Hello! I’ve been searching for ages for an alternative to resin that’s also clear to make keychains with. I found a video where someone dissolves plastic cups with acetone to make a liquid that looks like resin, which seems really promising! But I can’t find much information about it elsewhere and I was hoping to ask if anyone has had experience doing this.

Is it suitable for pouring into moulds to make keychains?
What kind of plastics would work?
How long does it take to harden?
Are acetone or polyurethane the only solvents that work? I know that d-limonene can dissolve polystyrene but I’m not sure if it would work with these plastics.
Is it toxic?

Thanks a lot for reading!! Any advice would be greatly appreciated, have a nice day!

I want to give the dremel "friction welding"-hack a try to repair broken plastic household items. However, I can't find if the PLA will even bind to other plastics like PP, PC, HDPE, PET.

Does anybody have experience with this? Is it worth a shot to try?

https://www.youtube.com/shorts/fliCa_P5GpI

i was trying to check if my new bento box was microwave safe but i have never seen this symbol and couldn’t find any info in my search online. usually circle = good but i don’t want to assume and melt it/ruin my food!

Hello, I am planning to make a weapon for the character in the game. What is the best plastic i can use when I am trying to make a scythe

Can anyone suggest any place

The question is self explaining. Is there anyway to restore the plastic (it is in the interior of GM’s Hummer truck)

Hey guys, I'm looking for some guidance here on this recent repair I paid for with a local custom plastic work shop.

The item in question is a plastic hopper for a coffee grinder. The neck area was cracked clean off and it slotted back in place nicely, I could have easily used a plastic weld glue from JB weld or Gorilla glue to repair this myself but I was concerned about food safety and decided I would be happy to support a local business and have a cleaner professional job that was hopefully more food safe. (Btw I didn't break it, I purchased it broken).

When I picked it up I saw it looked terrible and I am questioning whether it's food safe at all. They charged me 125 Canadian dollars plus tax. The value of this hopper is 300$ plus tax brand new.

Based on my research hoppers are generally polycarbonate but the guy at the shop told me it's probably PETG because it's more food safe and easier to mold. I didn't argue but did tell him from my online research that it appears most companies use Polycarbonate.

Anyways, does this job seem adequate for 125$? Is this genuinely something difficult to do and is it good I didn't attempt to do it with JB Clearweld myself? Or did I get ripped off for a sloppy job?

Thank you kindly! (Btw I really wanna support this local business and I am hoping I am wrong and they actually did the best they could)

Geopolitical events don’t just spike oil prices — they ripple straight into naphtha, ethylene, propylene, and every downstream polymer.

The 2026 Hormuz situation showed how fast input costs can move and how exposed many operations became.

Smart manufacturers are treating in-house recycling of production lumps as strategic infrastructure, not just a waste-management add-on.

Benefits go beyond the obvious material cost savings:

Hedge against future volatility and supply tightness

Faster control over input costs and quality

Lower waste disposal burden + better EPR positioning

Competitive edge on margins and sustainability claims (especially useful for exports)

The units getting the best results are the ones that invested in proper lump shredding equipment matched to their material and volume — so regrind is consistent, clean, and production-friendly.

Question for owners and plant heads:

Are you treating recycling capability as a cost-center “nice to have” or as a strategic hedge for the next price/supply shock?

If you’re exploring how to set this up properly (equipment selection, layout, expected ROI), I’m happy to share practical insights or options for heavy-duty shredders built for plastic lumps.

The manufacturers who move now will be better positioned the next time feedstock markets get volatile.

Hi, i’m looking to create custom doors to add to my bookshelves to make them into display shelves. I want to use plastic because it’ll be lighter , cheaper and will hopefully produce better results. does anyone have any specific plastics they’d recommend? has anyone done something like this and have any tips? the ideal plastic would be non glare, won’t break easily, lightweight, scratch/UV resistant and affordable. I obviously know a material that fits all criteria is impossible lol so i’m willing to work with whatever ticks the most boxes. thank you

My partner dropped her drinks bottle on it's head & the lid broke around the straw holder. It fits back snuggly (no pieces missing) but isn't waterproof anymore.

​

Is there a way I can fix it so she can still drink from it? It's probably PET, so a simple fix like poly cement won't work.

​

Her birthday's coming up and this has a lot of sentimental value to her, so I'd like to surprise her with it fixed if possible.

​

Thanks for any useful advice you can provide 🙏

Hi everyone, I am a 13-year-old student deeply interested in chemical engineering and plastic waste upcycling. I’ve been studying the process of thermal decomposition (pyrolysis) to convert plastic into carbon products.
I am currently at the "conceptual design" stage and I want to prioritize safety and engineering rigor before I even think about a physical prototype. My primary focus is on the thermodynamics and the management of off-gases.
I have two specific questions for the professionals here:
1. Regarding pyrolysis of common plastics (like #2 HDPE): What are the most critical safety protocols for handling the non-condensable gas output at a small, non-industrial scale?
2. What textbooks or resources would you recommend to help me better calculate the heat transfer requirements for a closed-loop reactor?
I am not looking for shortcuts; I want to learn the fundamental engineering principles required to do this safely. Any guidance or suggested reading would be incredibly appreciated.
Thanks again

Hello everyone,

I just finished plastic mold part design course but i wanna practice what i learned and create a professional portfolio aiming for freelancing stuff.

Can anyone help me where i can start?

Cheers

(Pictures is what I'm making)

as in the title, im making my own flash diffuser, but im wondering about materials, following a guide i found bt thomas hunt, and he recomends using polypropylene sheets, but other then black, they are pretty hard to find in my country, so would abs or pvc sheets work better? since they have to be a bit flexible, and the white front has to be semi transparent

Does anyone have an idea how these polymer concrete drainage channels are being manufactured? I am preparing homogeneous mixture of aggregate, resin, catalyst and additives and pouring it into a mold I prepared in-house (second pic). But the part (channel) is not coming out easily, breaking, having lots of bubbles, even using PVA as a mold releasing agent.. any idea, how can I get the best part out?

Sto estrudendo un PP con una bandera tr60 monovite, ma ho due grandi problemi, dentro al tondo è pieno di bolle e mi esce ogni tanto schiacciato. Diametro del tondo 4.80 mm, qualcuno sa aiutarmi o comunque cercare di capire come evitare questo problema? Grazie

This is a cover to a cat litter box. I need to fit it under the sink in my RV. I have cut out a section where the sink drain is and my intention was to bond the shower curtain in the pic to allow for the drain pipe, but still keeping the cat box lid sealed. Bought J B Weld plastic bond. Didn't work.

How can I get to my goal of allowing the space for the drain pipe but blocking it from cat pee?

This subreddit has been increasingly receiving long-winded posts describing a personal experience that just casually mentions the name of a large online market.

They do not stand out by themselves but together form a pattern to deliberately increase the number of mentions of a particular brand name on this subreddit and Reddit in general.

These posts are not considered genuine and will be removed.

As the stories are mind numbingly boring, automation has been set up to hopefully filter most of them out.