So I decided to get started with the testing even though I only have 3 products.
Shapelock - Friendly Plastic (in pellet form) - instaMorph. I went for the smallest amounts I could get. Shapelock mails out 1.4 oz for just $4.59 shipping. Friendly Plastic's smallest amount is 1.4 oz - $6.59 (free shipping with Amazon Prime or $11.99 shipping from the maker Amaco (ouch)). Instamorph $9.99 for 6 oz (free shipping with Amazon Prime).
I did a quick weigh in to see if any of the companies shorted me on product and none of them did.
Products all appeared about the same. The Shapelock pellets were the larges. The Friendly Plastic had the most stringy tails. InstaMorph were the most uniform.
For testing purposes I decided to use a silicone Maoi ice cube tray. I wanted to see how the material took the shapes of the mold.
I filled up 3 sections of the mold to the rim to measure the same volume of each product. I wanted to be able to address the shrinkage question so I kept each amount even.
So on to the melting. Because only some of the products discuss melting in the oven, and because microwaves can vary, I followed the directions to the letter for hot water melting. For Shapelock the water was 150 deg F, for Friendly Plastic the water was 120 deg F, and for InstaMorph the water was 160 deg F. When the material is melted it turns clear and is ready to kneed together. At their specified temperatures only the InstaMorph started to melt.
So with the water at 160 deg F I reheated the Shapelock and Friendly Plastic and they began melting.
When the material is only partly melted it is partly clear. This is the Friendly Plastic partially melted - it kneeded together but still needed to melt some more.
It took about 3 water changes to melt the material fully. After kneeding the above partially melted Friendly Plastic together so that it was not loose pellets I just dropped it into the water on the stove - that led to much quicker melting.
I took each fully melted sample and kneeded it and then pressed it into the Maoi mold by hand. After placing all 3 in the molds I ran them under cold water to cool them quickly. I squeezed the Friendly Plastic Maoi out too quickly and squished its face - so it went back in the pan of water on the stove to reheat - and then back in the mold. Here it is in the center - still hot - while the other two have cooled and thus are white again.
Note the volume in the mold. I believe that the reduction is just the elimination of the spaces between the pellets.
After they were fully cooled all 3 Maoi came out of their molds.
Each product took the mold shape and details very well. The lines were crisp and defined.
I could not bend or break any of the 3 by hand.
It took placing a Maoi in the vice to do anything. This one bent - but did not tear or break - at the thinnest point of the mold. When I took it out it went back to the original position - with a crease in it.
I decided to try a couple more pieces with the Instamorph. After melting 1 oz of material I kneeded it into a ball. The more the material is worked and folded the more effort it takes to get the fold lines and/or air bubbles out of the material. If you are patient and careful you can get these out. It helps to put the piece back in the pan of hot water periodically to keep it melted.
I then cut out a star with a cookie cutter. The cookie cutter pressed through the plastic with some effort and pushed down the top edges but it did cut out the shape. The pieces outside the cutter went back into the pot to remelt and reuse.
Because the cutter pressed down on the edges and created a bulge in the center, I hand pressed the center of the top side back down and up against the walls of the cutter. When cooled this showed up as an uneven top.
I used a belt sander to smooth this down. The temperature apparently got just to the melting point as the edges showed some melt.
Cutting the material with the cookie cutter was possible - but it distorted the top of the shape significantly. If I was going to use a one again for the shape - I would simply press the material down into it.
I also tried making a 4" cylinder from the InstaMorph. I worked the material and rolled it on the counter. Back into the water in the pan on the stove to remelt it and keep it workable. Rolling it on the counter got a good clean cylinder.
I drilled out the ends with my standard drill to accept two carbon spars. The tailings can go right back into the pot to be remelted.
I could not bend it or get any significant deflection by hand.
Putting in two 32.5" carbon spars and bending them to a full half circle the cylinder deflected some but not much. I have this in the window frame now and will report back on its status after 24 hours.
Based on the workability of this material and these intial tests, I am very impressed with this material and I think it may be fantastic for fittings. Shaping it appropriately is easy because the material can continuously be remelted and reworked. And if you aren't satisfied - melt it and start over. It seems to be slightly flexible - definitely not brittle - but plenty strong for fittings.(fixed a couple of the tags Ben-thief)