Resin Types - imyownyear/Z-Butt GitHub Wiki

Opaque vs clear

Opaque resins are a great way to get started with casting. While most resins will retain a lot of bubbles from mixing, opaque resins can generally hide most of them internally if you do not yet have a pressure chamber.

Opaque resins that we recommend:

  • Smooth-Cast 300 series
  • Alumilite White - Amazing Casting Resin

Clear resins however, almost always require a pressure chamber or vacuum setup. They can be more difficult to use for this reason, but are well worth the effort for the ability to match colors as well as have transparent keycaps.

Clear resins that we recommend:

  • Smooth-Cast 325 series (not 100% clear, they have a slight amber tint to them)
  • Alumilite Clear
  • Alumilite Water Clear
  • Alumilite Amazing Clear Cast
  • Epoxacast 690

Polyurethane vs epoxy

Polyurethane resins are some of the most common, and what we would generally recommend for most use cases. However, epoxy, while significantly thicker, can be used for petri effects that urethane resins are too thin to support. Epoxy generally takes longer to cure, but depending on what you're looking to do would be a good choice. The longer cure time also allows for more bubbles to escape if you're not using pressure or a vacuum when casting.

Yellowing

An unfortunate side effect of clear resins is they will yellow when exposed to the sun. How long it takes depends on the type of resin. Smooth Cast 325 will yellow within days, Alumilite takes years for a noticeable effect. This is something you really only have to be aware of if you're doing encaps or petri.

Pot life and Cure times

Pot life is how long you can expect your resin to stay in a pourable state before it hardens too much. Your pot life and cure time can vary wildly from what the instructions for your resin say, due to keycaps using such a small amount of resin. Expect most resins to have a similar pot life, but longer cure time than what's advertised. Note that the ambient temperature of where you are casting will affect this as well. Hotter climates can expect shorter pot life and cure times.

Pot Life

  • Smooth-Cast 300 - 5 minutes
  • Smooth-Cast 325 - 3 minutes
  • Alumilite Clear - 8 minutes
  • Alumilite white Amazing Casting Resin - 8 minutes
  • Amazing Clear Cast - 40 minutes

Cure Time

  • Smooth-Cast 300 - 10 minutes for demold
  • Smooth-Cast 325 - 30 minutes for demold
  • Alumilite Clear - 90 minutes (May want longer, as the keycaps will still be very vulnerable to fingerprints and squishing)