DIY Soap Mold Dividers?

I received some new molds as a birthday gift and I've been wanting to get some dividers for them. Since nobody sells dividers the size that I need I'll have to have them custom made which I imagine will be pricey. So what does any crafter on a budget do? Try to make them myself!

I've been looking for a good material to use and couldn't find anything to my liking. While browsing at Lowe's the other day my husband came across this No Parking sign. I would never have thought to use this! Perfect thin plastic material. Easy to cut, yet sturdy enough to hold it's shape. The best part...only $5! So I bought it and decided to give it a try.

First i measured my mold and drew lines where I would need to cut. I cut the strips with a good, sharp pair of scissors.

After cutting the strips I marked where the strips would interlock. Here I had to cut halfway and make the slits wide enough so the other strip would fit smoothly.

Then I put them all together to see if they fit. As you can see, some spots needed some more trimming.

After I finally got them pieced together properly I made sure they fit in my mold, remembering to allow some space for my mold liner. Looking good!

Now for the real test. Do they actually work? I whipped up a batch of soap to test them out. They fit in smoothly and everything looked good. I decided to do a basic CP batch instead of CPOP. That way if something went wrong I would know if it was the dividers themselves or if the oven affected them.

Here's where I find out if they really worked. Unmolding day! Most bars came out smoothly. 2 of them stuck in one little spot but aside from that I had nice clean lines. What I feared would happen though, did happen. Some of the lettering from the sign transferred onto the soap:( If it wasn't for this it would have been a success.

Does anyone know where to get this type of plastic material that wouldn't have any writing on it?