Strop Saturation

[bp122]

Hi all

When I started woodworking a few months ago, after sharpening my chisels and plane irons, I used to strop them to a high shine - which helped a lot.

But now, I don't seem to get the same shine with the same method on the same chisels / plane irons on the same strop (piece of leather from workshop heaven on a flat melamine faced chipboard 1.5" thick with green compound) The finish appears very dull and kinda cloudy.

I thought a superfine polishing paste paste from Axi might make a difference - still no joy and no better finish than I got with the green compound.

I was wondering if this is because the strop is saturated and smoothed out so much that it cannot give the shine it once did?
Or is it the cold temperature in the winter that perhaps doesn't let the polishing compound work its magic fully?

Thoughts?

 

[Cheshirechappie]

If your chisels and plane irons are cutting wood as well as they did before, then don't worry about it - the strop is still doing it's job. After all, it's the sharpness of the edge that counts rather than the polish on the bevel.

 

[Trafalgar]

The waxy, green sticks are designed for power buffing. The act of buffing creates heat, the wax melts, and the grit is then exposed to the steel being polished. Once the buffer is turned off, the wax cools and solidifies for the next session where the phenomenon repeats itself.

Forget the green sticks. You should lightly charge your strop with a dry compound followed by a very little mineral oil. Do not using a vegetable oil of any kind as they oxidize and form a sticky sludge. Or, don't charge the strop at all.

You can buy vials of dry polishing products through companies that supply them to the optics industry. If they're good enough to polish glass lenses worth thousands of dollars, they're good enough for tool steel. One vial will last the rest of your working life, as will one small bottle of mineral oil.

 

[bp122]

If your chisels and plane irons are cutting wood as well as they did before, then don't worry about it - the strop is still doing it's job. After all, it's the sharpness of the edge that counts rather than the polish on the bevel.

My chisels (set of old marples) don't hold their edge for as long as they did, or at least that is what I feel - especially when paring down to a knife wall on hand cut joints. That is why I wondered if it had anything to do with the stropping.

The waxy, green sticks are designed for power buffing. The act of buffing creates heat, the wax melts, and the grit is then exposed to the steel being polished. Once the buffer is turned off, the wax cools and solidifies for the next session where the phenomenon repeats itself.

Forget the green sticks. You should lightly charge your strop with a dry compound followed by a very little mineral oil. Do not using a vegetable oil of any kind as they oxidize and form a sticky sludge. Or, don't charge the strop at all.

You can buy vials of dry polishing products through companies that supply them to the optics industry. If they're good enough to polish glass lenses worth thousands of dollars, they're good enough for tool steel. One vial will last the rest of your working life, as will one small bottle of mineral oil.

What you have written makes sense. However, I also tried the same compund with light passes on the strop and with heavy quick passes - it seems the heavier the pass, the less shine there is - which didn't make any sense to me as I too thought the frictional heat would help. Just for laugh, I also tried the green compound on some cheap polishing mop on a drill press - even that didn't give me a good shine - But these mops aren't good quality and very flimsy and weak - maybe that is why.

 

[D_W]

Worrying about the polish level isn't really the right object (the tool). Look at what it does and how it feels through the cut.

Strops get loaded over time with all kinds of stuff - contaminants that settle on them, abrasives from prior steps, wire edge particles that come off in the leather, etc. Take a card scraper and scrape the surface of your strop off to get to clean bare leather (use the opposite side that you have a burr rolled on, that's fine). nothing drastic, just scrape off the layer of used abrasive, contaminants, wax, oils, etc.

I've sold razors in the past and looked at a lot of thing under a microscope (because that's the only ethical way to separate and grade items sold for razors). The evenness of an edge is not a lot different under some of the wax sticks (the green one you mention) and very uniform graded abrasives, but the appearance of scratches is a little bit different (away from the bevel).

If you're going to use the green sticks, add a couple of drops of non-drying oil when you apply them and scrape your strop once in a great while to make sure it's free of contaminants. But that's sort of the same thing as cleaning paint brushes - you just do it as a matter of keeping the tool in decent shape, a clean brush that does an equivalent job but has a little bit of paint way up at the ferrule isn't that big of a deal. You can get in a situation getting fascinated over polish where you drive yourself bonkers about every little light scratch - and the better the polish, the easier they show, even though they'll not show up on work.

Charlie mentions not using vegetable oils. That's good policy. If that's all you have, go ahead and use them, anyway - you can scrape off anything that dries. Still better policy to use mineral oil if you can find it affordably (unscented baby oil, commercial kitchen supply, veterinary supply, etc). Any question about contamination, etc (especially if something notches an edge), scrape the strop again. Be sparing with the compound when you apply it, no matter the type.

