rockstead maintenance with brasso

beschcode

beschcode

Joined
Nov 2, 2013
Messages
161
hi forum members.
i got two rockstead knives and it's time for some stropping. I've read in other posts that you can use Brasso metal polish for stropping instead of pikal. so i'm currently in mexico and found this brasso metal polish but i'm not sure it's the right one.

i would much appreciate if someone that have used this brasso before, would recommend it for rockstead kou zdp-189 and higo yxr-7.

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It tends to cut slowly even for a stropping compound. I'm thinking it'll barely work, if at all.
 
Rennd said:
It tends to cut slowly even for a stropping compound. I'm thinking it'll barely work, if at all.
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This. ^^

The abrasive in Brasso is silica-based, I'm pretty sure. As the name implies, it's intended for use on brass and other soft metals. On some very simple carbon steels at low hardness, it might work to a limited degree, because it may be just hard enough (barely). However, ZDP-189 is basically the opposite of that (not simple). Lots of chromium carbides in it, which are much, much harder than the silica abrasive in Brasso; not to mention, even the matrix steel (minus the carbides) is usually significantly harder than silica anyway. For stropping ZDP, I'd recommend, at a minimum, something like the aluminum oxide abrasives found in many 'white' stick-type buffing compounds, or in Simichrome or Flitz polishing compounds. Diamond and/or CBN (Cubic Boron Nitride) compounds would also work well, though they'll be more expensive. Nice to have, but not necessary.

(I tried some Brasso on a strop a few years ago, just to confirm my suspicions. I couldn't tell that it worked at all, on hardened knife steel.)


David
 
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You have two rocksteads and you want to strop them with brasso? Why not buy some proper strop compound in diamond or cBN?
 
Try Autosol. It's designed for stainless steel, I used it with some success, but I don't have zdp.

Edit to add: likely it won't work, but if you find brasso, you might find autosol.
 
fervens said:
You have two rocksteads and you want to strop them with brasso? Why not buy some proper strop compound in diamond or cBN?
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You're right I need to get proper compound and make denim strop. Which compound do u recommend and where can I buy it.?
 
Rockstead recommends pikal metal polish but I can't find where to buy it in small amount
 
beschcode said:
Rockstead recommends pikal metal polish but I can't find where to buy it in small amount
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The MSDS for Pikal liquid shows it's a 20% mix of Al[SUB]2[/SUB]O[SUB]3[/SUB] (aluminum oxide), along with mineral oil, kerosene and a balance of water. For a suitable equivalent, I'd just pick up some Simichrome or Flitz polishing paste; both use aluminum oxide abrasives, and both have proven successful for stropping as well. Looking at Rockstead's 'Maintenance' page (linked below; they're using the polish on a denim strop), their own commentary indicates the Pikal liquid is 'cheap', and similar products may be 'found in your own country' (or to that effect). In other words, there doesn't seem to be anything special or unique about it.

http://rockstead.jp/maintenance/

As previously mentioned, either diamond (such as DMT's Dia-Paste or Dia-Spray) or CBN would also work, and should remove any doubts about the quality of stropping, on these steels. I'd think it'd be relatively easy to find these, or the Flitz/Simichrome, from online sources like Amazon or whatever. Not sure which knife/sharpening specialty outlets actually ship to Mexico. Might check with BF member knifecenter.com for DMT products; looks like they carry Flitz as well.


David
 
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Chris "Anagarika";13355902 said:
David,

Al2O3 is actually white compound? If yes, then Autosol might work.
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Sometimes it's white; could also be grey, brown, blue, pink and maybe some other colors as well. And some 'white' compounds won't be Al2O3, but instead may be silica (think of toothpaste, and many rubbing compounds for use on car finishes) or tin oxide, which is very soft. Apparently, one version of tin oxide is actually referred to as 'white diamond', which is just a wee bit misleading, in terms of what it is and how it actually performs.

I tried looking up MSDS info on Autosol yesterday, but didn't see any specific mention of what type of abrasive it uses. I think I've seen some other posts or commentary here on the forums, indicating some success with it on knives. That might be a clue that it may have some AlOx in it, but hard to say for sure.


David
 
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David,

I use it all the time & works well with common steel (52100, 8Cr13MoV). Not so well with M4 (abrading matrix only, leaving the carbide free & toothy).

It must contain some harder elements, but not hard enough for Va carbides.

Now I am not sure if 52100 has lots of Chromium carbide, if yes, perhaps will work on ZDP too?
 
52100 has small amount of CrC (chromium carbide). zero VC.

ZDP189 has boat load of CrC, making it almost below stainless level 13%, thus stain & pit sometime. which mean more than 7% (from 20% composition) of Cr alloying up with carbon to form CrC. It also has small amt of WC & VC.

