After seeing this post, Miss B passed along some questions, which I present with answers, at the end of my report:
Dear Miss B,
I didn’t take measurements on the project used in my original post, so I did another project to better answer some of your questions. For this project, I decided to do Spider Man’s face, since our mutual friend, Mr. C, is a big fan of Spider Man.
First, I pre-heated the oven to 375 degrees (Note this is hotter than originally listed, as I wanted to try to take video with the oven door open, and I thought the hotter oven temperature could compensate for having the door open.)
I started with a piece of #6 plastic, that was 2 x 2 3/4 inches and was significantly thinner than a penny.
I then did a Google search for images of Spider Man’s face in a size that would fit my piece of plastic, placed the plastic directly on my computer screen, and traced the image using red and black Sharpies.
After Spider man was drawn, I punched a hole in the top left of my plastic (I thought this could maybe be something he’d hang on his backpack.), although it is very difficult to see in this picture.
After the requisite photo ops of the pre-baked Spider Man, he went into the oven on a sheet of aluminum foil.
I had the oven door open a lot, trying to take video and photos, and it took about 10 minutes until he was done. I also had to close the door a couple of times to speed up the process.
As much as I preach about trusting that the process will work out, I was really having concerns that having the oven door open or cranking up the heat had messed something up, but after about 11 minutes, I had my finished Spider Man.
And here’s the thickness comparison photo after baking and shrinking in the oven:
Drum roll, please:
So to answer Miss B’s questions:
The original tutorial (linked above) noted that there was about 2/3 shrinkage. Spider Man’s original dimensions were 2″ x 2 3/4″, and the finished dimensions were 5/8″ x 13/16″. If I did my math correctly, that is closer to 85-86% shrinkage, but it’s always possible that I did the math wrong. Are you doing fractions yet? Maybe you can tell me.
The hexagon was in the center of the lid of the cover of the pizza take-out container. It was a very, very small portion of the lid.
You can always take the figure out sooner; it’s just a matter of the impact that it has on your design. The amount of shrinkage that occurs before it starts to curl up is pretty minimal, so if you took it out before it curled up, it might not really look different than if you hadn’t baked it at all. The shrinking happens quickly and dramatically. It seems like nothing is happening, then – poof! – it’s shrunk and curled up.
If you took it out after it curled, but before it flattened, you would probably be stuck with a curled design (if it was your goal to have a curled finished product, no problem). I don’t know how malleable the figure is when it first comes out of the oven, but it is very hot. It would be challenging, hot, and possibly distort your finished project to try to flatten the plastic yourself if you pulled it from the oven early. So far, I have tried to control the size of the finished product by starting with a bigger piece of plastic, rather than trying to control the shrinkage.
(In case you couldn’t tell, Miss B has a beautiful, inquiring mind!)
One final note of interest: I learned something that surprised me with this project. The Sharpies dry quickly and permanently on this plastic. I know Sharpies are “permanent” markers, but I’ve used them on plastic before, when I’ve wanted it to be permanent, and it’s rubbed off. Not here!
I’d intended to leave Spider Man’s eyes uncolored, they way they are usually presented. Unfortunately, I forgot and started to color in his whole head. I quickly realized what I’d done, and took the plastic to the sink to scrub with soap and water. It didn’t budge! I’d been wondering how well the color would hold up on these, and it seems like the answer is pretty darn good.*
*Update to this Note: After a couple of weeks, I got around to putting a jump ring on Spider Man, and to my surprise, a very little bit of the color wore off onto my hands. My hands were a little bit wet, and the colored side of the image was rubbing against my damp hand. The color did wash off easily with soap and water; however, consider yourself warned that it is possible for the color to rub off of these!
Thank you very much for your questions, Miss B!