07-10-2018, 12:10 PM
Steve, I sourced my plywood, never more than 3mm, from a local firm repairing vintage aircraft and gliders. It is graded according to defects in the surface A,B,C or D . So AA would be the best BOTH sides and DD the worst. For a trim panel that is to be covered and unseen BC or BD would be OK. Exterior grade glue is more important than a few knots or filler.
I googled Aircraft plywood 3mm UK and came up with many options local to you .
Gymp pins, (the small headed ones), japanned, nickle or brass do look the part but can be difficult to remove when you need access to the window winder or door locks for service. Common practice is to use nickle plated cup washers with raised head countersunk slotted wood screws. To reduce their impact minimize the number and size used, never larger than #4 and say 9" apart. I use a countersunk washer that does not have a return so it remains invisible behind the screw head but works to provide the necessary slippage against the fabric. Oh and avoid the common mistake of overpadding, 3mm or NOTHING is good, good luck , cheers Russell
I googled Aircraft plywood 3mm UK and came up with many options local to you .
Gymp pins, (the small headed ones), japanned, nickle or brass do look the part but can be difficult to remove when you need access to the window winder or door locks for service. Common practice is to use nickle plated cup washers with raised head countersunk slotted wood screws. To reduce their impact minimize the number and size used, never larger than #4 and say 9" apart. I use a countersunk washer that does not have a return so it remains invisible behind the screw head but works to provide the necessary slippage against the fabric. Oh and avoid the common mistake of overpadding, 3mm or NOTHING is good, good luck , cheers Russell