I am looking for any unfinished uPVC with a square or rectangular section to glue into the corner between two uPVC panels to reinforce the joint. The two panels I plan to glue together are 1.7m long, so ideally I am looking for one or more bits of uPVC that add up to at least 1m, which I will glue to hold the two panels together in a right angle. Any cross-section from perhaps 1cm to 3cm or 4cm or so should be workable. Your uPVC should have a smooth finish too so I can make a good chemical bond with a suitable uPVC adhesive.

I am renewing a fascia board above a 3-section uPVC window.

Grateful for anything you have.