...My question is can you use this method to sharpen any grind, or is this method exclusive to convex blades.......
"Yes" and "no."
"yes," you can sharpen any grind "like this,: and "no," it is not exclusive to covex grinds. Omit the mouse pad and substitute the bottom of your Altoids tin to provide a stiff, flat platten for "other" grinds. Sharpening chisels and plane irons on abrasive paper - on a piece of "plate" glass has been very popular for a long time and it has all the benefits of a new, flat stone, plus some. People are fanatical about those types of edges being "perfectly flat" and this method achieves the level of flatness desired. If one wishes to face reality and admit that "no man's hand is a sharpening fixture," one will realize that, even a true Scandi becomes something of a convex eventually, especially in the field - so,... at your own discretion, you could also opt for a thin cork or leather backer for your paper for your flat grinds, Scadi's, etc. Try it on a $10 Mora and see what you think of the edge you can get. You may be looked dowon upon by some dyed in the wool Scandi fans but you will have one very sharp knnife with a durable edge that you can achieve at the bench or sitting on a log and without 40 years of experience.
My personal field sharpener is just a small version (1" by 6") of my "bench models," (which are 3" by 12") - set up for plane irons and chisels, as well as my knives. I use a two-sided leather strop with
Mibro "#2" on the "coarse" (actually still very fine), which is somewhat aggressive but turns a fine, even burr on even the fanciest, hardest steel I have rather quickly and easily. On the "fine" side, I use
Dico "WR1" with an ever-so-slightly higher angle and a lighter touch - as you described, you can "hear" when you hit the correct angle. The Green Mibro "#2" is aggressive enough that I don't need paper unless I do something stupid (like batoning a BRKT Canadian Special though an embeded stone
, like I did once) so you can carry some paper "loose" in your kit and hold it over the leather of your strop or the cork/leather glued to the bottom of your Altoids tin in addition to the mousepad you already have.
But, back to the original question - "yes" these materials are excellent for "other" grinds, You just have to make some adjustments in use and some other materials. One way to experiment and find what materials and methods are right for you is to invest in a $10 Mora and "play." The key is that all you are trying to achieve is to remove material right at the edge, evenly on both sides and consistently along the edge at an angle that leaves a suitably strong/durable edge that is still acute enough that you don't have extra blade material wedging itself in the cut ("kerf," so to speak) as it follows the sharp edge. Keeping the "side" of the edge in contact with the abrasive is what makes things happen and NOT doing so (or using too steep and angle) is what frustrates people. Knowing exactly WHERE the edge is on a convex blade can be more a matter of "feeling," hearing, or, if you are using a lubricant, seeing (bubbles form in light, light oils on abrasive paper following the edge as it passes over the abrasive). You can also put an effective convex on a Mora starting with 320 grit and working "up" to play arouind with a convex edge without worrying about what you are doing to an expensive knife. The poor Mora. It stands in for the dirty work sometimes but it's a sweetheart all the same.
. I think you could use it for any grind, but you are right that it would "convex" the end result. It seems to me that if the soft mouse pad concept were replaced with something firm (hard) then you could also touch up other grinds with straight/flat bevels without rounding them. I suspect the difference is really if you just need to touch up an edge in the field or want to be able to do a more in-depth profiling...meaning the harder material would not be very detrimental to a convex grind if used as a touch up, followed by the leather strop.
