Who knew : cutting foam polystyrene with a router.

[Sideways]

We had a new upvc back door fitted today.
The supplier left the door panel out for me to cut the hole for the cat flap.
I'd decided beforehand to make up a template and rout the hole to be neat and avoid any major muck ups but I didn't know exactly what the structure of the panel was going to be.
I was a bit surprised to find it was mostly foam polystyrene but it turns out a multitool cuts it easily enough and a router makes a real clean job of it.
Who would have guessed !

That should be warmer than a panel made of 1/4" ply

 

[Ollie78]

I knew what these were made of, only because accidentally smashed one whilst trying to pop the bead on, they are incredibly fragile if you hit them wrong or damage them when they are not in the door. Seem pretty strong once in position though.

 

[HOJ]

Had to do the opposite the other day, to what was, as I thought a solid timber door, took me an age to get the old cat flap panel out, but was intrigued to see how it was made up.