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Investment to fill holes in cuttlefish

Some of my cuttlefish have deep holes in the middle of the inside making it difficult to carve a clean design. I was wondering what others do about this? Is it possible to fill the holes with investment, dry and carve. I will try this but if anyone has experience and advice it would be appreciated.

I always thought that part of the charm of cuttlefish casting was the texture it gave, which would be lost if you filled in the holes…pretty cheap stuff, isn’t it? So would it be better to use one that was unblemished? Just sayin’… -royjohn

I agree but all of the ones I bought seem to have holes. The holes aren’t that wide, but are very deep. I also love the texture of the cuttlefish but I don’t think the investment will be noticed because the holes are not big enough. They are big enough though to throw off a design. I think I will need a syringe to fill the holes.

I have to speak to this. I know that we jewelers love texture, love finding ways for working with interesting materials to express ourselves. Please know that when someone mentions “cuttlefish” or “cuttlebone” they are talking about the unique internal shell that controlled the buoyancy of what was a profoundly interesting and mesmerizingly beautiful living creature. Cuttlefish can change their color, shape, and texture in ways unmatched in the animal kingdom. They have an advanced nervous system and are intelligent and curious creatures. I don’t see how anyone who considers themselves interested in the inner lives of animals, and the wonders and mysteries of the natural world, can use these cephalopods in good conscience. If you do a quick YouTube search, you can see these wildly wonderful creatures in action! I hope you will, and will think of them as valuable living beings and find an alternative to using them in your artwork.

It is my understanding that they are harvested for food and the shell is discarded. So to me it is a respectful way of repurposeing something that would just go into the landfill or to some birdcage anyway. Why not make it into art, unless you are vegan and that is another discussion altogether.

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I would ask for the same thoughtfulness to the people who eat them…

Getting back to the original issue, I don’t think pouring plaster-based investment into the cuttlefish bone is a great idea. The bone, being porous, will suck the water out of the investment before the plaster’s had a chance to set, leading to a weak patch. Also, the plaster contains chemically-entrained water, which can react explosively when contacted by molten metal. You could fire the patched bone in a kiln to burnout temperatures to avoid this problem, but if you’re going through all that, why mess with the cuttlebone in the first place? The main thing it has going for it is that it allows you to cast a rough form directly into a material that makes it easy to excavate a mold cavity. Some surface artifacts are to be expected. If you don’t like them, file them off. If dealing with animal products bothers you, try tufa casting:

Thanks. That is the kind of knowledge i was looking for before trying this. Sounds like it isn’t safe so i won’t be doing it. The holes are too deep to sand so i will just freeform an abstract design to incorporate the holes. Appreciate the technical advice.

You might consider filling the holes with petrabond or delft clay, both of which are used for sand casting so should be safe to use with the cuttle fish.


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