I had spoken to Mark a few months back about my plans on trying to use the Edge Pro Apex for convex sharpening,
when I ordered it from him. I promised I would post my findings on here.
Here goes:It is very easy to use the EP for convex sharpening!
I use mine primarily for just that!
Some people may ask why one would want to do this, but I think it's a no-brainer, since the EP allows for very exact bevels.
I rarely need to use the guide plate, since convex sharpening with a padded abrasive is more forgiving than when sharpening with a stone.
The reason for this is because the padding compensates for small errors, in that it curves to the bevel, whereas a stone does not.
Having said that, using the guide plate is always better and much more precise, but the lazy way out is to not use it (and risk getting poorer results).
So, basically all that is needed to do this at home is:
*A blank EP plate
*Double-sided tape (strong bond. If possible — not with water based glue)
*A cut-to-size padded backing, such as a mousepad (but harder backings work much better)
*Sandpaper which has been cut to size with an Exacto and a ruler (preferably wet sandpaper)
There are many different types of sandpaper, tapes and backings around and not all work very well, whereas some excel at the task. TAPE
I personally like a stronger double-sided tape, since it doesn't get loose when wet (regular office supply ones seem to do so, but work fine).
Remember that you will be applying force, so the paper may get loose, just as the regular 2000/3000/6000 EP-tapes do sometimes.
Fabric sandpaper seems to stick poorly to regular double-sided office tape. If the glue of the tape is too strong though and your sandpaper-backing is made of paper,
it may be difficult to remove the sandpaper and reuse the tape without tearing the paper, so be prepared to use a bunch of tape or experiment with different supplies.BACKING
I use several, which I've cut to size. Permanent Spray Mount (3M) bonded it to the blank plate, but double-sided tape works too.
You can probably find your backing at a rubber- and hose supply store. I use a softer one (stiffer than a mousepad though) for grinding and chopping tools.
The hardest one I could find was made of natural rubber, which is a bit expensive; but, it's almost like sharpening on hard leather.
I found another one which is sort of in between and it is just right for me (some sort of plastic rubber).
It is important to get the right amount of give in the backing, especially if you want to get hair-whittling sharp edges.
If the backing is too soft, such as most mousepad are, then it is very easy to round the edge and it becomes harder to get it scary sharp.
Remember that the backing should be easy to clean, unless you want to make new backings all the time.SANDPAPER
I only use wet sandpaper and a toothbrush (to spread 2-5 water drops evenly), so as not to get metal dust in my lungs.
The sandpaper should not have a slick woven fabric backing, as it doesn't stick very well to the tape (but use it if you like).
Cut the sandpaper into strips which won't extend over the backing, since sandpaper edges cut just as well as a knife does, especially on higher grits.
The sandpaper can cut the support-hand index finger easily when working around the heel of the knife.PROTECTION
I try to wear breathing protection, as I've noticed that when the sandpaper becomes filled with metal and loosened particles,
that dust-buildup sometimes goes airborne when I remove the strips and so on. Eye protection (glasses) is a good idea too,
especially when grinding (particles may splash all over).
I've sharpened and honed a plethora of different knives with the convex method now and it works very well!
I'm talking folders and fixed blades, convex edges and full zero-grind convex blades of all shapes and sizes.
Full convex zero-grind blades require a raised triangular block on the guide (to get a lower angle), or balancing freehand on the edge of the EP.
The convex sharpening modification works!
Here are some pics of my setup. I figured I'd show you my Cold Steel Gurkha Kukri (SK-5) which I convexed on the EP Apex.
I chose to show you this one in order to illustrate that even the most difficult blades are easily sharpened with this method.
The grits I used were: 120/240/400/1200/3000/6000. It is extremely sharp now. The pic makes it look satin finished, but it is almost mirror polished.