the goop

Some years back I started dabbling with polystyrene (Styrofoam) and acetone (acetone). I was trying to make some plastic components for a computer I was building. What happens is that the polystyrene dissolves quickly in the acetone. Really quickly. A single polystyrene peanut is gone in just over a second and leaves only something like cobwebs. There's not much to polystyrene. It's mostly air. So it takes a lot of it to saturate the acetone.

I've been trying to get my house back in some kind of order. I have a lot of polystyrene to get rid of. And I have the better part of a can of acetone. So I shoved what polystyrene I could into a cup or so of acetone. Then, curious as to what would happen, I poured the ooze on a cookie sheet and put it on my roaster of a front step.

What my initial experiments showed was that as the acetone evaporates the goop develops a skin. This prevents further acetone from escaping as it evaporates. Since it can't escape it forms bubbles under the skin. My original experiments involved moulds made in plaster of paris. And they were small. Like the size of a Star Trek communicator pin. So acetone was able to escape into the plaster as well as into the air. This, and the small size, got it to dry quickly (3 days) and left only lots of tiny bubbles inside. When put on a cookie sheet, or something that won't absorb the acetone, it only has the top through which to escape so you get bigger bubbles. In the high heat I expected something like a translucent soccer ball to form.

Here's what really happened.

This is just seconds after pouring the acetone.

Less than a minute after the first picture. You can see the edges starting to bubble.

14 minutes later. BIG bubbles!

Another hour later

another 45 minutes. There's a big bubble in the middle. Kinda like an egg.

35 minutes later the big bubble had burst and collapsed. It didn't form a big bubble again in the next two days of baking in the sun. It was firm, but flexible (still not dry) when I finally brought it in after 3 days.