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blunstone
(@blunstone)
Eminent Member
PET for outside use

Hi, I've printed the left -hand decorative moulding in Prusa PET. It has been primed with plastic primer then painted in satin gloss and screwed to the wall with 2 woodscrews. On the right is a hardwood piece (didn't have enough for both sides).

My question is, will this last. It's South-west facing (SE of England). The two possible problems are getting too hot - deforming and different expansion rates compared to the brickwork in very hot or very cold weather - cracking.

If you have any experience of this type of project or any thoughts, I'll be very grateful

Posted : 09/09/2021 1:56 pm
Diem
 Diem
(@diem)
Noble Member

It should be good for at least as long as the paint job on the woodwork.  PET is susceptible to UV light; the paint will protect it to a useful degree.  The UK will not get to deforming temperatures, thermal expansion cracking depends on how tightly it's screwed down but you will probably be OK.

Unprotected PETG is not UPVC, it does change when exposed but the first change is cosmetic and your paint will both protect and mask that.  Some polymer chains will break over time and this seriously impacts working parts, your unstressed decorative object is less susceptible.

Cheerio,

Posted : 09/09/2021 2:44 pm
blunstone
(@blunstone)
Eminent Member
Topic starter answered:
PET for outside use

Thanks Diem - I can travel in hope!

Posted : 09/09/2021 3:35 pm
JoanTabb
(@joantabb)
Moderator

these roses were printed in PETG at  the beginning of the year, and they discoloured. they have now been painted

Hopefully they will last a while!

Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 10/09/2021 11:36 am
Swiss_Cheese
(@swiss_cheese)
Noble Member

Paint should protect fine from the UV, however if heat should become an issue you could always just print the part out of ABS or ASA.

I really like the idea of the printed exterior House Trim, for certain items it makes sense.

 

Enjoy

 

Swiss_Cheese

The Filament Whisperer...
Posted : 10/09/2021 6:15 pm
ssill2 liked
blunstone
(@blunstone)
Eminent Member
Topic starter answered:
PET for outside use

Thanks Joan, funnily enough I was in Manchester earlier this week. I should have made a detour - would have been a good follow-up to visiting Lyme with the Legh's family history.

And thanks Swiss_Cheese, I've never used ASA or ABS - I was put off them when I started printing by references to fumes, but I know you're right if this doesn't last and I'll have to bite the bullet. 

Posted : 11/09/2021 8:30 am
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