looking for glass or granite for sandpaper

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parttimevegan

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I want to do some very course flattening on the side of a very thick cleaver. I need it to be super flat at every stage of shaping and polishing. I have a shapton extra course stone but the stone is taking a lot of damage and the cutting action with water is too slow. I am looking into getting a glass plate but they are sold out where I shop. what do you think of granite? maybe I can polish the granite to get it flatter? what do you use to attach the sandpaper to the glass. I have seen videos of people using a weak spray adhesive.

 

M1k3

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Take one of those wood hand sanders with a handle and mount it upside down in a vice? Credit to @stringer
 

heliosphere

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I want to do some very course flattening on the side of a very thick cleaver. I need it to be super flat at every stage of shaping and polishing. I have a shapton extra course stone but the stone is taking a lot of damage and the cutting action with water is too slow. I am looking into getting a glass plate but they are sold out where I shop. what do you think of granite? maybe I can polish the granite to get it flatter? what do you use to attach the sandpaper to the glass. I have seen videos of people using a weak spray adhesive.
A granite surface plate will be very, very flat, and anything you do to it will only make it less flat. The one you linked to claims to be flat to with .0001 inch, which is .0025 mm. They are also very heavy, so shipping may be expensive. If there's a Woodcraft store near you, you can pick one up there. It will cost more, but you won't have to get it shipped.

I don't know a ton about the flatness required for thinning knives, but I think that a granite surface plate is probably way flatter than you need. You can get granite tiles from a home center -- but make sure to check for flatness, because they might not be flat enough.

For sandpaper, I would skip spray adhesive. In my experience, the overspray goes places you don't want it to go and it's a pain to clean it up. Instead, you can get rolls of sandpaper that has an adhesive back. Search for "PSA sandpaper."
 

Desert Rat

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I use scrap granite from a sink cut out. It's flat and it was free. Overkill at 1 1/4" thick but functional.
 

Ruso

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I use scrap granite from a sink cut out. It's flat and it was free. Overkill at 1 1/4" thick but functional.
Where one can be found? I hear scrap this scrap that all the time. However, unless you are in the business or know somebody who is in - where do you get it for free? Even scrap wood cost money in Home Improvement stores.
 

inferno

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you can also use steel or wood...

and yes i can confirm that a sander upside down and some good paper (cubitron) is a lot faster than stones.
a small hand held belt sander for wood is also A LOT faster. i got mine for 30€, made 3-4 knives with it so far.
 

parttimevegan

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belt sander is for garbage axe head restorations. this job requires flatness that can not be achieved as easy with a belt sander hand held. that ebay link looks like the best cheap option. that czar kasfly looks really good though. do you use silicon carbide, aluminum oxide? what kind of sand paper do you use for carbon steel cleaver?
 

Dendrobatez

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You can get glass platens on a bunch of sites for under $50 if you want granite you'll have to spend a bit more, i think grizzly makes a decent one for $60.
Depending on the paper sometimes a couple drops of water is enough on glass, sometimes you need to use the thin double stick tape. For heavy work you'll want ceramic sandpaper, for the higher grades you can generally start using cheaper varieties.
 

rocketman

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I am in the Houston area, and several times I have just gone by a granite yard, showing granite for home construction, and they always seemed to have pieces lying around . A little smile and a little BS, and I go away with some nice pieces...Once one was kind of irregular, and I stopped by a place that did granite counter fabrication, they cut it to my size for a few bucks. Approximately 2'x2'.
I have a couple of granite surface plates for my machine shop, and would never even consider using one for attaching, or laying sand paper on. For precision measuring only.
 

Desert Rat

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I am in the Houston area, and several times I have just gone by a granite yard, showing granite for home construction, and they always seemed to have pieces lying around . A little smile and a little BS, and I go away with some nice pieces...Once one was kind of irregular, and I stopped by a place that did granite counter fabrication, they cut it to my size for a few bucks. Approximately 2'x2'.
I have a couple of granite surface plates for my machine shop, and would never even consider using one for attaching, or laying sand paper on. For precision measuring only.
This right here. Granite counter top suppliers or installers. Its just a waste product that they have to throw away. Simply ask nicely.
 

Up_dog128

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I have many 10x3", .25" thick glass plates that I had cut at a local glass shop, with the edges smoothed. I'd be happy to send you as many as you like for $4 each plus shipping. Or I could go get more cut to whatever size you like, as I live 8 doors down from the shop. PM me if your interested
 

Bert2368

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1/4" thick (also called double strength) "float plate" glass is relatively cheap at a hardware store and quite flat enough. It is made by pouring out molten glass onto a trough full of molten Zinc, as opposed to "ground plate" which has been mechanically ground flat & smooth, the ground plate is a lot more labor intensive to make and expensive.

I have several pieces of this glass in various sizes for backing sandpaper.

I also have some left over 12" X 12" polished granite floor tiles, these are plenty flat enough for flattening stones and cost less than new glass, also a bit less brittle.
 

