[Adam Pollock]

We were asked to embed small pieces in a clear polished resin dome. They are looking for a standard ‘bell jar’ display shape like a glass dome 6in diameter by 12in tall. A straight cylinder with a dome at the top. The kind of jar you would use over display item like a delicate swiss clock or a butterfly display.
I am wondering if we can just buy a glass piece and then use polyester resin directly into the glass so that the glass is both the mold and the final encasement. Then we wouldn’t have to create a mold and try and polish the piece we cast. It would just be ‘done’ and glass on the outside, suspended objects in the inside encapsulated in resin and hopefully clear as glass through and through (presuming we don’t get bubbles). I would cast upside down. Pour a partial layer in to about 4inches, then pre-wet the items being embedded, pour additional resin and place the objects. Then mix a final batch to fill the volume. So I have a couple of questions:

1. Will the exothermic reaction crack the glass (will the resin expand cracking the glass?)
2. Which resin should I use?
3. How much resin will I need?
4. If my embedments are at 4 inches from the inverted bottom of the dome will I see seams in the different layers of resin I need to pour in? What change in hardener would I be looking at adding (I saw your note about modifying the amount of hardner in larger castings and if you have a prior layer setting up when you pour the new layer down.

Your response is so greatly appreciated! I am a bit intimidated by this project.

[Katherine Swift]

Hi Adam,

All great questions! I will answer them with corresponding numbers:

1. Yes, it may, especially with polyester resin.
2. You mention polyester resin. Do you have experience with polyester? It’s not something I recommend for beginners and not my first choice in this case since it sounds like you won’t be polishing the final product.
3. We have a resin calculator to help you figure out how much resin you need.
4. If you pour your next layer when your first layer is starting to gel, and not completely cured, you will minimize the lines between layers. You do not want to modify the amount of hardener you are using for subsequent layers unless you use a polyester resin.

[Adam Pollock]

Thank you for your answer Katherine. I do not have experience casting. What resin do you recommend for this project as described, if not Polyester?

[Katherine Swift]

If it were me, I would use the Resin Obsession super clear resin for this project. You can find it in several sizes in our store here: https://shop.resinobsession.com/collections/resin/resin-obsession

This FAQ on the resin answers additional questions you may have: https://www.resinobsession.com/resin-frequently-asked-questions/resin-obsession-super-clear-resin-faq/

[Adam Pollock]

Thank you Katherine. I will explore this suggestion.

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