A strop for carving tools needs a very fine surface for accepting compound – yet is thin enough to not cause gross rounding of the micro bevel. I go through lots of hides at my leather wholesaler before I chose the ones that have a knap and thickness that is ideal.
When you get a new strop it will need a bit of preparation. Take the sharpening compound and rub it diligently into the leather – about 50 strokes around the entire surface, pushing down fairly hard, to work the compound into the leather. Commence with stropping a few tools, watching for ‘dry’ spots that will inevitably appear. Rub in more compound there, strop tools, repeat….. until it has an even appearance. Before long it will need very little compound re-applied. Long term I re-apply just a couple of strokes of compound after every 4 or 5 heavy uses.
Compound for strops is a formula of super fine abrasive powder mixed with various waxes. Sometimes called ‘rouge’ it can be confused with jewelers’ rouge, (which is generally made of very mild abrasives good for only gold and silver, not for hard steel).
There are many brands of compound to choose from that can work well. We have chosen “White Gold” to offer our customers because it is formulated specifically for hand stropping – it polishes the edge while micro sharpening it. If you have another type of compound, just check that the leather is turning black as you strop – this indicates that the compound is hard enough to be removing metal – (remember that stropping is sharpening) – but it must also leave the tool shiny (not dull) as this proves that the abrasive is a super fine ‘grit’.
When stropping, lay the tool flat on the leather and draw it backwards away from the edge. Use a fair bit of pressure, the finger tip turns a little white. This is needed because the compound is so super fine. (Do not flip the tool up and away at the very end of the stroke – this usuallly means an unconcious twist of the wrist – which will blunt the edge!) All knives flex slightly toward the tip – so one must slightly raise the handle as one nears the end of the stroke – to provide the same pressure to the last third of the tool as you do to the first third. If you have a tool whose edge is not holding up as well as you’d like after honing – try adding a microbevel to the edge by raising the back of the knife about the thickness of itself off the strop. This will put much more pressure on the edge. Be careful with this technique as too much pressure will round over the edge and make the tool cut poorly. What you are looking for is a compromise between too fragile an edge – and too rounded an edge. It is an important technique to learn and refine, think of it as adjusting the very edge of your tool microscopically. When a edge gets too rounded – that is what hones are for, a strop cannot re-flatten an edge.
Every so often I get an inquiry about strops that have become uneven / irregular / lumpy with the compound, normally occuring only after considerable service.
But the fix is easy!
Firstly, the hard wax that is the binder for the oxide polish is soften-able, so it may be softened by holding the strop – leather side down – over low heat till it is just warm to the touch. (hair dryer, cookstove etc.) don’t make it too hot to touch, just warm. This should make it easy to scrape off the old compound
Secondly, take a knife you’re not particular about, say an old butter or paring knife, and just scrape away, going sideways, to get back down to leather – holding the edge at 90 degrees /perpendicular to the strop surface.
In the future strive to apply the compound in even long strokes and use a bit less – properly used a strop should never get ‘lumpy’ – it means far too much compound is being applied.
Here’s one reply:
Thanks Del, I tried the process you suggested and found that heat provided a dramatic improvement over cold scraping (which I had tried but found it exacerbated the problem of lumpy surface, but I had been worried about melting the wax and damaging the leather), also during a run to the feed/hardware store I picked up a couple of plastic scrapers used for cleaning dishes/pots/pans or waters that felt sharp but removed the wax without damage to the nap of the leather. I used your suggestion of hair dryer and it was easy to control temperature to low heat. I am back to easy knife sharpening with excellent results. Thank you for your help! I believe carvers will find it a valuable addition to your website.
Again thanks for your help, Tom