Resin not hardening

We have the problem that the black resin (v2) isn’t hardening properly. Here is a picture of a piece which was more than 3 hours in the Formlabs Form Cure and as you can see the surface is still liquip/sticky in most parts. Even the supportbase is still a bit sticky.


How can we avoid this? How can we ahrden the prints?


It looks to me like the resin is hardening perfectly, otherwise you wouldn’t have such a nice clean print. Perhaps you need more washing in IPA to remove the surface resin, is your IPA old and saturated would be my first guess?
If you really need to cure the outer face, then you need to remove oxygen from the surface, because it inhibits the reaction. Some people have achieved this by putting parts in water in the UV lamp.

Hope that helps.

Thanks, for the hint. I immediately tried some underwater curing, put it didn’t improve. The surface is still almost liquid, e.g. my finger leave prints:


The IPA can’t be the prolem either, because it is fresh.

How long are you leaving the parts in IPA ?`Are you shaking them a bit while they are in ?

I’m leaving Standard resins at least 5 mins in one bath and 5 min in the other, but that’s because I am using compressed air after each bath to blow off the resin. Without compressed air 10min in each bath is the recommended time, less than that and especially if you don’t agitate the parts it is likely that a thin film of resin may remain on the parts.

Alternatively and for models with lots of nooks and crannies a very soft and fine brush works well (brush while inside the resin bath). Others have reported successes by using a small airbrush like the ones used for model making, and putting IPA instead of paint.

I did print the models again and did brush them a bit before putting them into the From Cure. And now the are perfect. Thanks for the help!


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