New Clear formulation? Aesthetic/technical differences?


#1

Noticed on the website that the Clear resin doesn’t require post-curing. If my memory serves correctly, didn’t Clear resin previously used to require post-curing?

Has the formulation changed? If so, have any of the material and aesthetic properties changed?

Given it says no curing necessary, is it also fully, safely cured by the laser? Is the part as technically as strong as a post-cured part? Just wondering if not post-curing was more due to not wanting the clear piece to yellow slightly, rather than for safety… How toxic is it to handle (after being fully washed in IPA, of course) without the post-curing like it used to?

Thanks, Tímo


#2

I don’t expect the resin to be “toxic” before post-curing. TBH the uncured resin isn’t very toxic, if at all, to the skin anyway. All the warning are mostly a liability thing, as there can be symptoms of sensitivity/alergy to acrylates/methacrylates but it’s rare and harmless.

As for post curing, there is still a significant increase in mechanical properties (72% increase of tensile modulus) when post-curing for 15 min
https://support.formlabs.com/s/article/Form-Cure-Time-and-Temperature-Settings?language=en_US
The reason why I think Formlabs says post-cure isn’t necessary is because Clear resin is mostly used for non-mechanically critical applications (modeling) and as such the absense of the slight yellowing occuring during post cure is worse that the mechanical strength gained. If you don’t post-cure to avoid yellowing, I would coat the part with a UV-stabilized clear acrylic spray, otherwise the part will yellow over time due to the UV component of daylight.