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Hi,
I'm going to have try with this stuff, just received a sample pack with lots of different grits from 100 microns down to 0.3. Has anyone else used this? I'm wondering whether to stick it down to pieces of hardwood, or whether it really needs to be on glass. The supplier mainly deals with woodworking tools so they're expecting you to stick a selection of grades onto a sheet of glass, but for knife use it's a bit more difficult to arrange because the abrasive needs to go right to the edge.
If anyone has used these products, what were the most useful grits, and were they used...
An introductory summary:
SharpoSharp (
https://sharposharp.com/) sent me some “Precision Grade Sharpening Film” to try (see
https://sharposharp.com/pages/available-sharpening-films). There are three different products:
- Aluminum Oxide Lapping Film with 8 different grits from 40 to 0.3 micron; about $4 per 8.5x11" sheet. Thinner more flexible backing good for 5-8 uses.
- Aluminum Oxide Micro-finishing Film with 8 different grits from 80 to 9 micron; about $6.90 per 8.5x11" sheet. Has a heavier more durable backing than the Lapping Film good for 7-12 uses.
- Diamond Lapping Film with 10 different grits from 80 to 0.5 micron; about $9.60 per 8.5x11" sheet. Uses aggressive diamonds good for 10-20 uses.
After using these for two months I can say that I like them more than I expected. A few things that I like specifically about these:
It is recommended that you
do not flatten water stones using sand paper because the grit can break off and embed in the stone. The resin bond in these films seem to hold the grit stronger than my sandpaper so I would be less concerned about using these to flatten my water stones; but I own many diamond plates so I use that.
I recently acquired a JORGENSEN Chamfer Plane (see
https://www.amazon.com/dp/B0CZDSF7HR) with three cutters that I need to sharpen the inner portion using either appropriately sized files or by wrapping “sandpaper” around a dowel. The Aluminum Oxide Lapping Film is thin and flexible so it works well even with a tight radius.
The Diamond Lapping Film is my favorite and boy does it cut, especially the 180 grit (80 micron) film. Honestly, all of the films start very sharp and work well, but the Diamond feels sharper and faster to me. I have an 80 grit diamond stone for my Hapstone fixed angle sharpener, and I think that I am cutting faster with a fresh 180 grit Diamond Lapping Film.
I still have more testing to perform since most of the steel that I have sharpened has not been super steel because my blades with the super steels are still very sharp. So the toughest steel that I have sharpened is S30V and S35V on kitchen knives that I own (
https://warthercutlery.com/). Apart from that it has been Case pocket knives (relatively soft steel,
https://caseknives.com/), older Gerber Chef knives and Henkel Chef Knives (
https://www.henckels.com/us/knives/chef). I did not include a link to the Gerber knives because these have not been in production for a while and the best I could link to is an eBay listing.
I used Wedgek angle guides (
https://angleguide.com/ or
https://www.amazon.com/dp/B08L5D67GD or
https://www.amazon.com/dp/B07NF1RYXV). The first link takes you to the official web site and they have calculators if you want to calculate what angle to use based on things such as existing bevel angle, sharpening angle, and blade thickness. I used the angle guides as a reference angle and then sharpened by hand.
My process was as follows:
Take a full size sheet (because I had 8.5x11 sheets
https://sharposharp.com/products/diamond-sharpening-film-complete-set?variant=42285901349017) and I cut them to width to match their plate glass and put the glass into the holder (
https://sharposharp.com/products/stainless-steel-rubber-base-with-glass). The glass is thick enough that it sticks up above the the holder sufficiently that it does not catch.
You do not need to, but, I like to use this wet so I spritzed the film with water and then sharpened by hand.
I did shoot video while I did this, but frankly it is not very exciting to watch. I will say, however, that I was really impressed by how well this worked. I was able to very quickly re-establish edges and it was cutting much faster than I am used to. For the most part I was not reprofiling, but the knives that I had not previously sharpened (like the Case Seahorse Whittler
https://caseknives.com/products/smooth-red-synthetic-american-workman-cs-seahorse-whittler, I own a few of these) were not consistent side to side or even across the same side on some blades. I believe that they sharpen by hand using a belt.
I started sharpening using sandpaper because I had nothing else. I sometimes even flatten chisel backs and plane blades on sandpaper when they are really bad. This film is a much better solution to sandpaper.
I will admit that I was careless a few times and I was able to use edge leading a few times…. Until I apexed the edge. So, do not become complacent, just use edge trailing even if using both is faster. It is faster until you are apexed and try to cut into the film.
So, highly recommended.
