I wonder if anyone can offer advice about using open weave lattice sinamay as a blocked shape.  I am trying to make a particular design saucer headpiece where I only want a single thickness of lattice sinamay in the brim. I have blocked it and wired it successfully with my usual amount of PVA stiffener. I plan to add a central silk covered button shape on top of the saucer and a small firm sinamay base under neath onto which my head band or hat elastic can be fixed - so the lattice part will be sandwiched between the two. I do not want the saucer to sag in the middle and really want it to be very stiff.  Is there a way of spraying on or painting something like black gloss paint or varnish?  If so can anyone recommend a product available in the UK.?  Any help will be much appreciated please.