Is Sun and Heat OK for my 3D Resin Print?

Can you leave your 3D Resin print sitting out in the sun? Won’t that melt it? The short answer is that no, your resin print won’t melt in the sun–at least not one that’s printed in Simon’s Strengthening Solution! In fact, for a few hours at least, your resin print will be perfectly fine! They can even survive sitting in a hot car without any issues. How do I know this? I took a bunch of our 3D resin printed werewolves outside to enjoy the summer weather, and everyone came back safe and sound (and they didn’t even have to apply sunscreen!).

The Volunteers

Meet our volunteers! These werewolves were designed by 3DsofSan and are eager to get out of the magic shoppe and see the world! They are going to spend the day at various locations around the house and then will come back to visit their brother, a lazy sot named Control, who will be spending his day in the cool, shaded closet where our minis wait for someone to adopt them.

The Locations

Our adventurous werewolves found spots both in and out of the sun and heat to enjoy their day out. Werewolf 1 checked out the BBQ in full sun. Werewolf 2 chilled on the back porch, in the shade. Werewolf 3 and 4 tried to figure out how cars work, with 3 ultimately giving up and lounging on the seat in the shade while number 4 sat up on the dash and enjoyed all the heat and sun that a 108 degree California summer day had to offer. Finally, Werewolf 5 was feeling a little less adventurous and stayed indoors, though he did sit in a south-facing window all day and enjoyed plenty of sun.

The Method

I placed the Werewolves in their locations at 10am and checked on them hourly. I took their temperatures using this handy thermometer and checked to make sure no one was melting, cracking, or catching on fire. Unfortunately (fortunately?) nothing exciting happened. No one even melted even a teeny bit! Werewolf 4, up on the car dashboard in the sun, reached the highest surface temperature of the day, checking in at 157 degrees F (69 C) at 2:00pm. He felt fine and frisky, as did his brothers. After 5:00pm the sun had shifted enough that some of the wolves who started in the sun were no longer soaking up any rays, and I terminated the experiment.

As you can see, all the Werewolves look great. A couple of the ones from the sun look slightly lighter in color, but the difference is so slight it’s hard to tell for sure.

The Results

You don’t need to worry about leaving your 3D Printed Resin Mini in the car on a hot day. It will be fine. Cured resin handles sunlight and heat without a problem.

But…

3D Resin Printing works by using exposing liquid resin to UV light which hardens it. By building up thin layers of hardened resin, the printer eventually produces a finished figure. After cleaning, the figures are given a final curing of concentrated UV light to make sure the resin is completely set and safe to handle (liquid photosensitive resin is toxic). For a material that reacts so strongly to UV light, it seems odd that sitting out all day in the stuff would have so little impact on the figures. So I decided to try and break them.

Drop Test

When testing out Simon’s Strengthening Solution, our proprietary resin blend, I dropped our miniatures from various heights onto a hard tile floor to see what sort of damage they suffered. I did that again with the werewolves from the sun experiment. Keep in mind that they all spent the night inside, so they were all the same temperature when they were dropped.

I found that a day in the sun doesn’t have the much effect on how breakable your figures are. Only two of the werewolves suffered any damage from being dropped from a height of 6 feet. While both of those DID spend the day in the sun (Werewolf 4 was on the car dashboard all day and Werewolf 5 sat in the window) they suffered very minor damage. Sunlight may make your Resin print more brittle, but not by much (at least, not when they’re printed in Simon’s Strengthening Solution!).

Further Tesing

What about long term exposure to sun and heat? Or how about exposure to variations in heat that come from being outside all day and all night? Meet Sunny (previously known as Werewolf 1) who spent his day out monitoring the BBQ in full sun. He liked his adventure so much, he’s decided to become our new BBQ mascot and stay outside for awhile to see if there’s any long-term effects of sun exposure. We’ll keep an eye on him and will let you know if he starts to develop a sun burn.

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Update January 2023

It’s been 4 months, and Sunny is still enjoying the outdoors. We’ve had some heavy storms here in California and Sunny has learned about cold and rain. He might need a bath, but otherwise he’s doing fine.

Update August 2023: One Year Later

A year of exposure hasn’t damaged Sunny a bit! He’s made friends with some spiders, it looks like. And is that mold?? Sunny, take a bath all ready!

Update April 2024 (18 months later)

Sunny is still doing just fine! He has made some new friends.

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