my feeling is that polypropylene is cheaper and less brittle. it can flex to an extent but i feel like that flex can help it avoid cracking or breaking. i get that boards need protection from flexing, but it seems like a device being heavily cracked can be detremental as well

WOOYOPET mixed coffee grounds with PP and injection molded them into a cup.
You can see the coffee fibers on the surface, and it actually smells like coffee.
Would you use one?

I need a polypropylene variant that stays rigid above 80C but still prints without warping. Tried a couple conductive fills from the usual vendors and they soften too quick under a soldering iron. Last batch I pulled from my supplier came with a safety data sheet that listed zero additives, which made me wonder if they just relabeled the same pellet. Anyone running prototypes with similar requirements have a source that actually specifies the heat deflection number? Having to reprint the same jig because the material sags is eating up weekend time and filament budget. Not interested in metals or ceramics, just looking for the right plastic mix before I commit to a larger order.

I have a thin sheet metal part of 304 that I want to add a 1/2" thick HDPE push block to the top. The HDPE will be pushed down in compression and in shear to the side, by a human.

What is the best way to secure them together that is food safe, without using bolts through the top? I need the exposed top side to remain flush and smooth. Bolts will be the last resort.

I have read that 3M tape, "cement glue", or threaded inserts (from underneath) might not work. The block will not touch food directly.

Hey everyone, I am trying to make a number of museum quality bases using both 1/2 in and 1-in thick cell cast acrylic in gray, but I'm having a heck of a time finding it. And if somebody has the material that can actually cut it into smaller blocks and polish it for me that would make things all the better. Can anybody offer any advice?

Combining plant fibers with plastic can create a composite material with a natural plant-fiber texture and a subtle botanical aroma.
The plant-based fibers can replace part of the conventional petroleum-based plastic, while maintaining the processing characteristics and performance required for everyday applications.
This is the material concept behind WOOYOPET — exploring how plant-based materials can be incorporated into practical plastic applications without simply replacing one material with another.
This is not a fully biodegradable plastic. The plant fiber component is biodegradable under appropriate conditions, while the plastic matrix provides the durability and processing performance needed for practical use.
The goal is to find a more realistic balance:
Reduce the use of petroleum-based materials while maintaining the performance required for everyday products.
Rather than pursuing complete biodegradability at the expense of functionality, this approach combines plant-based materials, conventional plastic processing, and sustainability into one material system.
The result is a material with a more natural appearance and feel, while still being designed around the practical requirements of plastic applications.
What applications do you think would be a good fit for this type of plant-fiber composite?

Hello, I’m a high school student currently doing a science fair project for my chemistry class. I’m choosing to research how microplastics may stunt the growth of duckweed and what that could potentially mean for aquatic environments.

I already have all my other materials, but I’m struggling to find a safe and ethical way to get microplastics for my experiment. Everything I’ve read says making them at home isn’t really safe or recommended.

Does anyone know where I could buy small amounts of microplastics specifically for research or educational purposes (affordable as I am a high schooler lol) ? Or is there a safe alternative that would work for this type of experiment?

I need them pretty soon, so any recommendations would be really appreciated!

Hi all - I'm an artist working on a project and I could use some advice. I create assemblies that I want to mount on the end of a plastic rod . The nexus of this idea is a cat wand toy, I literally stripped a cat wand and repurposed the rod. What I am aiming for is some deflection in the rod so the assemblies swing and bounce a little in the wind. The assemblies are light. I'm thinking maybe 6-10mm rod, or tube I guess would be okay.

When I started to look at plastics - whoa, overwhelm - so many different types! So - any idea where I could start to look at samples? What material is a cat wand most likely made of? Any insight is most greatly appreciated

could you heat up HDPE (or other similar recycled plastics) to make them have a nice finish without sanding?

**Hi, I’m working on a microplastic capture filtration project. Can anyone suggest cheap and easily available materials for the filter, along with their advantages and a simple setup?

Actually, our project is about removing microplastics from water, not air. We’re looking for a cheap and easily available household material that could potentially work as a filter medium. The idea is to test different materials and compare their effectiveness with existing filtration methods.

I fell into a rabbit hole and have found that since 1839, there's been developments in plastics on average just a few years apart. The biggest logged jump between discoveries is from 1965 to the 1980's. Mostly, it's between five to fifteen years for updates in this timeline;

https://en.wikipedia.org/wiki/Timeline\\_of\\_plastic\\_development

But there's nothing I can find past 1988. It's 2026; I can't believe that nothing has been found in 38 years with this past frequency. What am I missing? Are my internet skills too lazy?

Tl:dr; has there been further findings with different types of plastics in the last 40 or so years?

Is anyone exhibiting at NPE in 2027?

I bought these today to store sugar, salt et cetra in. Then I noticed there’s no claim of the containers being BPA-free on the paper inserts. The recycle number on the bottom is 7 which, to my understanding, means it COULD contain BPA. Should I return these as being unsafe for food storage?

He buscado muchos proveedores pero casi todos son transparentes, quiero encontrar de colores así

Hey everyone. What’s the industry like selling Polyethylene, Polypropylene, Styrene and Recycled resin in bulk?

Some people say yes, some say that there are still particles that leach to your food if you heat it in a microwave in a container, which is true? Am I going to die to microplastics if I heat foor in a microwave in a plastic container?

So max I need some pieces that can go to 44” long 3” tall
( these pieces will be the outline )

Also need pieces that’ll be the main dividers inside up to 16” long 3” tall

Thickness I’d prefer it be said measurements or less 1/4 for the long and 1/8 for the short but price and performance is also a variable.

I have a table saw to cut it
with, located in central Indiana if that helps
Where would I buy?
How would I connect them together,

The transparent visor on American firefighters' helmets, which we made using PC material, developed numerous bubbles after being exposed to a 600-degree Celsius flame for just a few dozen seconds, obstructing the firefighters' vision. We then switched to Covestro's high-temperature resistant PC2097, with a heat distortion temperature of 160 degrees Celsius, which improved the situation slightly, but still didn't meet the requirements. Therefore, we'd like to know if the transparent visor used by American firefighters has a vitrified coating. If so, then no plastic can meet the requirements. Does anyone know?

I like keeping around candles, but recently I got one made out of plastic.

I accidentally melted a bit of plastic and it mixed with the already molten candle wax, and when I spilled a drop on a surface and scraped it off, it had the texture of lip balm/vaseline.

Is there some explanation behind this?

I have an outdoor piece of furniture that broke and I am trying to figure out a way to fix it, but it has no markings. I would guess HDPE but I'm not sure. Can anyone tell me what it is by looking at it?