Foil adhesion

The almost universal recommendation to grind edges so the foil adhesive can make a good connection is incorrect.

The adhesive on foil is an impact adhesive, which sticks best to smooth surfaces.

It is not possible for a thin film of adhesive to fill any roughness on the glass, so it adheres best to the clean and smooth parts of the glass. If you have to grind, finish with the fine grit on your grinder. That's why some copper foilers have two grinders – one with a standard grit, and one with a fine grit.

Excellent cleaning of a ground edge is also necessary for a good adhesion of the foil to the glass.

The only plausible reason the foil stays on glass with ground edges is because of the overlap of the foil onto the smooth surfaces on top and bottom of the glass. This is why burnishing the surface faces is so important. No amount of burnishing of the foil to rough surfaces will make it stick well.

If the scoring is accurate, no grinding should be done, because the foil will stick very well to the smooth edge. It may be advisable to smooth off any shells or hanging edges, but without grinding the whole edge.