How can I know whether a mold will make shiny pieces or not?
You can easily identify which molds will give you shiny results and which ones won't.
If the mold has a shiny inside, then the results from that mold will also be shiny. A mold that has a shiny inside will look as follows.
This is how the results from that mold will look like
On the other hand, if the mold has a dull/matte inside, then the results from that mold will also be dull/matte. For example these molds has a matte inside, which looks like so.
The results from a matte mold are as follows.
When working with resin, you can easily make your non-shiny resin pieces shiny by doming them with resin. It is an extra step but it's totally worth it because the results are amazing. In the video below I show how easy it is to dome your pieces to make them shiny. In the video I use UV resin but you can also use epoxy resin.