Making Moulds: Spheres

Making Moulds: Spheres for Pearls with Transparent Silicone

Sphere Mould Making Tools

Mould making spheres is very similar to charm bead moulds but I think a little less complicated, so I’ll do a separate post for those and another one for flatbacks and cabochons. You can download or pin a printable version of our silicone types here:

silicone mould making chart free from Nikki Kamminga at Tree of Opals
silicone mould making chart free from Nikki Kamminga at Tree of Opals. Click to open then Pin or right click (Windows)/Ctrl+click (Mac) to save.
the supplies you need to set up mould masters for spheres or pearl moulds Tree of Opals Nikki Kamminga
the supplies you need to set up mould masters for spheres

To prepare your mould masters (the bit you pour the silicone into) you need a few supplies. I use 11mm
stainless steel shot but you can use 3/8in (9.5mm) or 10mm. A few mm makes a lot of difference and it’s up to you and your clients what size to go for. Anything under 8mm can be hard to work with but you could go as low as 4mm for very tiny resin pearls for earrings, which you can glue onto earring posts (they tend to be about 3mm). I recommend getting a digital calliper for high end jewellery for mould making.

pearl sizing guide, 9mm pearl compared to an 11mm pearl
pearl sizing guide, 9mm pearl compared to an 11mm pearl

You can skip a lot of the work here by cutting out little circles of double sided tape and popping the sphere directly on top but the trouble is they tend to move around, and because the silicone around the hole is very thin it can tear easily, no matter how tear resistant your silicone. I like to secure the spheres on a little platform that’s the right width and height. It’s a bit fiddly but worth the effort for a decent mould for high quality jewellery.

gold breastmilk pearl with subtle 23.5ct gold leaf encased in resin, hand wire wrapped with solid 9ct gold setting for a necklace, Tree of Opals copyright image
gold breastmilk pearl with subtle 23.5ct gold leaf encased in resin, hand wire wrapped with solid 9ct gold setting for a necklace, Tree of Opals copyright image




I find any bubbles in my resin come up into the pouring spout with a little persuasion (more on resin another day). For this you’ll need plasticine! Raid your kids’ craft stash or buy some but trust me, Playdoh won’t work. It dries out and the same goes for other mould making clay. Blu Tack is too hard to work. You could try an oven bake polymer clay like Sculpey if you have it, because it won’t dry out, but I think plasticine is a little less expensive.

sphere silicone mould ready for filling
sphere silicone mould ready for filling

Using Plasticine in Making Moulds

I take a piece of label backing, because we get through tons of it with our shipping labels and order notes. It’s totally non-stick which helps when transferring the little “dots”. Roll a piece of plasticine out about as thick as 5 playing cards. Precious metal clay artists probably have those already taped up, everyone else don’t worry about buying cards, you’ll find the perfect thickness as you go or you can just get a cheap adjustable rolling pin. Using a stainless steel hole punch you can cut out the little dots (push them out with the end of a thin paintbrush). Cut out as many as you need then prepare your 20ml plastic shot glasses (it’s really important to get the 2cl or 20ml plastic ones, especially if you’re using the expensive water clear silicone, because a 30ml container will need 10ml more resin. If you’re making 20 moulds, that would be an extra 200ml or 7oz or silicone. I prefer not to have too much silicone in my moulds because it gives me a clearer view of my silicone cast and the finished piece is easier to remove.

If you’re making larger than a 12mm pearl mould then you might need a 1oz/30ml shot glass, and for larger spheres for making orbs and paperweights my advice is to save up yogurt pots or ask on your local Freecycle. If you’re making different size spheres it can be helpful to mark them in some way. Some mould sellers, I’ve heard, mark their finished moulds with Sharpie but this quickly rubs away. When I sold moulds I liked to use a tiny bit of plasticine to press a number into the bottom of the shot glass. If you wanted you could look for little sticky foam numbers, or just use tiny dots. I used to use a single dot on the side of my own donut shaped charm moulds. Now I don’t worry because they’re the only kind I make, but we’ve just started using 11mm spheres as standard instead of 9mm and my new 11mm ones I’ve made for this blog I used a pair of pinking shears to cut the bottom so they look different to my 9mm moulds. Pinking shears are great for making cloth baby wipes and family cloth from rags and have saved me a fortune over the years…

sphere silicone mould in progress Tree of Opals Nikki Kamminga
sphere silicone mould in progress

Give your sphere a good polish with a lint-free polishing cloth like these then use a pair of long nose jewellery plies to grip it firmly, place it on the plasticine dot and without squashing it down to hard, transfer it to the shot glass.

Please see our next blog about silicone to learn how to calculate the silicone volume, weigh, mix, de-gas and pour, and how to finish the moulds off.

Using Sphere Moulds To Make Pearls

You can see my own pearl designs here and I’m happy to give anyone advice on finding their own, unique way to set their finished resin pearls but I ask you not to copy mine too closely!

ash pearl dangle charm European charm bracelet or necklace like Biagi and Pandorabracelets
ash pearl dangle charm European charm bracelet or necklace like Biagi and Pandorabracelets

I’m currently writing a series on making keepsake jewellery:
How to Make Breastmilk Jewellery
How to Make Cremation Ash Jewellery
How to Make Lock of Hair Jewellery

Please use the blog signup link below to get an email notification when we post new blogs, and please comment if you have any questions or feedback.  Feel free to share this blog far and wide including resin and jewellery making groups (with admin permission of course).

mould (UK) = mold (US) thanks for the heads up Robin! Mwahhh x
calliper (UK) = caliper (US)
jewellery (UK) = jewelry (US)

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