My take on the LV chromium oxide compound

[Patrick Chase]

I'm splitting this off from the "Spyderco" thread as it's a tangent, but want to make a couple remarks in the wake of the recent "rediscovery" that the LV honing compound contains larger Al-Oxide particles.

As noted in the other thread, the LV honing compound is very cheap as abrasives go, at $0.07/g. That puts it at about 1/100th of the cost of quality diamond pastes, and 1/7th that of the pure Cr-Oxide paste that Stewie cited. The thing to bear in mind is that that price point doesn't really support expensive processing or process controls.

As also noted in the other thread, the real-world performance of the compound in question is MUCH better than implied by the "300- grit" specification that its ultimate manufacturer provides.

What I think is happening is that the grinding process for the Al-Oxide in that paste actually produces very small particles the vast majority (and perhaps even all) of the time. Because of the price/cost constraints they're unable to do anything fancier than sieving to grade the resulting particles, and as a result the finest grit they can specify is the size of their sieve, hence "300-". In my experience as a (former) mechanical engineer this sort of thing is very common in cost-constrained products. While you may achieve some level of quality the vast majority of the time, you can't afford the incremental cost to do what it takes to formally claim that as your specification.

What I'm driving at here is that I wouldn't read too much into that spec. As I've said many times, based on my own experience I don't think the stuff is really "0.5 um", but it definitely isn't "300 grit" either. If it's working for you then stick with it. If you haven't tried it and you're on a budget then you probably should at least give it a go, because IMO it's good enough for (most) woodworking and the value is unbeatable.

You can get finer edges with a good polishing stone or tightly-graded compound, but I'm still not convinced that matters for anything but planing competitions and bragging rights. Full disclosure: I'm obsessive enough that I use tightly graded films and pastes much of the time. I'm just trying to be realistic about what all of that buys me (mostly speed IMO).

[Patrick Chase]

First, I doubt that he was stropping with the LV compound. Most of the competition and straight-razor folks seem to go for either untreated strops or more exotic compounds like 0.025 um CBN sprays. Given Brian's known burr-detecting abilities (his apprentice recently compared him to the Princess and the Pea) I suspect that he was using an untreated strop to do final burr remover after his JNat polishers. I therefore doubt that whatever he saw has relevance to this discussion.

Second, nobody I know takes or needs to take continuous and flawless 8 micron shavings that must run the entire length of a cherry-picked piece of clear/straight-grained timber as part of their daily woodworking. For that specific use I can easily believe that stropping would be counterproductive on multiple levels, starting with the fact that you fundamentally give up some control of tip geometry when you strop with compliant media. I don't think anybody (even Brian) would generalize from "you need to do X to win planing competitions" to "you need to do X to make good furniture". That was really the point of the remark you quoted.

[Patrick Chase]

Patrick; I recently asked you, what was your logic in owning a #7, # 7 1/2, and #8 jointing planes. You answered my question by stating, "who said there was any logic applied."


and now we have this statement.

Since you asked, I bought the BUJointer ("7-1/2") first when I thought that BU was the way to go because it provided easier edge-angle control. Then along came the latest rediscovery of cap irons, as well as the Veritas custom planes which made angle changes easy by offering modular frogs. That's when/why I got the 7. Then I tried an 8 and decided I really liked the extra size for panel work. If I had it to do again I'd skip the 7-1/2. I think "who said there was any logic applied" conveys the amount of thrash and evolving knowledge involved much more concisely and efficiently, though.

[Stewie Simpson]

I had a look at the feasibility of using the higher cost premium diamond pastes. The research I carried out suggests that dependant on the substrate used within the strop, what can occur is that the hard diamond particles will embed themselves within the substrate to the point they make no actual contact with the cutting edge being honed. I am hopeful the particles within the pure chromium oxide will not be offer a different outcome. On the subject of the Chromium Oxide Jewellers Rouge, it should be remembered that the wax component within these products deems it better suited for high speed power stropping, where the friction heat generated will soften the wax to expose the polishing compounds within. That its being advertised for use with hand stropping I am yet to fully understand.

Stewie;

[Kees Heiden]

About the subject, I use Autosol, because the LV green compound isn't easilly avialable overhere. Autosol is also cheap, I have no idea how it is rated but it puts a nice shine on my bevels

[Pat Barry]

... The research I carried out suggests that dependant on the substrate used within the strop, what can occur is that the hard diamond particles will embed themselves within the substrate to the point they make no actual contact with the cutting edge being honed. I am hopeful the particles within the pure chromium oxide will not be offer a different outcome. Stewie;

The largest particles are typically going to be odd shaped and longer than they are wide, for example. As such they are not stable standing straight up where you might think that they would be prone to putting a deep gouge into your edge. The most likely scenario is that the larger particles just lay down on the surface due to simple physics as part of the honing process . I suppose that they all must embed to a point (sic) just so that they don't slide all over. I think it highly unlikely that the large particles get driven very deeply into the strop surface however. As for not making contact, unless all the particles are exactly the same size and shape, the smalletst one will not make contact, again due to simple physics.

