I was able to find some IDye Poly at a local JoAnn's Fabrics and Crafts so I picked some up and decided to try it out.
I started with the parts of a clear Mega Bloks Halo Spartan.
I washed the parts off in hot water to get the factory stuff off of them and set them aside to get the dye ready. In a 3 quart pot filled over 3/4th the way to full with filtered water, I added one pack of dye (Black for this test) and the color enhancer and mixed it well as it heated up to a little over 200 degrees F. Then I took the pot off the direct heat and let it cool to about 140 degrees F. I let it cool down some because I wasn't sure what the melting/warping point was for the mix of hard and soft plastic parts. With a strainer I dipped the parts into the dye for about 10 seconds. I wasn't sure how fast the dye would take so I was going to do a series of quick dips until the parts got to the tint I wanted. When I pulled the parts out after 10 seconds they were already much darker than I thought they would be (and darker than I was wanting) but had not turned to solid black yet.
I gave the parts a long rinse in cold water to help close up the pores of the plastic and set the dye stain. It's hard to tell from the picture (the lighting in my kitchen isn't great for phone photography) but the parts ended up a dark translucent black. I would recommend waiting 12 hours after doing the dye before doing anything with the parts to let the dye finish setting. I was impatient and only waited a few hours. When I was putting together a couple of minifigs that the parts were used for making I got some black smudges on my figures but no noticeable rub off from the parts. I did all this Friday night. I checked the parts again Saturday afternoon and no smudges when rubbing the parts.
I would say my first test went really well even though the parts got darker than I was wanting (but not darker than could still be useful for the end project). I'm not sure if the darkness of the tint was because of the amount of time in the dye or the amount of dye in the water...further experiments will need to be done to determine that. As the clear Spartan was available in a regular set (unlike their other translucent Spartans that are blind bag ultra rare finds) I have some more to experiment with. Besides the black, the other colors of IDye Poly that JoAnn's had were yellow, green, blue, red, violet and brown. I'm going to go back and get some other colors to try and will let you know how those turn out.
