about to convex my first blade what do i need???

Allen R.

Allen R.

Joined
Nov 1, 2011
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I'm heading to the hardware store now to get materials to convex some edges , I know I need wet dry sand paper and a mouse pad, what grits should I get ??? And am I forgetting anything as well???
 
I actually use a whetstone or water stone to convex, then the belt/hand sanding and stropping. Convexing is just knocking the shoulder off. If you don't have a belt sander a moderately aggressive whetstone would work.
 
I've got a diamond stone but it flattens my waterstones SBD the grit well is not that coarse Imma give the sand paper a try
 
wd40 will keep your sand paper from clotting esp in the higher grit.... though soap and water work just fine =)
 
(Personally, I'd avoid the mouse pad. It's too soft, and tends to be a source of frustration when trying to learn convexing, rounding edges if not very careful. I prefer a thin layer of firm leather, over wood backing.)

Wet/dry sandpaper in the 220-600 grit range should be a good start. Conveniently, these grits are most widely available at most home centers & hardware stores. A flat & smooth piece of wood as the backing for the paper is a plus. Home centers often carry some 'project' or 'hobby/craft' cuts of poplar wood or oak in convenient widths for a strop block, and in lengths from 2' and longer. Some contact cement or double-sided carpet tape (2-1/2" width) can be used to stick some leather to the wood. If leather isn't conveniently available, a layer or two of fabric like denim, or a few thicknesses of printer/copy paper in between the sandpaper and wood will suffice as a forgiving substrate to create some convex in the shoulders of the edge grind. As mentioned, this can be done on a stone, but usually takes some getting used to, if you haven't done this before.

The leather, sandpaper and wood can be 'assembled' into a handy convexing & strop block, as seen in the pics below. The sandpaper can be cut to width and wrapped around the block ends and taped, also as shown below. In that example, I used 2-1/2" wide red oak (1/2" thickness) as purchased & described above, with the the 2-1/2" wide carpet tape to stick the leather on. Obviously, the length can be tailored to preference; I sized mine to use 'freehand', held as seen in the 2nd pic below.

For stropping, some black, white or green buffing compound (or all three) can be found in the tools section of most hardware stores/home centers.

This is just one way to start, but it works. :)


David
 
Last edited:
RemyKaze said:
I actually use a whetstone or water stone to convex, then the belt/hand sanding and stropping. Convexing is just knocking the shoulder off. If you don't have a belt sander a moderately aggressive whetstone would work.
Click to expand...

This. Whether or not it's actually convex or "facet cut" as a series of flat bevels doesn't matter so much. It's really the reduction of material behind the edge that improves performance.
 
I highly recommend using a hard stone/surface of some sort, and only moving to something with some give after you've roughed in the arc. This will help makes sure your convex is nice and shallow with an acute finish. I'd make a series of lines with a Sharpie going from spine to apex so you can see right where you're grinding. Three or four sheets of paper wrapped around the stone and dosed with compound will smooth out any variation in grinding facets.
 
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