Best coating choice for waterproofing SLA transparent resin?

[cjwalsh]

Hi! I'm printing a transparent part in SLA resin (via a service -- not printing it myself) and it will live submerged under a few inches of fresh water. I've been researching trying to decide which coating would be best to use... I've come across suggestions for FlexSeal, PlastiDip, clear acrylic spray, and epoxy coatings. Is there one that would be the most durable/reliable? Or a different, better option? The part needs to remain transparent after coating. It's part of a lighting effect, so the finish should also be glossy/smooth, i.e. not matte. Thanks for any tips!

[cjwalsh]

Just following up on my own post -- I got MG Chemicals clear epoxy because they thought it should bond OK; it seems to, but it's a little more viscous than I hoped, and more importantly it doesn't easily wet the very smooth SLA plastic, even when lightly sanded, so I don't think I'll use it going forward. (West said their epoxy may not bond well with the SLA resin so I didn't try that.) I read that clear acrylic sprays probably aren't a great idea for this application. FlexSeal seems like it would be way too thick. PlastiDip -- don't know? I'm kind of at a loss for a product that might work here. But in good news the SLA resin (Somos Watershed XC 11122) is apparently quite resistant to water to begin with, so the coating may not really be necessary. I guess only time will tell.