Why does nobody talk about how fast hot glue degrades in sunlight

I used some hot glue to fix a plastic planter on my balcony last summer. It held fine for like 3 months then just crumbled into dust. I looked it up on some DIY forum and apparently most hot glue breaks down real quick under UV light. Like within weeks or months not years. My dad always said hot glue fixes everything but I guess not outside. Has anyone else had outdoor hot glue projects just fall apart on them?

3 comments

3 Comments

tyler_wilson5d ago

... and that's exactly what happened to my friend Bob when he tried to fix his mailbox flag with hot glue. He thought it would save him a trip to the hardware store. Lasted maybe two months before it turned all brittle and started flaking off like old paint. He came home one day and the flag was just sitting on the ground with a pile of yellow dust underneath it. I told him he should've just used epoxy but he said he didn't have any on hand.

reesemoore5d ago

Haven't seen anyone mention that it's not just the UV light breaking it down though? Hot glue is thermoplastic which means it actually melts and resets in heat too. So if you live somewhere that gets hot summers the glue softens up, dust gets stuck in it, then when it cools it's all contaminated and cracks easier. That's why it crumbles instead of just getting weak. Sunlight hits it from both angles.

bennett.noah5d ago

Actually I had this exact problem last summer in Phoenix. The mailbox flag thing is real, I watched mine slowly sag in July then crack apart by September. The dust contamination part makes so much sense now because mine looked gray and gross before it failed. Bob is lucky his only lasted two months, mine barely made it through one monsoon season. Hot glue is just not built for real world outdoor use no matter what the package says.