[Stewie Simpson]

Kees; David Weaver mentioned recently he has had success using a different stropping compound, I cant remember what that product was, Derek may recall.

Stewie;

[Stewie Simpson]

The largest particles are typically going to be odd shaped and longer than they are wide, for example. As such they are not stable standing straight up where you might think that they would be prone to putting a deep gouge into your edge. The most likely scenario is that the larger particles just lay down on the surface due to simple physics as part of the honing process . I suppose that they all must embed to a point (sic) just so that they don't slide all over. I think it highly unlikely that the large particles get driven very deeply into the strop surface however. As for not making contact, unless all the particles are exactly the same size and shape, the smalletst one will not make contact, again due to simple physics.

Hi Pat; some of the diamond pastes and honing sprays available on the market are down to 0.5, 1, and 2.5 micron in sizing. http://www.bestsharpeningstones.com/...mond-Spray.htm

Stewie;

[Stewie Simpson]

Kees; you may find the following study of interest. https://scienceofsharp.wordpress.com...-strop-part-3/

Stewie;

[Derek Cohen]

Stewie, did you read the home page, where the author writes ..

There is a misconception that more expensive, higher purity abrasives with tighter size distributions are always superior.

Regards from Perth

Derek

[Stewie Simpson]

As a user of natural water stones, I found the following study on Jnat slurry of great interest.

https://scienceofsharp.wordpress.com...slurry-part-2/

Stewie;

[Brian Holcombe]

I haven't taken any offense to this thread, so no worries there.

WRT to the relevance of the planing competition to regular work, it's a few measures of extreme beyond what most would normally take but it helps the participants in problem solving when they return to normal work. I prepped the beam with winding sticks followed by a 3' precision straight edge and a 1 thou feeler gauge, not a lot of people had seen that sort of thing done and it was maybe an 'ah-ha' moment to witnesses who have trouble taking a full length shaving. Normally one does not need that extreme but when you see it, it helps problem solve if you are not getting full shavings (and blaming your plane).

Same can be said about the extreme degree of sharpening or sole prep or anything of that sort. It helps you determine what is actually critical in normal use and to separate what truly matters from what makes little difference and even further to what is actually causing you a disservice when you thought otherwise.

Basically if you have figure out how to take an 8 micron or thinner shaving it causes you to become very good at taking 100 micron shavings.

[Bruce Page]

Folks, I have done a lot of editing/deleting in an attempt to get this thread back on track and to remove several personal attacks.
Please stay on topic.

[Patrick Chase]

Stewie, did you read the home page, where the author writes ..

"There is a misconception that more expensive, higher purity abrasives with tighter size distributions are always superior."

Regards from Perth

Derek

Indeed, particularly when one considers cost-effectiveness.

What I think the tightly-graded abrasives do ultimately buy you is speed. I say "ultimately" because it's indirect. IMO edge quality is largely determined by the larger particles in the abrasive medium.
It doesn't matter if 95% of the edge is pristine if the other 5% has massive scratches. This means that if you have a loosely-graded abrasive you have to "de-rate" a bit more to achieve any given quality.

Conversely, speed is mostly determined by the nominal particle size. Returning to my example above, the overall speed at which metal is removed is governed more by the 95% of the edge that's getting polished.

What this means in the real world is that a tightly-graded abrasive lets you use a higher nominal size for any given target quality, and that translates to higher speed. You'll pay dearly for that speed, though, so whether it's "superior" or not depends a lot on what value you assign to your time.

[Patrick Chase]

I had a look at the feasibility of using the higher cost premium diamond pastes. The research I carried out suggests that dependant on the substrate used within the strop, what can occur is that the hard diamond particles will embed themselves within the substrate to the point they make no actual contact with the cutting edge being honed.

Very true. I've seen the same thing even with MDF, never mind leather. FWIW I use mild steel and cast iron plates, but you can't really call it "stropping" at that point. It also takes a while to get your fine-grit plates flattened to the point where they cut efficiently in succession, particularly for wider tools.

I am hopeful the particles within the pure chromium oxide will not be offer a different outcome.

Both Cr-oxide and diamond are effectively "infinitely hard and sharp" compared to leather or MDF, so I wouldn't expect a different outcome. IMO the biggest difference is that at 1/100th to 1/10th the price of good diamond compound (for LV and the pure Cr-oxide you bought, respectively) it isn't a big deal if you have to periodically refresh it.

w.r.t. the wax thing, a lot of people work in some mineral oil when they apply the compound. At that point the wax in the bar is just a convenient storage/delivery vehicle, which the user "seasons to taste".