Good evening

Dose anyone happen to know what material the seat cowl is made of. I’m currently cutting one up for a build and to make some modifications in shape and size. Making it narrower but before I buy an epoxy/fiberglass or automotive resin I want to be sure it will adhere. i really like the shape but it’s too  wide for my tail.

It's proprietory to BMW and they call it Fibron. It's a very high density sandwich of polyester resins, stranded fiberglass and fillers (usually marble dust!). It can be modified/repaired with epoxy resins but you might want to consider using something like fiberglass drywall tape to hold things together first (get it off Amazon as I'm not sure it's off the shelf here in the UK) and then a normal fibreglass mat to build it up. I did repair a broken tail unit (one side snapped off by Hermes) but I fitted a 1.5mm stainless plate along the break before applying glassfibre/epoxy. I used 3mm dome-head allen screws with form G ('penny') washers on the other side of the join. Given the amount of pressure and abuse a seat unit takes, I didn't trust just a glassfibre repair.

Amazing thank you Dai!! You are truly a fountain of knowledge!!!

You can make a safe bet that I learned the composition from someone else on this forum. I also meant to mention that I glued as well as screwed the stainless strip to the underside of the seat unit.