thin the slips a little so the brushstrokes don’t show and paint on 2-3 coats. You can then adhere other hand made silver-clay items to the slip. Fire to the temp recommended for the clay you are using but SLOWLY, use a rate of 450F max.
On porcelain or over a glaze you must use Art Clay Silver's Overlay Paste.
Eleanor asks...stove top firing really work?
Yes i have used it many times and it is featured in art clay classes.
Are the pieces strong? Yes bring them to red heat for ten to 20 min.
Can a kiln used for other purposes, like glass, be used with PMC? of course!
Is there any adverse effect on the kiln? no.
Is any special cleaning required? not at all.
Does PMC have to come up to temperature or can it be put in a hot kiln?
it can but it must be very dry. what is the hurry?
Thanks so much for your help. I love this stuff and will buy lots.
More on firing...
Hi All, Is it possible to effectively fire pmc 650 on a burner from a gas BBQ grill outdoors maybe at night? I have an old grill that is past repairing but the side burner is like new. Hate to waste it. Thanks, Diane ...
Yes grills work great, wherever there is a flame you can fire pmc3. See Firing for full instructions
Why two brands?
Hello, I'm from Germany and I took a lesson in Art Clay Silver. Now I found your internet site and I'm a little bit confused. What's the difference between PMC and Silver Art Clay. Nelly
Like Coke and Pepsi, two different brands. Both companies Aieda and Mitsubishi have Japanese patents on silver-clay. Most clay types are similar but, Art clay sells a slow dry version and PMC has it's original that shrinks a lot.
From: Christine: Can the Sentry express 3.00 digital controller be installed on any kiln? Can I buy this and put it on my 240volt kiln for ceramics? I do fused glass and art clay. Thanks
You can buy a digital controller for your kiln, however they are expensive, follow the link below to see the Skutt controller for a 48 amp 240v kiln. A smaller kiln would use a less expensive controller.
Dried up Silver-clay
I have PMC (Fine Silver Clay) that has never been used but is about 5 or 6 years old and of course dry. How can I use this now? I know it can be refired so there must be a way. Appreciate your help. Thanks, Meryl
Here is Tim McCreight's answer from the PMC Guild website.
A: PMC is made of particles of precious metal, an organic binder, and water. The precious metal and the binder stay the same, but it's possible for the water to evaporate over time, even though the PMC has never been opened. If, when you open the box, the PMC is stiff and hard to form, it simply needs more water.
I've successfully re-hydrated PMC that had dried out rock-hard. It's easy to do: open the box and hold the lump of PMC under running water for a few seconds so its surface gets totally wet. Rewrap it in cellophane and set it aside overnight, periodically kneading the lump through the cellophane. The goal is to get the moisture into the PMC. This takes time because it is a very dense material. Unwrap and test the PMC: you should be able to flatten it into a disk without cracks appearing at the edges. If it's still too stiff, wet and rewrap it again and let it sit longer. Two treatments are usually enough, but you may continue until the PMC returns to its original, soft, workable consistency.
Also you can grind the clay up in a spice grinder or pepper grinder into a fine powder, then slowly add water drop by drop allowing time for the moisture to absorb.
Trish Asked Can you use both PMC and Art Clay on the same piece?
Yes you can, just make sure that you fire to the highest temp required by the type of clay you are using. So if you use PMC original with Art Clay650 slip you have to fire to 1650F and hold for two hours.
Can Art Clay and PMC be mixed?
Yes always fire to the higher temp required by the clays.
Can all of the forms of Art Clay be fired at 1650? Will they be stronger, as in PMC?
Yes after (or during ) firing art clay and PMC are .999 silver so they have the same properties.
What do you do if after you have fired something at 1650 and want to add a stone or a dichroic cabochon with PMC3?
The PMC3 slip will adhere to fired PMC. Will it adhere on its own with slip or do you have to use something else. Art Clay Oil Paste will work even better, or you could paint Art Clay's overlay paste on the cab and then slip that to an existing piece. The overlay paste will adhere to glass.
Do you add this right after the firing or do you polish it first and then add the cabochon?
I would not polish as it will make the silver less likely to adhere.Firing
Lynne asks Please let me know whether the Art Clay or PMC Starter Kits Include the torch. It doesn’t mention it, however does state Everything you need to get started making, firing .....
No to the torch, you can use a gas stove or a BBQ with a side burner. We cannot ship torch fuel through UPS so you would have to go buy it anyway. You can go to home depot and get an inexpensive propane torch for plumbing $14.00 including fuel. I think this is the easiest way. Of course you can get smaller butane torches for cooking creme brûlée but they tend to cost more. Firing is not difficult.
