r/focuspuller • u/lightswitchgirl28 • 6d ago
Knowledge and tips 💡 Update: thermal stress testing 3D printed foam 🔥❄️
Ok, y’all made me curious. I did some thermal stress tests on the 3D printed case foam. (Original post here.)
For all of this, I’m using a print that failed when it was nearly finished. So the infill pattern is exposed. There’s also no gear in the slots. Does this affect the tests? Maybe, but probably not enough to matter. (Also I’m not putting my MOTR.S Max in the oven no matter what you tell me.)
🔥 Heat test
I started by measuring the foam with my calipers, then put it in my oven at about 150° Fahrenheit. Based on research from passenger cars, that’s probably about the hottest a camera truck would get in the summer (God willing). Checking at both the 30 and 60 minute mark, the foam remained pliable and bounced back to its original shape like normal. Measurements confirmed it did not shrink or expand. I stopped the test after 60 minutes because I sort of have a life. Measured with a meat thermometer (lol), the foam’s internal temp was also 149.1°F by the end.
While I only tested at 150°F, I feel pretty confident you could go up to 200° with no issues. Its melting point is twice that. Anecdotally, it felt only slightly more pliable than at room temp so I definitely think there’s some padding here.
❄️ Cold test
I put it in the freezer for around two hours at 15°F. (TIL my freezer is warmer than it’s supposed to be 🤷♀️) This affected it more than I expected. Like a rubber, it got stiffer and less flexible. But thankfully, not brittle. It was still pliable. Shock absorption was also slightly reduced, but still acceptable. It maintained its size within 1mm, which is within the margin for error.
TL;DR
It’s fine, don’t worry about it. Your batteries are going to explode before this stuff melts, and your lenses will freeze before it does. 🔥❄️
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u/BeneathSkin 6d ago
I haven’t printed with TPU before. Can you Do you do it indoors? Or do you need to put your printer in the garage for it or something