Good day, r/sharpening. I'm looking to keep leather working knives sharp. I have some Kiridashi and some flat Japanese style leathercraft blades. They're made of soft-iron clad Aogami/Shirogami 2. I'd love to try thinning and/or rebeveling one of my Kiridashi so I'd like to have a range of grits, but I'll worry about that once I find a solution I like.
My research has led me to believe diamond lapping film may be a good way to do this. I've been sharpening on some AO PSA films but they take forever to cut and they wear out quickly. God forbid I have to repair a chip; goodbye to the sheet and I'll be there all day. All that time spent grinding has been good practice though, because now I feel pretty good about my freehand technique on single bevel blades. My knives seem to be preforming well, but I can tell they're not at their best. I just thought lapping films might be a good fit because I won't need to be sharpening all that frequently; my knives can get through about four projects before they start to lose their edge. I'm just a hobbyist so that takes me a while.
I've only been able to find 3M Diamond PSA by the sheet here (US Retailer). That's 13.99 USD per 8 inch x 3 inch sheet, and I was thinking of getting maybe 3 different grits just to test em out. I have no idea if that's a fair price, but it seems reasonable compared to a set of 3 Shapton stones of similar grit. I haven't been able to locate another source for per-sheet 3M diamond films so if anyone knows of any, please let me know. I can find plenty of industrial scale retailers selling cases of the stuff, though.
Do the downsides of PSA films (fragility, shorter life span, others I'm not aware of) make investing in stones worth the higher cost of entry? Is it true that lapping films can cause round-over problems at coarser grits, even on a "dead flat" surface? Do the films deform/compress under sharpening pressure or something? I tried to do as much research as possible before making a post, but I still can't make up my mind. Any thoughts you all could share would be greatly appreciated. Thank you for your time and for reading this essay.