Talk Composites - The Forum for Advanced Composites

How to achieve a shiny finish using 3D printed mould

http://www.talkcomposites.com/Topic33278.aspx

By paulsavage - 7/11/2019 4:05:24 PM

I have printed a mould in PETG to try and make a 5mm thick disc the size of a dinner plate. The mould consists of a top and bottom sandwiching the clear epoxy resin to be cast. I have sanded the surfaces of the mould right down to 3000 grit, so they are quite smooth, but I can't get a really good shiny finish. My transparent GlassCast 10 castings are not see-through, having a frosted appearance. My question is: is there something that I can coat the mould surfaces with that will give me a shiny finish, and hence a totally transparent casting, but will not bind the mould parts to the resin? I have tried the Easy-Lease Chemical Release agent and the Meguiar's #8 Mirror Glaze Release Wax, but still get a frosted surface. Applying an additional coat of epoxy resin after the casting has cured does make the surface more transparent, but its blurry, not at all like looking through a pane of glass, for example. Any thoughts?
By paulsavage - 7/12/2019 9:05:40 AM

Warren (Staff) - 7/12/2019 8:30:07 AM
It is not always possible to get a high gloss off some plastics.  You could try coating the mould with an epoxy such as our XCR resin then sand it perfectly smooth and polish to a gloss.  The gloss mould should then give gloss parts.  Alternatively just polish the parts out the mould.


Thanks for the info Warren. If I coated the mould with XCR resin would it not bond to the casting resin?