Chris "Anagarika";13360433 said:
David,

I use it all the time & works well with common steel (52100, 8Cr13MoV). Not so well with M4 (abrading matrix only, leaving the carbide free & toothy).

It must contain some harder elements, but not hard enough for Va carbides.

Now I am not sure if 52100 has lots of Chromium carbide, if yes, perhaps will work on ZDP too?
Click to expand...
 
Chris "Anagarika";13360433 said:
David,

I use it all the time & works well with common steel (52100, 8Cr13MoV). Not so well with M4 (abrading matrix only, leaving the carbide free & toothy).

It must contain some harder elements, but not hard enough for Va carbides.

Now I am not sure if 52100 has lots of Chromium carbide, if yes, perhaps will work on ZDP too?
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Bluntcut pretty much covered it. 52100 has a very minor amount of chromium (< 2%), and relatively typical carbon content around ~1%. Between the two, not much there to form significant chromium carbides at all. ZDP's HUGE abundance of chromium (20%; some oxidizes for 'stainless' qualities, the rest is what helps build carbides) and carbon (3%) will definitely add some wear-resistance. It reminds me of D2, in how it sharpens up; it also has high carbon + chromium. With quality AlOx, SiC or diamond, not a big deal (recommend diamond for setting bevels; just makes it quicker).


David
 
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White Conte crayons are supposedly almost 100% aluminum oxide, if you have an art store nearby. Pool cue chalk is silica dioxide, so maybe not hard enough. Wet/dry sandpaper maybe? Chrome polish is a safe bet.
 
HeavyHanded said:
White Conte crayons are supposedly almost 100% aluminum oxide, if you have an art store nearby. Pool cue chalk is silica dioxide, so maybe not hard enough. Wet/dry sandpaper maybe? Chrome polish is a safe bet.
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I'd forgotten there are some very good aluminum oxide lapping films out there too, great for stropping some of the higher-wear steels like D2 & ZDP. I've got some down to 0.3µ I believe; on the surface it simply looks & feels glassy, but it works very aggressively in polishing, immediately leaving dark swarf trails behind the blade on each pass.

I'd also forgotten about pool cue chalk. I'd tried it a while back (the blue stuff), just rubbing it on some clean paper and stropping a blade on it. The complete lack of swarf trails left on the paper suggested it's not likely hard enough for many modern steels, if actually attempting some honing with it. Might work on older or simpler steels at moderate-to-low hardness, or for burnishing or cleaning up burrs and other weakened remnants from the edge.

Going to have to look into the Conte crayons (hadn't heard of these); that sounds intriguing for some experimentation. A trip to Hobby Lobby might be in my near future. :)


David
 
beschcode said:
http://www2.knifecenter.com/item/DMTDPK/DMT-DPK-Dia-Paste-Diamond-Compound-Kit-of-1-3-and-6-Micron

I found this on knifecenter. should I use the 1 micron for my rocksteads on denim strop?
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You can, if you want to. But, DMT usually recommends using the diamond pastes on smooth leather or wood, like balsa or MDF. The paste will be harder to distribute smoothly and evenly on fabric (like denim) or on the 'nap' side of leather. Only way to get complete coverage on the denim strop would be to apply much more paste than is needed (expensive and wasteful), whereas a little bit goes a very long way on smoother surfaces. If buying the diamond paste, I'd reserve it for use on a smoother, firmer strop (examples: smooth leather, balsa, basswood, tight-grained hardwood like maple, or MDF).


David
 
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Try using tissue box cardboard (thin single layer) or those used for man's shirt backing when they sell it folded in the package, as a base. I used diwn to .5u with some success. Mixed the paste with some mineral oil to help spreading it.
 
Chris "Anagarika";13364637 said:
Try using tissue box cardboard (thin single layer) or those used for man's shirt backing when they sell it folded in the package, as a base. I used diwn to .5u with some success. Mixed the paste with some mineral oil to help spreading it.
Click to expand...

DMT has a video out now, in demo'ing their new 0.5µ Dia-Spray. Sort of surprised me, in that they included a similar piece of thin cardboard as one choice for substrates to be used with the spray. I've used the cardboard from Kleenex/tissue boxes or cracker boxes in a similar manner (over glass) with stick/crayon-type compounds, and it worked pretty well. Very good at burr cleanup, in particular.


David
 
As a cheaper solution than the diamond sprays, l bought myself a big tube of Flitz(metalpolish).
Applied it to a homemade jeans strop(as you can find on the rockstead homepage), let it dry!! Works like a charm, and is surely abbrasive enough to strop your knives with. Use it for my Zdp189 Hizen
 
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