Polishing FL Clear Resin to Crystal Clear.... question


Been a big fan of the 3D Printed Camera made on a Formlabs including the Clear lenses.

Been trying to achieve crystal clear results on a, say… egg shaped item.

After polishing with several grits and cleaning up, I pour resin on top of the egg and it becomes clear instantly. Now the big question is:

HOW DO I CURE the liquid resin without messing fingerprints / gloveprints / whatever to a crystal finish?

I tried exposing it to the Sun but after 2h its still very sticky. It’s just a matter of repeating sunbaths over and over? I understand Sun will be faster than any UV machine? Or am I wrong?

Any other tips or tricks?


Did you see the post on creating camera lenses with SLA?

For the resin dipping in that post, the lenses were left on support bracing so that they wouldn’t need to be handled themselves.

As far as curing goes, a UV box is going to be much quicker than sunlight. Both light and heat initiate the curing process which is why we developed Form Cure. On a budget, a small cure box can be rigged which should still prove much quicker than leaving parts out in the sun.

Thanks for the prompt reply!

Yes I saw that article, thats the one that took me to try the technique! I just also saw the Times Square giantic lens you set up! AMAZING!!! I’m speechless!!

So the problem I have then is that there’s lot of support that needs to be sanded and of course polished and coated clear afterwards…

I’ guess I’ll have to set up a tiny rig system like 4 needles holding the egg on the air or something haha!!

THanks for the tip on the cure! I just finished converting a sterilizer onto a much more efficient UV cure unit :wink:

I’ll throw it in then.

That time square lens was a render :slight_smile: I walked into our photo studio while they were shooting some of the photos for that and a few of them were done by overlaying a miniature version of the lens atop a 4K TV. We have quite a few printers here at HQ dedicated to printing out the segments and it’ll be exciting to see it all come together in February.

One technique that you might use for the lens is to fully support your object and then remove all but a few exterior bracing supports after printing. If you polish down the supported area a bit, you should be able to use resin dipping and brace the object with a few remaining exterior support structures. You could also remove all of the supports and then glue tiny pegs or needles to the exterior like you mentioned.

Let us know how it turns out!

Yeah, you need something to hold stable easily. I did a windshield piece for a model and the only way to get it clear was to sand it very carefully, tried the dipping technique but the part was complex enough that I couldn’t get the coat even on the part. If you want to sand it, then you need to really take the time and do a full smoothing with each level of grit.