New strop material

G

Greg

Joined
Jul 15, 2004
Messages
761
For a while I've been disappointed with leather as a strop material. Even bonded to a hard base the leather 'gives' and this eventually rounds the edge. To avoid this I usually strop at a lesser angle than the main bevel, and have to strop for many light strokes.

I want to be able to strop *hard* so the strop also acts somewhat like a steel, but doesn't put great lateral pressure on the edge and cause chipping or distortion. I've tried paper on glass but couldn't get a good edge.

Yesterday I was sharpening a knife for a friend and wanted to give her a 'maintenance tool' so she could keep the polished edge razor sharp. As I polished the edge using a paper wheel I thought "What about a bit of wood to hold the polishing compound? If it works for the wheel, it should work for a strop. That'll be harder than leather, softer than glass, and if I get it the right size, will be easily portable. Hmmmm."

So I hunted around the shed until I found a sheet of 15mm 'craftwood', the same stuff that paper wheels are made of. (If it's not the same in the US, it is also known as MDF.) I cut a piece about 3/4" wide and six inches long. I put coarse polishing compound on one side and ultra fine on the opposite.

I finished the edge, testing my new tool by using the dressed wood like a file. I put a very small micro-bevel on the edge only a couple of degrees more obtuse than the main bevel, AND ENDED UP WITH THE SHARPEST EDGE I'VE EVER MANAGED!

I have a new sharpening tool. Give it a try and tell me how it works for you. I'm not going back to leather strops.

Greg
 
Sounds like a great idea, I know I have some MDF out in the shop and will give it a try. One of the drawbacks of MDF is that it dulls a saw blade quicker than wood, so it seems logical that it would have some abrasive properties. Thanks for the tip.-Dave
 
That is cool. I was thinking of trying to rub some compound on a dollar store poly cutting board, but MDF might be even better. In fact, I think I have some birch plywood left over from making my bench strop that could do the trick. Heck, I might even have some hardboard I could use to see if there's much difference between the smooth and rough sides.
 
Wonderful idea. I'll give it a try. What is the advantage of MDF over an 8" piece of 2x4, flattened, edges rounded, and dressed with .5mm Chromium Oxide or Thiers-Issard paste?

Buzz
 
buzzard767 said:
What is the advantage of MDF over an 8" piece of 2x4, flattened, edges rounded, and dressed with .5mm Chromium Oxide or Thiers-Issard paste?
Click to expand...

I think you're still supposed to charge the MDF as you would the 2x4 or leather with that Thiers-Issard stuff. The only conceivable advantage in my fevered brain is that MDF might be less likely to expand or contract along prominent grain boundaries like wood might.

Some of the "need it spooky sharp and need it quick!" woodworkers use flattened cast iron with tiny grooves to hold diamond slurry. Not sure how that'd play out with knives and definetely wouldn't try sharpening a recurve that way.

Thanks for the tip, Greg!
 
buzzard767 said:
Wonderful idea. I'll give it a try. What is the advantage of MDF over an 8" piece of 2x4, flattened, edges rounded, and dressed with .5mm Chromium Oxide or Thiers-Issard paste?

Buzz
Click to expand...

I honestly can't see much difference other that the different hardnesses along the grain boundaries.

I used the MDF because I know the 'texture' of the surface is consistent and holds finishes like paint extremely well. So I figured it would hold polishing compound too. As well, my paper wheel appears to be made of MDF and that has revolutionised my sharpening over the last couple of years.

Unlike leather, the hard surface allows me really precise control over the bevel angles, so I can hone and polish for as many strokes as needed without rounding the edge.

I've now tried this strop on my primary kitchen knife and it works well there too. I'm still amazed by the final edge it is putting on what I thought were very sharp pocket knives and my EDC fixed blades. I may have to buy some diamond paste and try that.

Does anyone have a recommendation for a diamond preparation that goes on the strop very smoothly, and what size would give the best polish? I think my obsession is showing!

Greg
 
Greg said:
Does anyone have a recommendation for a diamond preparation that goes on the strop very smoothly, and what size would give the best polish? I think my obsession is showing!
Greg
Click to expand...

I bought some 1, 1/2, and 1/4 micron diamond pastes from MTI at:
http://www.mtixtl.com/index.asp. I used their search window for:
Diamond Compound Polishing Paste

Thinning the pastes (just a small amount!) with ordinary mineral spirits (paint thinner) allowed even charging on my leather belts, and unlike mineral oil, didn't cause stretch. Just allow an hour or so to dry thoroughly before use.

Use a delicate touch with the 1/4 micron stuff, and it's just the thing for the microtome you use to slice samples for your electron microscope.:D
 
I tried this and then return back to leather. Most important it should not be glued to something but rather stretched over, so it moves with blade if you apply too much pressure by accident.

Here it is:

http://www.youtube.com/watch?v=3WY8rhecws8

I have it for Green Rouge and for diamond powders (in sprey).

Thanks, Vassili.
 
nozh2002 said:
I tried this and then return back to leather. Most important it should not be glued to something but rather stretched over, so it moves with blade if you apply too much pressure by accident.
Thanks, Vassili.
Click to expand...

Vassili,

If I decide to try another leather strop I will go for stretched and see what difference that makes. Thanks for the idea, although I still think there will be 'give' in the leather.

What made you give up on the MDF? I read the thread posted by
hardheart above, and it seems like you got excellent results. What changed?

Also, if the videos are accurate, you don't polish the bevel. I like mine mirror polished with a very smooth edge and am wondering if this might make a difference.

Because I usually only sharpen for myself I'm not fussed if it takes a while.

Greg
 
I tried paste on glass. On paper backed by glass. On a 2X4. On waxed paper backed by glass. On Masonite( hardboard.)

And now I use it on leather strops only. :thumbup: The other stuff may work very well for you. :) By all means give it a try !

Leather works for me!:)
 
Greg said:
Vassili,

If I decide to try another leather strop I will go for stretched and see what difference that makes. Thanks for the idea, although I still think there will be 'give' in the leather.

What made you give up on the MDF? I read the thread posted by
hardheart above, and it seems like you got excellent results. What changed?

Also, if the videos are accurate, you don't polish the bevel. I like mine mirror polished with a very smooth edge and am wondering if this might make a difference.

Because I usually only sharpen for myself I'm not fussed if it takes a while.

Greg
Click to expand...

I use thin leather and it also prevent edge from rolling over.

I gave up on MDF because it dusty, and when I sharpen I have my face right near to see results and breeze this dust. There is also HDF but surface not too flat.

I had better results, but still it was luck and does not work consistent enough for me - like 40% success. Thin stretched leather more forgiving I think and absorbs some wrong moves. One way or another but it works 100% success for me.

Thanks, Vassili.
 
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