Hi there, I was wondering if anyone had experience of the foil backed insulation board?

I have used it quite a lot for quick & dirty plug making for boat parts & models, it is ok with polyester & doesnt mind the exotherm.
It can be used to make buoyancy blocks for boats if its covered with a thin layer of glass cloth or csm.
However the stuff is very weak & friable & has virtually no shear strength so dont be tempted to use it for anything thats structural. If using in boats remember if its punctured it will blot water up quite quickly.
Harder heavier grades are available specifically for plug making but obviousaly will cost more.