How To Cleaning case CV blade?

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Apr 11, 2019
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102
Hi there,
So, I acquired an other CaseXX CV knife, a Sodbuster Jr., the other day with a fairly stained blade, not as bad as the first rusty Large Sodbuster I found, but there's a similar problem showing in both.

Both have a very small black spider webbing type thing going on that almost seems like it's deeper than a surface problem, but I don't know for sure, so I'm hoping someone with more knowledge and hands on with Case CV steel will be able to advise me.

The first one I cleaned by hand so just running out of elbow grease stopped me on that one at a point where it's ok.

Since then, I've made up some DIY buffing wheels for my Dremel out of Scotch-Brite pads ranging from 320 grit to 1200-1500 grit, and the 320 was very fast (3 or 4 minutes) in getting one side of the Jr. blade really close to the hours I spend on the Large Sodbuster however, that black spider webbing is showing up again, and it doesn't seem like the 320 grit is getting to it.

I don't want to keep at it and find out that I've gone too far.

First, a pic of the more obvious spider webbing in the Large Sodbuster.
Large_Sodbuster.jpg


Second, the Jr. before any cleaning.
P1060120.jpg


And third the current work in progress on the Jr. at 320 Grit.
Sodbuster_Jr_320_1.jpg


If I can get the Jr. really good I'll go back to the Large one.
I'm just being cautious.

Any thoughts?

Thanks!
 
That 'spider webbing' looks like some pitting in the steel from previous rusting/corrosion. Some 220-320 grit wet/dry sandpaper backed with something firm or hard, like wood, will work much more aggressively than the equivalent-grit-rated Scotch-Brite.

The small (Jr.) Sod Buster is likely a hollow grind blade; so, backing the sandpaper with a form matching that curvature should help as well. I think the large Soddie from Case is a flat grind blade. Putting the sandpaper flat on a hard surface, like glass, stone or the edge of a countertop, and then moving the blade over that will work fast in cleaning it up.

The whole key is using the abrasive (sandpaper) against a firm or hard backing. Really makes a big difference in working speed.
 
I actually enjoy the patina and light pitting, if the knife has one. I just get rid of any active rust and use them. Every time you sand our pits, you do loose material, and thin the blade. Sometimes that is not a bad thing. As many grinds have more material than they really need to be an efficient cutter.

Just go slow, and take your time, if you do sand.

I would probably just give them a light rub with either steel wool, or one of my loaded strops, and use away!!!
 
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That 'spider webbing' looks like some pitting in the steel from previous rusting/corrosion. Some 220-320 grit wet/dry sandpaper backed with something firm or hard, like wood, will work much more aggressively than the equivalent-grit-rated Scotch-Brite.

The small (Jr.) Sod Buster is likely a hollow grind blade; so, backing the sandpaper with a form matching that curvature should help as well. I think the large Soddie from Case is a flat grind blade. Putting the sandpaper flat on a hard surface, like glass, stone or the edge of a countertop, and then moving the blade over that will work fast in cleaning it up.

The whole key is using the abrasive (sandpaper) against a firm or hard backing. Really makes a big difference in working speed.

Yes. The Large is a flat grind and the Jr. is a hollow grind.
Matching the form of the hollow with a solid backing would be difficult, but your suggestion of sand paper tells me that it is able to be removed.
Thanks for the tips.
 
I actually enjoy the patina and light putting, if the knife has one. I just get rid of any active rust and use them. Every time you sand our pits, you do loose material, and thin the blade. Sometimes that is not a bad thing. As many grinds have more material than they really need to be an efficient cutter.

Just go slow, and take your time, if you do sand.

I would probably just give them a light rub with either steel wool, or one of my loaded strops, and use away!!!

Yea. I don't really hate the way it looks after the 320 Scotch-Brite and loosing too much material is my concern.
I think I'll just spend a bit more time with the 320 buffer and see what happens. If I don't get it all out then I'll just progress up in grits to get the scratches smaller.

I got into the Scotch-Brites needing to find a Steel Wool replacement because of it's metallic debris which loves to stick to magnetic things like guitar pickups.

Here's a pic of the DIY buffing wheels I made. Square when new is easier to cut (X-Acto knife and metal ruler) and square is not a problem as they round off after some use as shown by the green. After cutting 20 of those little squares the X-Acto blade was really dull and I got a chance to learn to sharpen an other type of blade.

