Why are my plexiglas inserts cracking?

[orangeblossom]

I have a wooden mold, and I use plexiglas inserts to create separate bars (i used it yesterday to make salt bars). When I uncovered it today, the plexliglas was all crackly at the top (NOT where the soap was touching, but at the top where there was no soap.

This happened to me with another mold a week or two ago, and I did CPOP with it, and it happened then, but I assumed it was the heat of the oven that did it. But this time, no. I have used these for years and nothing ever happened.

Are they just "getting old"? Was it heat? Essential oils? Has this happened to anyone else?

One was 1/8 inch thick, one was 1/4 inch thick.

I want to have at least one mold that separates into bars to make salt bars, but I want it to last (the plexiglas also keeps breaking where the cuts are to make it fit together).

Does anyone have a mold like this that is not breaking that they could recommend?

(Lots of questions!!!)

 

[Tabitha]

What brand are your molds/inserts?

 

[orangeblossom]

I have no idea.
I bought the one that is 1/4 inch thick on ebay, about 6 years ago, and then I moved and lost any and all info about where I got it.

The other I "made" myself, by just cutting 1/8 inch stuff, that is the right dimension, and I insert it along the log mold where I want it separated after I pour.

 

[Sunny]

(just my newbie input, having never used this material before) I'd guess if they last for 6 years, that's pretty dang good! Maybe they are just getting old!

 

[orangeblossom]

Yeah, maybe. I just thought it was strange that it NEVER happened before and then all of a sudden they are all cracking!

 

[pixybratt]

my ex hubby used to be a glass man so I know a little about this just in general.

Plexi-glass can get brittle with age and will get crackles from heat, come time cold to hot can make it worse.

if you have a Tap plastic or something similar in your area they may be able to make new bits for you, and maybe give a better idea how to make it last longer.