Ditto my reply in (2).
For future reference, apart from metal mesh sheets, there is also 'Sylon' mesh, which is available in very fine grades, measured in microns. It's the same stuff as used in very fine filters, such a carburettors and fuel filters, and some house hold items, for example, fine kitchen sieves, wine strainers, and the 'fluff filter' in tumble driers.Easy to cut and glue, although the edges can be a bit ragged on some of the larger micron types.
Oh, oh ! There goes Geo, stripping down the fuel system on his neighbour's car !