Making a Silver Replica from a Bone Pendant

Custom requests are when I have the most fun. In this particular case, it was extra fun because I was making my husband’s anniversary gift!

He already owned a Hei Matau pendant made out of bone and wanted it in silver. Since  bone is very fragile, I couldn’t make a mold “the regular way”. Normally I would use silicone rubber and make a mold using a vulcanizer. However, in this case, the vulcanizer’s heat would have pulverized the bone and ruined the mold. For this reason I had to use a special two-part resin mold that cures at room temperature.

Here is how I did it:

1. I applied Super Glue to the bottom of the bone pendant (hei matau) and attached it on a brass sprue.

bone hook on frame

2. Took two aluminum plates and covered the frame. Placed two small clasps on each side to hold the frames tightly.

frames

3. Mixed the resin and the catalyst according to the manufacturer’s instructions. After mixing I placed the compound in the vacuum and removed as many bubbles as I could. Even after vacuuming, the sucker  had TONS of bubbles I couldn’t remove!

two part mold

4. Poured mixture in the frame until it covered the piece.  You can see the bubbles I couldn’t get rid of! Urgh!! I set it aside and waited 16 hours for the mold to cure at room temperature.

silicone poured in frame

5. Removed mold from the aluminum frame and cut it open with an exxacto knife. Took the pendant out and examined the mold. You can see all the bubbles that didn’t come out at the top of the mold. Here’s when I started freaking out.  By some miracle from above, none of the bubbles touched my mold! wohoo! Thank you Jesus!

mold cut open

6. Injected the mold with wax 5 times. Hubby gave me the green light to produce more than just his gift. So 4 of these babies will be up for sale soon! Woot!

wax injection

7. Then I made a wax tree out of the wax models that I was casting in silver. Notice the green anchor? That’s another custom order!

wax sprue

8. Filled the flask with investment, placed it in the steam dewaxer for 1 hour. Once the timer was done I put it in the hot kiln and  waited patiently for the 5hr burnout process to be completed.

steam dewaxer, kiln and spincaster

9. After a loooong burnout process the wax melts and the investment hardens leaving and empty cavity in the shape of the wax models. This cavity is then ready to be filled with melted silver using a centrifugal casting machine. I put the flask in the spincaster and melt the silver. Then when the silver is liquid, I let the casting machine spin and the centrifugal force shoots the melted silver in the flask filling out the cavities. So awesome.

using the spincaster

10. After submerging the scolding hot flask in water, the investment dissolves and the cast silver pieces come out with ease. They are black from oxidation and, to remove it, I put them in an environmentally safe pickling solution until they turn white. Cut out each piece with the jeweler’s saw and keep the scrap silver for future pieces. Nothing is wasted.

silver tree

11.  File, sand and polish the piece. Here I am polishing the pendant.

polishing silver

12. Clean in the piece in the ultrasonic and done! Phew!  Casi que no! Happy anniversary!

finished silver hei matau pendant1

always with love,

Adriana

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Making a Mold

Thanks to my dad, I am a huge Star Wars fan. I remember him bringing the betamax movies home and watching them all day long. Today, I don’t watch them as much, but I still love the characters especially the Storm Trooper.

Since my husband also likes the movies I decided to make him a Storm Trooper pendant to wear with a leather necklace. I liked the end result so much that I needed to make more. I didn’t wan’t to do all the melting, pouring, rolling, cutting, soldering, filing, sanding, and polishing all over again (especially for multiple pieces) so, to make my life easier, I made a mold. Let me show you how.

1. First, gather the basics. Silicone mold rubber material, aluminum frame and plates, brass sprue, and your piece of jewelry.

I like this one, it feels like silly putty.

2. Cut two layers of silicone, and insert them one at a time inside the frame until you have filled it to the middle. Press the sprue in the center edge, making sure it touches the frame. Press the pendant into the silicone rubber and also make sure it makes contact with the sprue.

3. Cut two more layers of the silicone and place them on top of the piece, making sure every corner is covered. Add the top aluminum plate and place it in the Vulcanizer for 1 hour 15 minutes at 300 degrees F.  It’s 15 minutes per layer, but I always leave it a little longer.

waiting…

4. Let it cool. Open the frame, take the mold out and cut it open with an X-acto knife.

mold cut in half

5. Inject the mold with injection wax, as many times as you want to replicate your item.

wax injection model

6. That’s it! It’s ready for casting. The time it takes me to make 20 pieces using this technique is the same time it would take me to make just one piece from scratch!

prototype and wax model

Molds can last many years. Proper storage in a well ventilated area will preserve your molds for over 30 years. Neat huh?

It takes a lot to make hand made jewelry.  🙂

AWL