john wrote:
"Steve Walker" wrote in message
...
Greetings -

Because our cat won't take no for an answer, we need to reinforce the
catflap against escape. The simplest solution is a slide in
'guillotine' panel which covers the whole assembly (insert jokes
about sharpened edge, baited with tuna etc).

I have various types of stout thin board, that's not a problem. But I
need some J-Channel to slide it in and out of. Something
like 10-20mm wide at the back, and 5-10mm wide at the front, and
able to accept a 3-4mm board sliding in. Two lengths of 250mm would
be adequate, sturdy plastic or aluminium would be ideal.

I've seen similar stuff on the back of self assembly furniture, to
hold the hardboard back on. Common-sense says there's probably
some way to scavenge or convert it - cut-down electrical trunking,
alloy channel for fixing greehouse glass or summink?

Ideas very welcome...!

For your catflap you need to
glue some very small trunking around the edge inside. Then slide a
piece of plastic or wood down in to it. Arrange it like a squared U
shape.

That's right John, that's exactly what I want to do.