How can I reconstitute the rotted wooden horizontal of a window that I need to bodge before replacement in a couple of years?

I'm thinking something like fibreglass around something but don't have any more ideas than that. Doing the job properly at this stage by replacing the windows or replacing the piece of wood is not an option - can anyone help.

Heather, June 2007

You're welcome.

Big Softy, June 2007

Thank you, that's brilliant I'm going to get some tomorrow!

Heather, June 2007

Ronseal do a wet wood rot hardener, B&Q stock it.
Remove any powdery timber, do what it says on the tin, then fill, sand, and seal.

Big Softy, June 2007