This topic contains 2 replies, has 2 voices, and was last updated by Clinton Gallagher @tapABILITIES 7 months ago.
- March 15, 2017 at 6:56 am #8296
I’m looking for advice on how best to cast a large amount of clear resin into a block (about 1.5 liters)
– is there a resin product that can be cast all in one pour?
– is there a rule of thumb amount of resin that one should not pour more of in one go?
– or is it better to cast in stages, letting each layer become jelly consistency before pouring the next layer (ive heard around 15min until jelly consistency)
– my main concern is that you will be able to see the layers of resin if it’s poured in stages (my goal is for it to look like a solid clear block)
– my other concern is that it will crack or break between layers once cured…
The mold I will make for this block will be made from plywood
– should I coat the plywood in anything prior to casting, aside from the mold release?
also would love suggestions on products you guys like for this sort of thing, I was thinking of using
this product: Environmental Technology 128-Ounce Kit Casting’ Craft Casting Epoxy, Clear
and this mold release: MG Chemicals Non-Silicone Epoxy Mold Release, 12.3 oz Aerosol
Thank you all so much in advance!! I’m very new to casting so all advice will mean a lot! 🙂March 15, 2017 at 3:40 pm #8302
Every resin is different. Manufacturers should be able to give you recommendations on how much of their specific resin you can mix and pour at once. Pot times (stage to jelly) also varies from resin to resin. This is a link detailing all this information on the resins we sell: https://www.resinobsession.com/wp-content/uploads/2017/02/resin-choices-jan-2016.pdf
You can definitely cast in stages. By waiting until a layer starts to gel, the next layer should not be visible, versus if you wait for the previous layer to completely cure. As long as your casting isn’t getting too hot, cracking shouldn’t be a problem.
You will definitely need a mold release if you are using plywood as your mold box. I’m not familiar with the one you have listed, but this is the one I would use: https://shop.resinobsession.com/collections/tools-and-supplies/products/petrolease-non-silicone-food-grade-mold-release
For a casting this size, I also don’t think the Castin’ Craft EasyCast epoxy is a good choice. Even when fully cured, it is still soft (you can dent it with your fingernail), and it may cure with a slight amber tint. Instead I would recommend either the Resin Obsession super clear resin or the TotalCast resin. Both can be found here: https://shop.resinobsession.com/collections/resin The super clear resin works great for molds, but you will only be able to mix and pour 3 ounces at a time. With the TotalCast, you can mix larger quantities at once, but the pot time is shorter. The shortened pot time tends to be a challenge for beginners.
I realize you likely have more questions. I’m here to help. 🙂March 17, 2017 at 3:24 pm #8340
Clinton Gallagher @tapABILITIES
I would not recommend using plywood as a form if the surface of the form that touches the epoxy is the plyqood itself; even if a release is applied. Even the smoothest surface of the highest quality finish grade plywood has minute imperfections that will transfer to the surface of the epoxy.
Secondly, 1.5 liters only describes the volume when a sound recommendation requires the height, length and width of the mold. Furthermore, a mold has inside corners to be concerned about and their shape or surface imperfections will also transfer to the epoxy.
To get the highest quality result the mold for the pour should be made of silicone. What to use as a form to make the silicone mold will be tricky. If something with a perfectly smooth surface and perfect sharp corners can be found that will be as close as possible to the finished cast epoy result that should be used and then removed from the silicone mold leaving perfect inside corners and surfaces without blemish that WILL otherwise show up on the epoxy.
Build the mold to pour the silicone into using foamcore. It has a perfect impervious surface that can be coated with release. Foamcore is used by professionals. Again though what to place into the foamcore mold to pour the silicone around remains a tricky mystery; often an existing object like a plastic tissue box or something made that has the perfect corners. Any material can be coated with release for a silicone mold.
Finally, I would build a small prototype silicone mold before going large to perfect the choice of my materials.
Good luck with it