Jesmonite shell and starfish dish with glitter chips

I tested two ways of inserting glitter chips. The first was to leave the chips in, then quickly sand the surface of the shell once the dish was unmolded. However, I found that the gold came off as I sanded, revealing a transparent material. For the second method, I put in a lot more chips, even if it meant having an irregular edge on the dish where the chips accumulated. Personally, I find the second option much more successful, and it's the one I recommend to achieve the starfish geode effect. Slide a good quantity of potato chips into the areas where you want them to appear. Note that only the chips in direct contact with the Jesmonite will be attached to the cup.

Prepare the jesmonite. I recommend using a scale for more precise measurements. Use a cardboard cup, a stainless steel bowl or a small glass jar that you won't reuse for cooking, only for DIY. For the shell cup, mix 30g of AC100 liquid with 75g of powder. For the starfish dish, mix 50 gr liquid with 125 gr powder. Other types of Jesmonite may require a different ratio.

Mix quickly to obtain a homogeneous liquid paste. Jesmonite starts to harden after 5 minutes, so add your colorants quickly. For the gray starfish, I added 10 drops of black. The white shell contains no pigment.

Pour the mixture into the mold, pushing it into the mold with a spatula. You can see where Jesmonite is missing through the silicone mold. Pinch the edges of the molds and nooks to try and squeeze out the trapped air. Don't fill all the way to the top of the mold, as this will leave a large area to be sanded afterwards. Then tap the mold for several minutes to remove all the air bubbles. Leave to harden for 2 hours before unmolding. Don't wait 24 hours before doing so, as this will make sanding very difficult.

Take your time unmolding, then sand down the mark left by the mold entrance with a finer and finer grit. I recommend sanding with water. This involves soaking the sanding paper in water to remove dust as you go. If you wish, you can varnish your piece.