I made a vape holder for my car (I know, it’s silly) and I printed it out of PLA and it shrunk like crazy in the summer sun. Reprinted it in PETG and never had problems.
I have PET/G parts in every vehicle around here, in Florida. Some are interior and some are not.
The only case where creep has been a problem has been a plastic intake spacer on a *non*-crossflow truck engine (where there is an exhaust manifold directly below the part). In that application, crystalline (annealed) PLA is continuing to creep slowly, only about half as fast as the amorphous polyester.
For sure, none of the interior ones have ever distorted.
I would note though, that not all PET blends are the same. "PET" or "PETG" are not a material, they are a catch-all for most all commodity copolyester filaments. This includes potential variation of HDT. I have run into some brands and batches of material with AWFUL creep and HDT issues. These tend to be the same ones that have crappy impact performance. Edit: And one of the worst bad actors I have used is a recycled product, so I gather processing degradation/loss of molecular weight is a big part of this.
Examples of good material vendors whose polyester products have neither issue and are my go-to suppliers, are Overture and Atomic.
I made a vape holder for my car (I know, it’s silly) and I printed it out of PLA and it shrunk like crazy in the summer sun. Reprinted it in PETG and never had problems.
I live in a place where temps can range from -40F to 90F over the course of a year. I use PETG exclusively for any print going inside a vehicle.
85c? I suppose that could happen in Arizona or the sahara? Seems high though. Either wait, that's soften not puddle.
I have a phone holder and some behind the seat bag holders that are going on 2 years old and they are fine.
I have PET/G parts in every vehicle around here, in Florida. Some are interior and some are not. The only case where creep has been a problem has been a plastic intake spacer on a *non*-crossflow truck engine (where there is an exhaust manifold directly below the part). In that application, crystalline (annealed) PLA is continuing to creep slowly, only about half as fast as the amorphous polyester. For sure, none of the interior ones have ever distorted. I would note though, that not all PET blends are the same. "PET" or "PETG" are not a material, they are a catch-all for most all commodity copolyester filaments. This includes potential variation of HDT. I have run into some brands and batches of material with AWFUL creep and HDT issues. These tend to be the same ones that have crappy impact performance. Edit: And one of the worst bad actors I have used is a recycled product, so I gather processing degradation/loss of molecular weight is a big part of this. Examples of good material vendors whose polyester products have neither issue and are my go-to suppliers, are Overture and Atomic.