In article ,
Michael McNeil wrote:
I think the box section acetate stuff is the same as the
material used in crash helmets and is bullet proof to some
extent.

Polycarbonate not acetate. Hopefully the bullet resistance is
not of importance to the OP g

A problem with poor fitting practice is creepy crawlies. So
always get the end barriers and use them.

You need to seal them with silicon: the problem my mum found
(too late) is that if the cavities are not airtight you get
condensation which then leads to unsightly mould growth

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