Maroon = 320
Green = 600
Light Grey = 800 (**** Steel Wool equivalent)
Blue = 1000 (melts easily when used at high speed)
White = 1200-1500

DIY_Buffing_Wheels.jpg
 
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Yea. I don't really hate the way it looks after the 320 Scotch-Brite and loosing too much material is my concern.
I think I'll just sped a bit more time with the 320 buffer and see what happens. If I don't get it all out then I'll just progress up in grits to get the scratches smaller.

I got into the Scotch-Brites needing to find a Steel Wool replacement because of it's metallic debris which loves to stick to magnetic things like guitar pickups.

Here's a pic of the DIY buffing wheels I made. Square when new is easier to cut (X-Acto knife and metal ruler) and square is not a problem as they round off after some use as shown by the green. After cutting 20 of those little squares the X-Acto blade was really dull and I got a chance to learn to sharpen an other type of blade.

Maroon = 320
Green = 600
Light Grey = 800 (**** Steel Wool equivalent)
Blue = 1000
White = 1200-1500

DIY_Buffing_Wheels.jpg
Didn't realize there are so many scotch brite varieties, your a newbie and already contributing good job brother
 
You're welcome.
I've put 2 files in a folder on my site that might be useful.

http://www.sightsea.com/renders/3M_Scotch-Brite/

They are:
1) the Official 3M .pdf on the grit/color which also shows the official 3M number for each grit which can make it a lot easier to find them on the web.
2) Some info in a .txt from an other site which seems a more accurate evaluation of the grits relative to wood working.
 
Yes. The Large is a flat grind and the Jr. is a hollow grind.
Matching the form of the hollow with a solid backing would be difficult, but your suggestion of sand paper tells me that it is able to be removed.
Thanks for the tips.

For sanding in the hollow grind, you could also just radius one edge of a wooden block to round it off a bit, then wrap the sandpaper around that rounded edge. Make linear sanding passes between the spine and the edge, to keep the sanding pattern uniform.

OR, you could also wrap the paper around a piece of fairly large-diameter wooden dowel or PVC pipe and make linear passes from heel to tip. This might actually be easier than going spine-to-edge with a wooden block as described above.
 
Warning on the Blue Scotch-Brite!

I started going up in grits and when I got to the blue pad it deposited the blue dye from the pad onto the blade.
Also, it wasn't easy to get back off. I had to go back down to 320 grit to get rid of the blue stain.

The Green and the Blue are the consumer "get 'em anywhere" all purpose cleaning pads so maybe quality control isn't as good.
So, I'm not going to use the blue pads for anything that I care about.

However, I had no problems at all with the Green.
 
No, you melted the plastic the pad is made from onto your blade.

OK, but even so, that hasn't happened with any of the other grits / colors which have had much more use at this point and much more speed and pressure.
That blue came of at the lowest speed possible on my Dremel and with minimal pressure.
I also tested it on an other piece of metal that isn't knife blade and got blue melted stain right off the bat,
so there seems to be something different with the blue pads.
Maybe they really are meant for light duty cleaning only.
 
Blue Scotch-Brite is rated pretty fine, like 1000 grit or so. Fine enough, they describe the material as 'non-scratch' (which basically means it's not very abrasive). The risk of it overheating is greater, due to that. It won't remove metal as fast, and will also clog very fast. Both of those factors will make it generate more friction-related heat, especially if used on a driven tool like a Dremel. These 'cleaning pads' are designed to be used by hand for cleaning stuff not nearly as hard as steel; used as such, they ordinarily shouldn't generate enough heat to be a problem.

A similar effect happens if using something like a cotton buff wheel with green compound to polish plastic knife handles. The fineness of the green compound (usually less than 1 micron) means it can't remove material fast enough at driven, powertool speeds, and it generates enough friction-caused heat to melt plastic handle materials like Delrin, if the driven buff wheel lingers more than a second or two in one spot. Happens very fast.
 
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OK, but even so, that hasn't happened with any of the other grits / colors which have had much more use at this point and much more speed and pressure.
That blue came of at the lowest speed possible on my Dremel and with minimal pressure.
I also tested it on an other piece of metal that isn't knife blade and got blue melted stain right off the bat,
so there seems to be something different with the blue pads.
Maybe they really are meant for light duty cleaning only.

The problem is that you are using abrasive pads meant to be used in the hand and putting them into a powered grinder. You are using them outside their intended application, for which they were not designed. You can't blame the manufacturer for that one. The other varieties may just perchance be able to handle the heat, while the blue one can't.

Edit: somehow missed OWE's post until after posting mine. He nailed it.
 
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