Queadlunn- I’ve tried a couple new methods for my polycarbonate gem faceting. I cut another gem (the shape turned out a lot better this time too!) and this time I used iDye Poly to color it.
-WALL OF TEXT INCOMING-
The method of how I made the gem out of poly is pretty much the same as the last one (LINK), I had a cylindrical piece about 1x3” in size and I ground it into a (base) 3-sided pattern that worked pretty nicely. The disk sander we have currently has 80-grit on it, from there I moved to 220-grit, then 400-grit, then a felt polishing wheel (just sitting on my desk), then burnishing with cloth. This got me to image #4 which was looking really nice.
Since my last attempt to dye poly with standard fabric dye was a failure, I used some synthetic-compatible dye that Cata had bought me (iDye Poly, see image #5). I got the dye ready on the stove and dipped the gem in it for about 3 minutes total in 2 runs. I was really careful with the temperature this time (might have been around 85c or 90c or so) since the first test gem ended up with tiny thermal fractures on many facets. After the dye bath I was at image #1.
One drawback with the dyebath is that while it does seem to penetrate, it’s less than 0.2mm (with solid plastic this is understandable) and the dye process does take a bit of the luster from the earlier polishing off and it’s not something you can get back with polishing since you’ll just wear through the dyed plastic.
Since the gem wasn’t quite as shiny as I wanted now, I added a thin coat of Future to bring it back to a nice shine (image #1). Worked pretty well but I’ll need to airbrush the future on next time.
Overall, I think this is a great process, given that you have access to a bench disk sander and access to larger pieces of polycarbonate.
I’ve got one more of these planned, a larger one. I’m thinking of taking video of the faceting process but I’m still figuring that, and the material, out. Also thinking of trying a long-term soak dye (cold) to see if that gets the color farther in the plastic so I can re-polish without having to topcoat the gems.
Scientist have developed a new way of making plastic by replacing crude oil with sugar and CO2. The researchers from the Centre for Sustainable Chemical Technologies at the University of Bath, UK, created a new type of polycarbonate using sugars and carbon dioxide in a new process that requires low pressures at room temperature, thus making it cheaper and safer to produce than current methods.
The polycarbonate is biodegradable using enzymes from soil bacteria. The resulting plastic is strong, transparent and scratch-resistant and could potentially replace current polycarbonates in items such as baby bottles and food containers, and as the plastic is bio-compatible, the researchers believe it could also be used for medical implants or as scaffolds for growing tissues or organs for transplant.
Dr Buchard, Whorrod Research Fellow in the University’s Department of Chemistry, said, ‘Chemists have 100 years’ experience with using petrochemicals as a raw material so we need to start again using renewable feedstocks like sugars as a base for synthetic but sustainable materials. It’s early days, but the future looks promising.’
Queadlunn- I’ve been messing with polycarbonate plastic the last few days. One thing is something I’m still working on. The other started out as a cut-off of a 1.5″ PC rod (about1.5″r2x1.5″). I used our bench sander’s 5″ disk (with 80 grit) to do a freehand kind of faceting that turned out pretty nicely.
I started out on the sander with 80-grit, then moved to 200-grit sandpaper taped to a piece of sheet-metal laminate. I then used 600-grit with a machine oil on the paper to lubricate (worked okay). This got me to the image labelled #3.
Since I know that some plastics can be dyed with fabric dye, I decided to try it out. Due to the plastic I was using, or the dye I had on hand, the gem didn’t really change after ~50 min. Because the heat of the dye bath the polished surface of the larger facets ended up crazing (maybe a thermal effect?).
The gem was still mostly the standard polycarbonate blue at this point, so I mixed a purple future wash (~120ml Future, 2 drops each red & blue food coloring) and did one coat. This added a bit of color to it as well as add even more gloss to the gem.
Not bad for a day of tinkering, I think I could do another gem like this (given I had all the materials on-hand) in about 3 hours. If I end up making more of these I’ll try to make some kind of faceting jig for our sander. Could be fun!
I used Dylon because it was what we had on hand. A dye for synthetic materials ( like RIT Dyemore or iDye Poly) would probably work better. A test for the future.
So, after figuring out that polycarbonate possibly isn’t getting dyed I did a test. I soaked a bit of polycarbonate rod in blue iDye Poly for a few days. When I took the piece out, it looked like it had been dyed a really dark blue, which seemed great. After I had dried it off, I realized that the surface of the poly was a bit soft or gummy. I was able to cut into the surface with my fingernail. I took the piece back to my desk and found that the dye had built up a ~0.75mm layer on top of the poly, no penetration at all. It seems that polycarbonate does not really take dye made for artificial fabrics, though it does create a nice tinted coating.
I did a quick new crystal using a bit of acrylic rod instead of polycarbonate. This works well, just acts very differently from poly (much lower melting temp, softer material) and I’ll likely stick to poly for crystals that need really finely done facets.
I soaked the acrylic crystal in some iDye Poly as well and it at least creates the same surface coat that occurs on the poly, I’ll do a test with this as well to test the dye’s penetration.
Some other notes, pretty much all of the polycarbonate crystals have some amount of surface crazing, from a huge amount on the squat gems to just a few, tiny occurrences on the larger ones. I think this may be due to the heat generated during sanding and/or the plastic reacting to the dye in some way.
Also, we tested the iDye Poly on some transparency material. Didn’t work either due to the coating to allow inkjet printing or due to lack of penetration.