Rubina asks .....Can PMC original be fired with a torch instead of a kiln?
Maybe you could but you would have to do it for two hours!
Q. How do you fire Art Clay Silver in a cone sitter kiln?
Low fire clay fires to 1200 F which corresponds to cone 019-020, the highest recommended firing temperature of all silver is 1650F or cone 010-011. Ceramic kilns fire much slower than jewelry kilns so the actual hold time is not too important.
For PMC3 or ArtClay 650 fast fire to cone 017 no hold time needed. (Fire on High until the cone turns off). let cool as long as you can wait.
For regular art clay or PMC+ use cone 014. 011 is the hottest possible cone for the most durable item. (Actually if your rate is 585F in the last 200 degrees then cone 020 works out to 1201F if you want to get technical) but we need a no hold time temp to fire to. Don’t try to fire PMC original if you have no way to hold for 2 hours.
Place the silver-clay on a kiln washed shelf right under the cone setter. That way the cone is measuring the temp right at the silver-clay. All of these suggestions relate to computerized kilns too if you cant figure out the ramp and hold programming. Don’t worry about the cost of firing a large kiln it is about $1.00 per hour.
Place the Silver-Clay near the cone sitter or thermocouple, on a shelf, use Alumina Hydrate to support the piece if it seems like it needs it.
Deborah H asks Can PMC/Art Clay be applied and formed over a lead weight- or other less precious heavy metal, and then fired?
The only one i have heard of is using fine silver as a backing, most other metals tarnish in the kiln. The other problem is that dissimilar metals don't like to be bonded and are likely to corrode. Stainless steel may work, you try it and let me know. Of course the lead or tin would melt before the silver was fired.
Can other metal components be incorporated into designs using the silver clay as a plate?
Fine silver and 24 K gold will work for sure, sterling sort of works, I bet stainless will work, you cant fire anything with copper in it except in a sagar full of charcoal.
Sandy Asks... I want to work with the metal clays to go around my fusion glass pieces and..My question is will glass melt into the metal?
It will if you fire over the sagging temp of the glass.
& do I make the metal piece 1st and then glue on the glass, or the other way around?
You could but we don't like glue, better to make a mechanical connection.
( Can the glass be finished (fused) and then go back in the kiln with the metal? )
That is the most common way. fuse the glass at 1425F and then fire the PMC3 to 1200F and the glass will not be effected.
Heather R. Responds
Comment: Hi - I was reading your FYI page and wanted to make a correction. I am a glass artist. I fired PMC in my glass kiln directly on the treated shelf - for more than one full year, I had silver fuming on the plates (particularly reds and blacks) that I fired on that area of the kiln shelf. The silver stays in the shelf (apparently) and fires out over a very long time. What I do now, is turn the smallest shelf over to fire the PMC. Then turn it back over for glass. So far this has worked for me. Thought you should know...
Thanks for the first hand info, We believe it is the lead in the glass reacting with the silver. Bullseye sells a lead free clear that doesn’t pick up the silver.
Ivanna asks, I would like to know if I can embed the Sacagawea coin's in PMC gold or silver ???
No, only real precious metals can be fired, the dollar is not made of anything valuable. Make a bezel 10% larger and then mount the coin after firing and polishing.
We keep getting bubbles in our piece when we torch fire the piece - what are we doing wrong or how can we avoid this effect? Help! Thanks. C
Your clay is not dry. Try these recommendations. Drying Time
- Hair dryer (1200w) At least 10-15 minute 10cm/4 inches from the piece.
- Cooking plate At least 7-10 minutes at 150~180/300-330o F
- Electric kiln At least 7-10 minutes at 150/300o F
- Natural dry At least 24 hours at room temperature.
Little Ceramic hot pot
Hi! Thank you for providing a forum for questions! I am having an issue with some of the pieces I make, I am hoping you can help me. I fire my pieces in the Little Ceramic hot pot that uses gel fuel. I can fire 2 pieces at once and 1 piece will be perfect, the second will have areas on the back that remain a powder. I thought that maybe I had too many pieces in the pot , so I have tried firing one at a time. I still get these weird areas where the PMC3 has not become solid metal. I use a wire brush and brush like crazy and eventually get to metal. The back of the piece ends up with dips and gauges. What am I doing wrong? I hope you can help! Thanks, Marilyn.
The manufacturer says to
1. Only fire one piece centered on the grate
2. Fill the pot almost to the top with the napalm
3. Make sure the hot pot is not in a windy or breezy place. Perhaps in a large box, outside or maybe on your kitchen stove with the exhaust fan on full blast, with a window cracked open.
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