View Full Version : Plastics

2011-06-30, 07:15 AM
Ok...I need a bit of help here. I enjoy experimenting with plastic molding, but until now, I've been screwing with shapelock (http://shapelock.com/). It's fun, it's useful, but it's also like $20 a pound.

So, while fantastic for prototyping and molding, it's less useful for actually making things you want to stay in one shape. I need to find a good source of plastic stock for a reasonable price. I'm ok with rods(provided they are no wider than say, a glue stick), or beads, but sheets don't really feed well into anything. My equipment can handle up to about 350 degrees Fahrenheit, but anything above that is dodgy. Any ideas?

2011-06-30, 07:47 AM
Have you looked into resin casting? Make a silicone mold of your original and then pour in the resin for casts.

2011-06-30, 08:45 AM
Have you looked into resin casting? Make a silicone mold of your original and then pour in the resin for casts.

I have...casting isn't a problem for me, I've got all the goodies for that...but resin has some annoying properties. Some resins react extremely poorly to paint(specifically, aresols, like spray primer), some have really long set times...some of them melt at temperatures that are just too low.

Plus, getting mold release off resin is fiddly compared to plastic. Gotta use soap, water and a toothbrush to get it out of the pores. Some kind of plastic would be ideal...I just need a moderate-low melting point plastic in some kind of feedable shape in a reasonable quantity.

2011-06-30, 02:00 PM
If you have any experience with CAD or 3D modeling software, you may want to give 3D printing a try. In case you don't know, 3D printing is a process by which a computer numerically controlled, or CNC, machine, uses an additive process to build up a physical 3D model layer by layer. The most common method uses an extrusion head to deposit a thin molten plastic filament. The printers themselves are extremely expensive, but you can buy time on one from a number of Internet businesses like Ponoko (http://ponoko.com/). You design the device, product, sculpture, or figurine, send them the files and some money, and you get a physical copy in a week or two.

2011-06-30, 03:09 PM
I'm familiar with the process, but the extrusion isn't really the problematic bit...I'm in need of feed stock.

Do you know of any 3d printing place that might sell plastic feedstock in reasonable quantities(5-20 lbs) that melts at a reasonably low temperature?

2011-06-30, 03:20 PM
Well, there is MakerBot Industries, makers and sellers of the open-source, kit MakerBot 3D printer. They do have an assortment of ABS plastic filament used as feedstock for their extruder design, but it looks kind of expensive.


2011-06-30, 03:29 PM
Yeah...$25+ a pound is higher than I'd like to pay. I have quite high tolerances for what I can feed, and I feel like I've got to be missing something obvious. After all, if plastic was always this expensive, a *lot* of items would be far pricier.