Yet-Another-Dave

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Woodcraft often has small granite surface plates on sale. Way flatter than you need for this and more expensive than something for free, but still not too bad and easy enough to source (in the USA.) I just received their May flyer and, from 5/1 to 5/31, they will have a 2" x 9" x 12" plate on sale for $30. If you're interested check their website Friday when it goes live.
 

inferno

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parttimevegan did you get any slab to sharpen on yet?

when you do. try out SiC paper. I can get about 10-15 minutes out of a p120 grit paper (dry!), if i use them wet they stop cutting very fast.
also bosch metal papers seems to do fine. i just wrap them over a stone though. and put it in my stone holder.

when you get tired of doing it manually. you can check out "i bought a sander" thread. but the sander needs better papers. cubitrons. otherwise they wear out in seconds. no kidding.

also the small hand held belt sanders can be very high precision, its basically up to the operator. it has a flat plate as backing.
 

parttimevegan

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I have tried 60 grit sandpaper before. I will take your advise to start with 120. I just need to flatten it enough to polish it on the 320 stone.
 

Up_dog128

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parttimevegan did you get any slab to sharpen on yet?

when you do. try out SiC paper. I can get about 10-15 minutes out of a p120 grit paper (dry!), if i use them wet they stop cutting very fast.
also bosch metal papers seems to do fine. i just wrap them over a stone though. and put it in my stone holder.

when you get tired of doing it manually. you can check out "i bought a sander" thread. but the sander needs better papers. cubitrons. otherwise they wear out in seconds. no kidding.

also the small hand held belt sanders can be very high precision, its basically up to the operator. it has a flat plate as backing.
I agree that wet paper doesn't cut as fast, but I attribute that to the lubrication provided by the water (the same holds true when wet sanding wood). But I have found, both with my belt sander and with hand sanding, that when the paper isn't cutting as well initially it is usually due to loading; if I clean the paper with soap and a toothbrush, or an eraser, it perks back up and gets back its bite (once it dries). I don't have enough experience yet to understand how quickly the different steels take to wear out the paper relative to one another, and I'm sure that it's a factor what with the different carbides and all, but I'm curious how significant it is...
Also, I've been using non-padded, double sided carpet tape to attach sandpaper to glass recently and have found it to work well enough in most applications; you just gotta make sure to have an even backing of tape on the paper
 

Barashka

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I used an oversize glass tile for a kitchen backdrop ... sample too, so half price or smth.
Used carpet tape to attach sandpaper to both sides (cut from 12x12 sheets).
It worked shocking well ... and didn't feel horrible. In fact, the carpet tape provided some buffering and it altogether wasn't dead-glass-feeling.
However, these only let you do edge trailing strokes.
The sandpaper also has a limit, but it's kinda high for the cost, you get probably 5 sharpening sessions x 3 strips from a 12x12 sheet for my size of the tile. It's really not a bad way to sharpen on a budget. Higher grit loaded up faster, so for you with 120 grit it might work quite well for the cleaver ... granted power-something might work even better.
 

parttimevegan

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I just got a machete with a serious lack of anything good on the factory grind. Thinking about building a professional vertical belt sander with adjustable speed. I will probably get a piece of glass for flattening the cleaver. I will PM later. Way too busy to start any sharpening projects right now. I have been retooling the shop for electronics manufacturing and research.
 

The Edge

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I use a cheap piece of 12"x12" tile I got at the home improvement store. It's granite, and pretty darn flat. I was gluing sandpaper to it, but it was a pain to remove, clean and reapply. Picked up a trick from another maker; glue down a sheet of sandpaper, but don't use that. Instead, put the sandpaper you plan on using over that one, and the grit from the one underneath helps keep the one on top in place. Works quite well, though most of my time is used to finish wood on this, and not really used for the steel itself. For flattening of metal, I use a surface grinder, or the disc sander. The disc sander works on stones too, though it will eat through a sanding pad pretty fast.

A cleaver is a lot of work, and not sure why you would need perfectly flat sides, other than a personal goal. The only thing that would need to be that flat, is the tang if you were looking to replace the handle, but that's just an opinion, so take it with a grain of salt.
 

Bert2368

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I just got a machete with a serious lack of anything good on the factory grind. Thinking about building a professional vertical belt sander with adjustable speed. I will probably get a piece of glass for flattening the cleaver. I will PM later. Way too busy to start any sharpening projects right now. I have been retooling the shop for electronics manufacturing and research.
Could you post the make/model of your problem machete and some pictures of that machete showing the bad grind? I would like to see how a machete maker managed to do it wrong.

My younger brother used to be a part time vegetarian- His system was simple: He only ate meat if other people paid for it...
 

Desert Rat

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I just got a machete with a serious lack of anything good on the factory grind. Thinking about building a professional vertical belt sander with adjustable speed. I will probably get a piece of glass for flattening the cleaver. I will PM later. Way too busy to start any sharpening projects right now. I have been retooling the shop for electronics manufacturing and research.
The easiest way to deal with a machete lacking fancy equipment (and even then it's debatable) is to take a file to the edge, followed by stones also taken to the edge rather than taking the blade to the stone.
 
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