Resin questions (adhesives, UV resistance, and food safety)

Support & Troubleshooting
1

Hi all,

I am getting great results from my new Form 2 so far, but I have a few questions about the various resins that I haven’t found answers to so far.

  • I’ve read a bunch of advice about assembling parts with either a bit of uncured resin and a UV laser pointer (which is a great idea!) and CA adhesives, but does anyone have advice for adhering different resins together (particularly adhering Tough to Flexible)?
  • Which resin is most resistant to long term UV exposure (outdoor use in direct sunlight)?
  • Are any of the standard resins food safe? I figure the Dental resin must be close, but I can’t tell for sure from the MSDS sheets.

Thanks in advance for any advice!

2

Hah. I’m planning to run this very experiment, Flexible and Tough. Also, Tough and Clear. FL technical support actually suggested it to me. You can bond two different resins together with either resin and a UV light/laser.

There’s a white paper on curing someplace on the FL website. It includes data on how “overcuring” affects material properties of the different resins. I think the general consensus is that if you intend the print to be exposed to UV after printing and curing, it’s best to paint it with something that blocks UV.

None are food safe except possibly the Dental resin. Though how durable those parts are, I don’t know. But printed parts still smell of resin even months after printing. That’s “Volatile Outgassing” and whatever it is that’s gassing out will just as readily mix with liquids (= food) instead of air.

I agree the MSDS is fairly “benign”. But I think if you ask FL they will caution you in the strongest possible way not to use printed parts for food, don’t put prints in your mouth, and don’t use them for body piercings (if you’re in to that sort of thing :slight_smile:).

3

In addition to Randy’s informative answers, here’s where you can find the post-curing data and access the whitepaper: formlabs.com/support/finishing/post-curing-prints/

I’ll +1 the point that resins are not food safe; exempting Dental SG’s biocompatible certification, resins are not tested or certified for be in contact with any consumable.

4

Thanks for the info! I figured food safety was a stretch, but the dental resin got me curious. For outdoor exposure, I guess it’s time to start practicing my rattle can skills.

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