 

[Trafalgar]

I'd start over with a new strop, or even two, one treated as I mentioned and one untreated. If you don't want to source the optic polishing compounds then the very finest diamond paste you can find will work too. If using the latter you won't need the mineral oil. I use a hard rubber strop with AlOx powder FWIW. It does what a strop is supposed to do - removes rag, secondly imparts polish. I don't take lots of strokes. Sharp is a geometric concept, not necessarily a function of high shine, but if you can impart polish without destroying the geometry then so much the better. In any case, less is more. It's like taking an aspirin a day to prevent a heart attack. One is good. Four is bad.

And, if you like, you can do a slight lift for a few strokes and hit the back right at the cutting edge and achieve the same effects of the 'ruler trick' without the risk of putting in a back bevel. And, unlike the ruler trick, you can do this on chisels. The next time you hone, you'll see the tiny sliver of polished steel honed away which is exactly what you want. You want to put in the extremely narrow sliver of polished steel afresh, after each honing. You can of course use the strop as a touch up by itself, but I would alternate between the treated and untreated leather in doing so. If you ever get to the point that the highly polished edge is not being honed away almost instantly, you're probably spending too much time on the strop as a touch up. This may not apply to your carving chisels -- it depends on what shapes you're working and what woods you work in.

 

[ED65]

Or is it the cold temperature in the winter that perhaps doesn't let the polishing compound work its magic fully?

That could well be a factor. Since you did the smart thing and tried it on a mop it does seem a possibility; I was going to ask if you had changed your stropping technique without realising it but this seems to discount that as a possible explanation.

As you mention that the strop is saturated I think that's going to be part of it. With the green wax-based sticks (whether they are CrO or a mix or just faux) just a scribble seems about the right amount.

I've experienced the same thing and I took it as a sign that the strop needed more compound or fresh compound, and topping up confirmed this. But I'm using metal polish which is very different.

 

[bp122]

Worrying about the polish level isn't really the right object (the tool). Look at what it does and how it feels through the cut.

Strops get loaded over time with all kinds of stuff - contaminants that settle on them, abrasives from prior steps, wire edge particles that come off in the leather, etc. Take a card scraper and scrape the surface of your strop off to get to clean bare leather (use the opposite side that you have a burr rolled on, that's fine). nothing drastic, just scrape off the layer of used abrasive, contaminants, wax, oils, etc.

I've sold razors in the past and looked at a lot of thing under a microscope (because that's the only ethical way to separate and grade items sold for razors). The evenness of an edge is not a lot different under some of the wax sticks (the green one you mention) and very uniform graded abrasives, but the appearance of scratches is a little bit different (away from the bevel).

If you're going to use the green sticks, add a couple of drops of non-drying oil when you apply them and scrape your strop once in a great while to make sure it's free of contaminants. But that's sort of the same thing as cleaning paint brushes - you just do it as a matter of keeping the tool in decent shape, a clean brush that does an equivalent job but has a little bit of paint way up at the ferrule isn't that big of a deal. You can get in a situation getting fascinated over polish where you drive yourself bonkers about every little light scratch - and the better the polish, the easier they show, even though they'll not show up on work.

Charlie mentions not using vegetable oils. That's good policy. If that's all you have, go ahead and use them, anyway - you can scrape off anything that dries. Still better policy to use mineral oil if you can find it affordably (unscented baby oil, commercial kitchen supply, veterinary supply, etc). Any question about contamination, etc (especially if something notches an edge), scrape the strop again. Be sparing with the compound when you apply it, no matter the type.

Thanks, D_W. I don't have a card scraper, but I do have a good scraper for scraping paint imperfections. I will try that.

Regarding oil, I have some 3-in-1 oil. I also have some wax from Axi if needed instead of petroleum jelly.

I'd start over with a new strop, or even two, one treated as I mentioned and one untreated. If you don't want to source the optic polishing compounds then the very finest diamond paste you can find will work too. If using the latter you won't need the mineral oil. I use a hard rubber strop with AlOx powder FWIW. It does what a strop is supposed to do - removes rag, secondly imparts polish. I don't take lots of strokes. Sharp is a geometric concept, not necessarily a function of high shine, but if you can impart polish without destroying the geometry then so much the better. In any case, less is more. It's like taking an aspirin a day to prevent a heart attack. One is good. Four is bad.

And, if you like, you can do a slight lift for a few strokes and hit the back right at the cutting edge and achieve the same effects of the 'ruler trick' without the risk of putting in a back bevel. And, unlike the ruler trick, you can do this on chisels. The next time you hone, you'll see the tiny sliver of polished steel honed away which is exactly what you want. You want to put in the extremely narrow sliver of polished steel afresh, after each honing. You can of course use the strop as a touch up by itself, but I would alternate between the treated and untreated leather in doing so. If you ever get to the point that the highly polished edge is not being honed away almost instantly, you're probably spending too much time on the strop as a touch up. This may not apply to your carving chisels -- it depends on what shapes you're working and what woods you work in.

Thanks, CStanford.
I'll start over with two new strops - may not be leather as this ist he last strip I have. I have endless supply of old denims and mdf pieces.

