 | Quote: |  | | |  |
Originally Posted by gillystyle |  | | | | | | | | | can pinholes be caused by a dirty rubber blanket on my burn unit? if so, is there a way that i can clean this blanket? can it be removed and pressure washed for example? a little help...?? | |  | |  | |
Yes, dirt on the positive or glass can cause pinholes, but that is screen making homicide and an autopsy can determine that.
I want you to focus on a too thin coating that fails and lets ink transfer through the mesh.
Coating
Most emulsions average 35% to 45% solids which means 60% water that has to evaporate from the coating for the best exposure results.
A sharp lip trough & 1x1 coating does not fill the holes.
The emulsion shrinks as it dries and takes on the shape & texture of the mesh. In the open areas of the mesh, the stencil gets much thinner. Future pinholes.
This creates dimples in the surface that can break and cause pinholes if the dried emulsion is too thin to bridge the mesh holes.
Low-solids content emulsions shrink excessively and are sometimes prone to this problem.
You can judge if you have filled the holes by looking at the inside of the screen and if you don't see a glossy finish on the inside, you haven't filled the holes yet.
Coating FAQ of Screen Making Products
problems with pinholes 
