If you use a sandpaper on glass sharpening method you’re well aware of the process involved in maintaining the sandpaper. From often changes to tiny tears due to ripples created when tiny pockets of air get trapped underneath the paper. I’ve discovered a few tricks to help eliminate these ‘bubbles’ between the paper and glass and generally highten the odds of achieveing great sharpening results.
The first step when applying the paper to the glass is being sure the glass is completely clean and free of any small dust particles. I generally rub a small amount of mineral spirits over the glass with a clean shop towel, this not only gets rid of small amounts of dirt and grit it penetrates any of the sticky residue left behind from the previous adhesive backed paper. Once you have the glass clean, cut your paper to size and apply a small drop of water with a little dish detergent in it. Just a drop is all that’s needed to allow the paper to move around ever so slightly while applying. Peel off the paper backing and apply. The best way to get rid of the air bubbles from underneath is with a burnishing tool of some kind; this is where your honing jig comes in handy. What better way to get rid of these little pockets than to use the heavy brass roller that comes standard on the Veritas® Mk.II Honing Guide. Just tip it back a little so the front lip is clear and, while pressing down firmly push any air out from each edge of the sandpaper.
Oncet the paper is applied, it’s time to sharpen. I always like to add some oil to the paper, this will quickly work itself into a slurry when you start to wear off metal from your iron. Clear machine oil is available or you can try using household baby oil available in every drug store around. To reach favourable results I find a good amount of downwards force is required on the blades leading edge. To achieve this and maintain stability, I will often turn the honing guide around and draw it towards me, not unlike the motion of using a Japanese hand plane. This will allow you to use your thumbs for added downwards pressure and gives you a lot more control over applied sections of the Irons edge. IE: honing a slight camber into the outside edges of a smoothing plane. The Mk.II is a sure fire way to get favourable repeated results when sharpening and these couple of tricks can get you closer to that perfect edge.
Remember, it can never be too sharp!