 

[bp122]

Or is it the cold temperature in the winter that perhaps doesn't let the polishing compound work its magic fully?

That could well be a factor. Since you did the smart thing and tried it on a mop it does seem a possibility; I was going to ask if you had changed your stropping technique without realising it but this seems to discount that as a possible explanation.

Didn't have a technique worthy of giving a name or notice a change in to begin with :mrgreen: (homer) (homer) (homer)

 

[D_W]

Wipe the chisel on something clean (not the strop) at some point, too, and make sure that the haze you're seeing isn't just a mix of oil/oxidized stuff/wax.

I have two strops that I've used for years now. One is cow, one is butt strip (horse). Both have been loaded with something or not at one point or another, and neither suffers any ill effects from being scraped (and neither had ever come loose from the wood substrate, despite fairly generous use of oil from time to time to make the scrape clean). They do have a few marks on them, but nothing that affects their use. Even razor strops get dirty with metal over time and need surface cleaning and oiling (and they are babied - but too expensive to just swap out when they get dirty). It's not the same kind of dirty, though - just discoloration.

As charlie says - if doctoring it doesn't solve things, just get another strop. Veg-tanned cow and horse butt strip (smooth if possible, not with wrinkles) both make excellent strops, and leather like that kept in a dry place is something you'll find uses for (lining vise jaws, use on fixtures, etc). Just like mineral oil and beeswax.

 

[--Tom--]

As above, scrape it to freshen up the surface and then reapply compound of choice.

I’d avoid oiling the strop as it’s easy to add to much and that impacts the results much more than not oiling.

 

[MikeG.]

Try it with Brasso/ T-Cut. The idea of a strop is to take stuff off the steel, not add stuff on to it, so the wax thing has never seemed like a great idea to me.

 

[D_W]

Wax is probably not ideal, but if it's what's available, using it sparingly is fine - a drop of oil with it and a light touch - just a few strokes- makes for easy and suitable application. There have been some displays on the forums of strop surfaces encased in wax, though, and the call for LV's demise because of the ineffective results (the ineffective party was the user).

Until someone got an MSDS, razor users were pretty happy with the formax microfine compound - razors being far more sensitive to application led to drawing a few X's on a strop and that's it.

The solution to finding out that something that worked fine in practice was not suitable on paper was to spend more on fine graded powder. Spilling green pigment may make someone wish for the wax crayon, though.

I've tried just about everything for gits and shiggles and can't say I've got a suitable preference for one thing over the next as long as the product isn't outright junk (powder or stick, diamond or oxides, etc).

 

[bp122]

Thanks all

I will try and rejuvenate the strop surface this weekend (away for work until Friday!) and also make two new strops on the side (one with and one without compound) to compare which one works best!

Thanks again for everyone's input.

 

[ED65]

If you're up for making a couple of new strops I highly recommend you try two new types.

First is just plain MDF, just the factory surface. So this one should take you all of a minute :mrgreen:

Second is a faced strop but not using leather. The substrate can be anything really but use denim for the surface; I think you'll be mightily surprised at how well it works compared to leather, and the price is right!

 

[bp122]

If you're up for making a couple of new strops I highly recommend you try two new types.

First is just plain MDF, just the factory surface. So this one should take you all of a minute :mrgreen:

Second is a faced strop but not using leather. The substrate can be anything really but use denim for the surface; I think you'll be mightily surprised at how well it works compared to leather, and the price is right!

It is like you read my mind! I was going to do exactly the same thing. All with MDF, one bare, two with Denim (one with each of the two compounds I have). I have been saving a lot of old clothes to use as rags etc. There are a couple of denims there. Should it be double layered or something or just a simple single layer stuck using PVA will do?

 

[MikeG.]

I used to use MDF, but found that once it got nicked by clumsily waving around a razor sharp edge it needed some attention, whereas leather self-repairs just by smoothing over with the blade you happen to have in your hand.

 

[ED65]

Should it be double layered or something or just a simple single layer stuck using PVA will do?

Just a single layer is what I used and it held up well. I didn't skimp on PVA and really clamped down hard using a clamping block for even pressure across the whole surface. It ends up a very firm surface without the give that one might expect.

This first one has lasted me about five years and I expect the next one to last far longer since A, I strop much less now than I used to (don't always finish by stropping and use fewer strokes when I do) and B, tend to strop more slowly than I did. I started by following Paul Sellers's method and have gradually migrated away from it as I came to realise you can get the same effect from fewer strokes taken more slowly/deliberately, and with much less chance of dubbing an edge.

Loaded the way I have it denim too can somewhat self-repair if you get a minor catch, and you can successfully glue down some more major catches but there's a limit obviously. I got a bad catch sometime last year that caused a ruck that wouldn't go away so I'm actually overdue for replacing the denim... but as you can tell from this being months ago a strop is still usable with a minor lump on it