Paper micarta grinding and finishing

H

Hubert S.

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Dec 14, 2019
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I made a knife handle from paper micarta yesterday, first time working with this material. It is the cross cut mocha paper micarta from Pop's. The picture does not quite do it justice, it has a lot more depth than I was able to capture with my phone's camera.

I swear this stuff burns before you even turn on the grinder! I had no luck with a pretty new 36 grit ceramic, it would clog and then burn the handle very quickly. I ended up using aluminum oxide J-flex belts up to 240 and that worked well enough. I frequently cleaned the belts with an eraser and compressed air. Since I did not have anything higher grit in J-flex AO, I went to Trizact belts and immediately got a burn mark. Maybe I ran it too fast or with too much pressure? I went back to the AO belts to get the burn mark out and then sopping wet cork followed by a super fine Scotchbrite belt. I like the finish, but I am wondering if there is a better way. I have three more blades ready for handles that I want to use this material on, so I am wondering what y'all recommend for heavy material removal and for finishing paper micarta. Do you put a finish like wax or oil on it or not?

Also, does anybody know if micarta has a tendency to shrink and expand like wood, or is it pretty stable? I am contemplating a handle with dowel construction using a metal spacer, maybe copper.

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Beautiful knife! I tend to run my belts no higher than 30% on my VFD when working with micarta. Depending on grit I adjust speed up or down, as well as time on belt.

For finishing I come off the belt at either 220 or 400, hand sand to 800, then do a light machine buff and it shines like glass. Just one way out of I’m sure a million
 
I only use open grit abrasives on Micarta, good old brown AO. Coated abrasives like ceramics will clog and burn faster, they are not made for grinding this stuff.
I rough shape with P60 on a contact wheel. Then P80-180-400 on slack platen. I make contoured western style handles. Then hand sand 400-1000 (1500) and buff.
 
I had it in white as S Scaniaman said, use belts for wood not metal. I use brand new 36 grit and a belt eraser.

Then I gently moved to 50 grit and hand sanded from there.
 
Do you have any specific belt recommendations? The belts I used were blue Hermes J-flex aluminum oxide (RB406JF), not sure if that is an "open abrasive", it does not say either way on the trugrit site. I see some brown Hermes (RB346MX) and Klingspor (CS310X) belts, would those be better suited for this? The coarsest AO belt I had was 80 grit and it took quite a while to shape the handle without burning it, but it worked a lot better than the 36 grit ceramic.

I have made a test piece with a 240 grit finish and will hand sand that to 800 grit to see if that's worth the effort.
 
one or the other, burning means too much pressure, too fast of a belt speed, or too dull of a belt. what brand of 36 grit are you using that is clogging? i have not encounterd that except on higher grits. if its hot enough to discolor it, its probably melting somewhat making it more likely to stick to the belt and clog. i would try a slower speed.
 
the 80 should not work better than the 36. they must be different brands. all ceramics are not alike.
try a brand new 3m cubitron 984f 36 grit and get back to me. i dont recall burning anything shaping deep handle curves with a sharp one. i find shaping anything with 80 is likely to burn it, and for sure with 120 grit. snakewood loves to burn, and burn deep. my 80 is only to remove the 36 grit scratches, and the 120 is only to remove the 80 grit scratches. either you save $ by going real slow with less efficient belts and frustration, or get it done in 5 minutes with a nice zippy new 3m. i always try to use my belts on handle material first, then steel later. you can go so much faster with no BS. its actually more cost efficient. i also keep a set of belts just for leather sheath shaping and smoothing. 36 to 400. i use a 984 f there as well, the same 36 is still pretty sharp after 2 years. soon i will replace it with a fresh one, and use the old one on metal. the same thing happens with burning on the sheath edges too.
 
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john april said:
the 80 should not work better than the 36. they must be different brands. all ceramics are not alike.
try a brand new 3m cubitron 984f 36 grit and get back to me. i dont recall burning anything shaping deep handle curves with a sharp one. i find shaping anything with 80 is likely to burn it, and for sure with 120 grit. snakewood loves to burn, and burn deep. my 80 is only to remove the 36 grit scratches, and the 120 is only to remove the 80 grit scratches. either you save $ by going real slow with less efficient belts and frustration, or get it done in 5 minutes with a nice zippy new 3m. i always try to use my belts on handle material first, then steel later. you can go so much faster with no BS. its actually more cost efficient. i also keep a set of belts just for leather sheath shaping and smoothing. 36 to 400. i use a 984 f there as well, the same 36 is still pretty sharp after 2 years. soon i will replace it with a fresh one, and use the old one on metal. the same thing happens with burning on the sheath edges too.
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I think I probably ran the 36 grit too fast, it was an almost new VSM ceramic and the micarta probably melted a bit. The belt had some residue on it that would not come off with the eraser... This belt had only been used to shape one wooden handle before, so I figured it's not the right thing for paper micarta. Plus, I had read some old forum posts where people reported having better luck with AO, so I switched to the coarsest AO I had. I have to order more belts soon anyway and will give the Cubitron a try.
 
I really like Klingspor AO. LS307 and LS309. LS312 I use also because it is readily available with scallop edge.
 
LS307 has an X weight backing and is excellent for heavy removal in 60 grit. The others are J weight.
 
1 X 30 grinders aren't exactly fast.
You can rough shape the handle by grinding, then file it to final shape, then hand sand.
 
razor-edge-knives said:
I just use a sharp low grit belt to shape then progress up to 2k grit + buff

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Jarrett Fleming said:
I can rough shape a lot of handles (dozens) with a 50 grit ceramic blaze. After rough shaping I finish on the grinder with a 220 jflex. I use the yellow klingspor w/ blue back. Then I swap to hand sanding. This one was taken to 2k then lightly buffed.
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Nice knives and handles. I must have been doing something wrong, probably too fast and/or too much pressure. I am hoping to make another one this weekend and have not gotten any new belts yet, so I'll try the ceramic again and go slower.
 
I was definitely doing it wrong on my first try, too fast and too much pressure. I slowed down the grinder to a bit under 50% and avoided the burning, but it took quite a while to remove the material. The ceramic belt still requires frequent cleaning so I'll check out the open grit belts and see if that works any better. The picture shows the handle I made today for a honesuki. It has a spacer I made from a piece of 1/2" copper pipe.

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