Garden Railway Forum

Just a word of warning, this is what happened after a few sunny and hot (well not so hot in Finland) days to my 3D printed oil drum. Bottom of the drum has bulged out and the top plate has deformed. I think it was printed with Standard Filament (temperature resistance up to 65°C).

Yikes, whatever's in that drum must need a hazmat label!

I've had some things printed in PLA warp over time/heat/direct sun. PETG has given slightly better results, though it can warp for other reasons (humidity, I think). I've heard ABS is the best common FDM material for heat resistance, but I've yet to try it.

@GAP did some testing a couple of years ago for outdoor use: https://gardenrails.org/viewtopic.php?p=176253#p176253 I was surprised to hear that black PLA was slightly tougher than other colors of PLA but since then that has been my experience as well. I don't know if any FDM printed item will be able to handle direct sun in an enclosed porch/balcony though.

My first questions are, is it hollow and sealed and how dense is the internal honeycombe? Because once the plastic softens the internal air will heat up more/faster and the increased pressure will do strange things to the soft plastic and that looks exactly like what has happened on the top - the pillow effect is the hot air pushing up between the honeycombe.
I've had PLA windows and doors outside 24/7/365 for a number of years with no significant damage apart from some roof ridge tile strips which have curled slightly.

the drum is hollow and sealed. internals i do not know as it is a commercial product. yea the hot internal air expanding sounds logical

I first came across that pillow effect soon after I started 3d printing. It showed itself on the tops of buffer beams that I was printing integral with the rest of the chassis. At the time I was using filament from a company that no longer exists but they had a really good customer service dept who told me exactly what the problem was. The answers are (a) print a thicker top ( more layers) and (b) make the internals denser (c) if the model/design allows it, leave breathing holes in the sides.
Not much you can do about a bought in item, but worth remembering for your own printing.

About two years ago I reported on my purchase of the 16mm scale 3D printed L&B mobile crane, which is a superb model and I am delighted with it.
During its first outing to a garden railway open day on the Gower (Wales), and on a particularly warm day, it sat in its box waiting a running opportunity. The temperature rose and the jib distorted to such a degree it caused the crane to derail...
After contacting the manufacturers and describing the circumstances the jib and winding gear were immediately replaced without question, but I never did find out what material it was made from.
Certainly there is a risk involved wherever 3D printed items are exposed to high temperatures.