Sandpaper question

E

Etap73

Joined
May 1, 2015
Messages
18
Hello,

Had a question about a sandpaper set up I've been trying. I went to Lowe's and got 4 3"x12" polished marble tiles. Then using light spray tack affixed 220 grit, 600, 1200 and 2000. I'm relatively new to hand sharpening but I've had good luck with oilstones and stroping with paper, but wanted something beyond an India stone.

. The question is that from threads on this forum and YouTube videos I thought that the sand paper would last longer but it seems to lose a good bit of its grip almost instantly as I start to sharpen. I've tried using edge trailing strokes only but it doesn't seem to matter between edge trailing or edge leading. I've also used an eraser to try and clean the sandpaper and keep it from loading up. (Heavy-handed videos) Its worse at the coarser grits.

I'm using 3m wet/dry from an automotive store.

Any thoughts?
 
I use klingspor or every other top shelf sandpaper -Aluminum Oxide Cloth Sheets- they last long and hold very good, like emery cloth.

At the lower grits I recommend on Cloth Sheets with AO.
 
Most likely you are using too much pressure - should be a very light touch, let the abrasive do the work. Also, the sandpapers will experience an initial break in where they feel like they have lost a bunch of abrasive action - they have, but the resulting surface is the true one and it will/should /can/might last a long time if you keep it clean and use with light amounts of force.

If after a short break in, the sheet you're working on isn't getting the job done you need to go to a rougher grit. 80 is the lowest I'd recommend, with 120 able to handle most angle changes and rough clean up. I mention this in one of my videos, is the Achilles heel of all sandpaper systems that you cannot just apply more pressure to overcome slow grinding at any given stage.
 
HeavyHanded said:
Most likely you are using too much pressure - should be a very light touch, let the abrasive do the work. Also, the sandpapers will experience an initial break in where they feel like they have lost a bunch of abrasive action - they have, but the resulting surface is the true one and it will/should /can/might last a long time if you keep it clean and use with light amounts of force.

If after a short break in, the sheet you're working on isn't getting the job done you need to go to a rougher grit. 80 is the lowest I'd recommend, with 120 able to handle most angle changes and rough clean up. I mention this in one of my videos, is the Achilles heel of all sandpaper systems that you cannot just apply more pressure to overcome slow grinding at any given stage.
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:thumbup:

Etap73 said:
Hello,

Had a question about a sandpaper set up I've been trying. I went to Lowe's and got 4 3"x12" polished marble tiles. Then using light spray tack affixed 220 grit, 600, 1200 and 2000. I'm relatively new to hand sharpening but I've had good luck with oilstones and stroping with paper, but wanted something beyond an India stone.

. The question is that from threads on this forum and YouTube videos I thought that the sand paper would last longer but it seems to lose a good bit of its grip almost instantly as I start to sharpen. I've tried using edge trailing strokes only but it doesn't seem to matter between edge trailing or edge leading. I've also used an eraser to try and clean the sandpaper and keep it from loading up. (Heavy-handed videos) Its worse at the coarser grits.

I'm using 3m wet/dry from an automotive store.

Any thoughts?
Click to expand...

Might also look into some aluminum oxide papers in the high-durability pink/purple varieties (3M/Norton brands), found at Lowe's/HomeDepot/etc. For the heavier grinding in early stages, I've noticed they'll last a good while. As Martin mentioned, by touch they'll feel like they've worn quite a bit, but they just keep grinding away. Most of those are available in coarser grits from ~80 up to maybe ~320 or so; anything from about 120/150-grit and up can work well for heavy grinding on knives; I'd avoid the very coarse ones for grinding edges on blades, though they could be useful for doing things like re-shaping a spine on a heavy blade (such as for re-tipping a broken blade).

I've also used sanding belts in aluminum oxide; I cut them at the diagonal 'seam' in the belt, and then tack them down to a hard surface as you've done. Those are also quite durable. I used one of these at 120-grit to re-shape the tip on a Buck stockman's spey blade, as mentioned above.

The SiC wet/dry papers are at their very best in the mid-to-finishing grades (maybe from ~320 and up), and will keep working a long while when used as Martin has suggested, with minimal/light pressure (and edge-trailing only; edge-leading will tend to dig more abrasive off the paper). The grit keeps working, but the finish will become more refined/polished as the paper wears a bit. For lifting the clogging swarf from the paper, I've also found a microfiber towel works very well for that; the swarf really clings to it, even when used dry. The yellow microfiber towels found at Costco are what I've been using; might also find those in the automotive finishing stores, or in equivalent sections at stores like Walmart, etc.


David
 
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Thanks for all the feed back, I've really tried to use the lightest pressure possible. I think at first I was definitely over pressuring. I will try using lower grits for damaged blades.

Would it be better to use stones at lower grits, then switch to sandpaper to refine the edges?
 
Etap73 said:
Thanks for all the feed back, I've really tried to use the lightest pressure possible. I think at first I was definitely over pressuring. I will try using lower grits for damaged blades.

Would it be better to use stones at lower grits, then switch to sandpaper to refine the edges?
Click to expand...

No harm in that, if you're comfortable with stones. A lot of the edges I've done started out by grinding new, crisp bevels on hard hones at more acute geometry (to establish a good foundation for the edge), then following by refining on sandpaper; usually at ~320-grit and up.


David
 
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If doing a ton of work lowering angles or thinning primary grinds, solid stones might be a better choice. An XXC DMT plate can do a lot of work offhand.

A lot of it comes down to what sort of grit progression you need, and that's something you'll have to feel out whether using stones or flexible media. 120 grit SIC wet/dry with a light touch can gently remove a lot of steel and make progressing to finer grit fairly easy.

Feeling out abrasives one is not familiar with, and perhaps even becoming familiar with the mechanics of freehand sharpening on said abrasives, I'd make sure to practice on expendable knives. That way you can push to extremes different angle approaches etc, learn what its like to over and under shoot and how it effects the edge visually. When you go after cutlery you care about will be with a lot more confidence - you will have answered many of your own questions. Wet/dry is very inexpensive...
 
Once again thanks for the great information. I do well but it's as if I opened Pandoras box with this sharpening thing. I will take the advice to heart, especially different grit progressions with different steels. Some of my knives are cheap but it takes guts with the little experience I have to tackle the few expensive customs I have. (a friend from work has an incredible edc fixed blade tanto made of Damascus steel that he uses from cutting game to cutting Geo fabric in dirt he wants me to sharpen)! Not comfortable tackling that yet!

The main thing for me is to not throwing out too much money yet. I'm ready to buy a full set of chosera stones right now but figure i better get the hang of what I'm doing before spending money! Haha
 
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