Silicone 40A resin is advertised as 100% pure silicone with no monomers or acrylates. Could someone help me fill in my mental model of how this works? Are there RTV silicons out there that are UV-cured? What gets dissolved in the 80% IPA : 20% n-Butyl Acetate post-processing step, and does it get dissolved just from areas near the surface or does the solvent penetrate the whole part?
Also, how does the material hold up to saltwater and petroleum oils? (e.g. when used as a gasket)
I assume since it’s not advised to use this material where it gets exposed long-term to UV, that outdoor use isn’t recommended. Any mitigations (like a coating?) aside from covering the part?
Thanks!
1 Like
Formlabs Silicone 40A resin is a pure silicone material and not a hybrid with other polymers. Formlabs Silicone 40A resin does not contain any acrylic or polyurethane that are commonly used in 3D printing resins. The 100% Silicone claim refers to the polymer composition of Formlabs Silicone 40A resin.
As far as the washing: largely it is dissolving the monomers (silicone monomers are still monomers) and helping it to come off of the part. Over time it does begin to penetrate the whole part, which is why we don’t recommend excessively long wash times. We do recommend ultrasonic washing for Silicone in particular though, because a lot of the washing action is actually a mechanical action of wiping away the resin with the solvent.
As far as chemical compatibility and UV, both are actually on the TDS. The salt water resistance is pretty good, nothing was majorly absorbed, but some oils will definitely get absorbed into the silicone, causing it to swell and soften. Depending on the exact choice, this may vary, but I’d definitely advise caution. UV aging you are correct, outdoor use will definitely degrade it pretty rapidly. There are UV resistant coatings out there, I’m not super familiar with flexible ones, but I’m sure they exist.
1 Like
This is very helpful, thanks!
2 Likes