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UV stability is only one aspect. What happens when you build a greenhouse out of these and the temps reach high enough to deform these? How long do you think th
by malfist 4y ago
UV stability is only one aspect. What happens when you build a greenhouse out of these and the temps reach high enough to deform these? How long do you think the structure will stay stable with or without UV paint?
I've had a greenhouse melt nursery pots left in it and they're made out of polypropylene, which has a glass temp 50C higher than ABS.
- traverseda 4y agoThe inside of your greenhouse is reaching ~150 degrees celsius? Why aren't your plants boiling? Is it just a color thing? EDIT: the glass transition point of PP is -25C, vs ABS's 105c. I think you confused glass transition point with melting point, they're very different things. I think polypropylene will always be a bit soft, and will hold a shape that it's deformed into, it it hold that shape long enough.
- ehnto 4y agoSorry I think you might just be mistaken. If your greenhouse is reaching 150c then there's actually not that many common plastics that wouldn't hit the glass transition temp. There are some exotic "plastic blends" like glass or carbon fibre/mineral blends that can do it, but even most of those are less than 140c. In this table even the modified versions of polypropylene have glass transition temperatures below negative: https://omnexus.specialchem.com/polymer-properties/properties/glass-transition-temperature#A-C https://omnexus.specialchem.com/polymer-properties/propertie... I don't think it should be too surprising that 3D printing filaments can withstand similar characteristics to other outdoor plastics. One commonly used outdoor plastic is PVC which has a glass transition temp between PETG and ABS: PETG: 80c, PVC: 85c, ABS: 103c. If you left a PVC pipe in your greenhouse you wouldn't expect it to deform.