Thread: A bit of sharpening sacrilege to brighten your day.

yessir on the substrate. Just as I mentioned with the bonding grade diamond, the charge can really be anything hard enough to work over the steel. Diamond is convenient if you're sharpening something that has no business at all on a stone, but the feel of an arkansas stone as the substrate is better than anything else, far and away, and it will very infrequently need addressing in terms of flatness.

I haven't used alumina only because I think shaptons is probably more expensive than bonding grade diamond - 100g of 1-3 micron bonding grade diamond is about $15 out of china and it will mangle 10V carbides like nothing and cut them like a clean moldboard plow.

I do have a pound of whatever the linde is that's 0.3 micron - far too fine for any practical use and I've now forgotten what I was trying to do - probably thinking of trying to make a very fine sharpening stone with resin. I did try that - epoxy is grabby and not resilient to tools at the same time, a bad combination.

you're getting into territory that I mentioned - the more time you spend with the natural stones and the india, the more ways you're going to find to use them that you can't really use other stones. it will improve your results and cut your time sharpening and faffing with stones at the same time.

Yeah, this was a bottle I got on deep clearance years ago. I thought it was going to be like Clover fine (~300 grit) and then I looked it up and it was actually 4000 grit. It's been rolling around in the bottom of a box, still in the sealed plastic bag from Shapton ever since.

The interesting thing is how little it takes. I put on less than 1/8 teaspoon, and I could probably still have used half as much. All it takes is a teeny shake. I suppose that makes me appreciate how little grit is needed to do the cutting vs how much is required to make a rock that doesn't fall apart. I suppose that's the story with diamond plates, though.

I'm going to get some 500 grit SiC to juice the India stone, as the Shapton coarse is WAY too coarse for what I want. Turns out the stuff is pretty cheap as "Rock Tumbling Media." Go figure.

oh yeah, it's a very small amount.

if it's diamonds, it's literally like what you can pinch between two fingers and not too much more than that and sprinkle it on like pixie dust.

At 4000 grit, you don't have to worry too much about slurry dulling, but with more aggressive grits, too much on the surface creates a layer that's working more like cake icing with grit in it and rounding the edge some. Same reason the older japanese stones are so much different on a pretty "juicy" slurry vs. on clear. On clear, they are rowing the steel and on finer, they are making an edge that seems a lot duller than the finish looks.

It's that layer of freshness just at the time but without too much thickness that really makes for aggression, but i do like the tumbling cutting as long as slurry dulling doesn't become too much of a problem - the tumbling type is very constant, it does what it is going to do for a while whereas a thinner layer will require sooner refreshing.

this is s a pretty good thing for you to have gotten into rather than departing off to another stone. I've used all of them, there isn't really anything better - but it's fair to say the characteristics of ark stones are suitable for a very particular sharpening style - one of bias and working small areas and abrading and polishing to fineness rather than just raising ever smaller aggressive burrs.

The loose grit of whatever you choose allows you to suddenly turn them in to something with the feel of an arkansas and the aggression of anything. That feel is important. As much as I've used other things, like even harder stones or hard cast plates or whatever, the feel really communicates something to you and allows you to control not damaging edges on smaller tools. Feel and action are important, which is why I glow about the frictionite 825. The stone itself is nothing much different in fineness. I wish they'd have shared the recipe and process for how they made it, though, the feel is divine. In the end, I still sold mine. The arks and the buffer have my heart, along with compounds on the upper fine side if it's desired on various substrates.

Originally Posted by truckjohn

Turns out the stuff is pretty cheap as "Rock Tumbling Media." Go figure.

Oh yeah, it's everywhere. Probably up to 55 gallon drums, but I did at least see 5 gallon buckets of it or 50 pounds. I'm sure it's used as blasting media when something really aggressive is needed.

The fact that any of it costs more than a couple of bucks in a tiny jar is just what the woodworking hobby does to people who don't look around. it's probably what it takes for retailers to make ends meet - $10 a gallon honing fluids rebottled to be sold at 200-400 a gallon, buffing bars and honing media that are consumed in great amounts and sold cheaply elsewhere for four or five times the cost to woodworkers. We're easy targets for that stuff.

I joked to Bill Tindall when looking for stuff for varnish that I'm beginning to notice an avenue to success in this world - take something that doesn't cost that much, get it in a big bottle, split it up into little bottles, refuse to tell what it is other than what has to be disclosed on the SDS, market it to people who don't have a clue, and disregard the rest.

the amount of little bottles of flax seed sold for food, etc, but that isn't very expensive at the barrel levels - it's really something.

I'm pretty sure I have a permanent and very high quality amber varnish. I can make a quart in four hours or so that's pretty stiff on the resin side. I see quite a bit of it being sold long oil (easier to stretch the resin further, the resin is obviously the hard part - it won't generally start to cooperate until around 700F and it can catch fire and take off at 800F) and probably with a combination of resins - 50 cents to a dollar per ​ml. (!)

I'm pretty sure soft, mushy long oil varnishes hang around because there's still money in the sailing/yachting world. Outdoor furniture gets some too. Then there's the long history where climate control (aka heat) was only something available to the rich. Everybody else had drafty houses they heated with fire only when it got too unbearably cold. That means zero humidity control. Long oil and spar varnish finishes are gold at that point, as wooden things expand and contract a massive amount when there's giant swings in humidity going from bone dry single digits to condensing, and perhaps even in the same week. Short oil varnishes simply crack and peel off with that.

Not so much of a problem anymore where we live, but people also don't use varnish much either.

Anyway, I'm going to try this abrasive on the stone thing some more to see how it goes. On the up side, it works and I don't spend any more.

Originally Posted by truckjohn

I'm pretty sure soft, mushy long oil varnishes hang around because there's still money in the sailing/yachting world. Outdoor furniture gets some too. Then there's the long history where climate control (aka heat) was only something available to the rich. Everybody else had drafty houses they heated with fire only when it got too unbearably cold. That means zero humidity control. Long oil and spar varnish finishes are gold at that point, as wooden things expand and contract a massive amount when there's giant swings in humidity going from bone dry single digits to condensing, and perhaps even in the same week. Short oil varnishes simply crack and peel off with that.

Not so much of a problem anymore where we live, but people also don't use varnish much either.

Anyway, I'm going to try this abrasive on the stone thing some more to see how it goes. On the up side, it works and I don't spend any more.

Amber varnishes and hard copals that are short oil are definitely long gone. They were replaced by much cheaper synthetic lacquers and enamels. What remains for boat varnishes now as soft varnishes that are synthetic resin is more of a modern thing - not much related to what was used 150 years ago, for example. In the case of older varnishes for interior work, long string and long oil made for a less brilliant but durable varnish. the "cheap" finishes of the day were mostly resin, like 3 parts resin to 1 oil and that stuff was brittle. It was cooked short and fast to get a varnish batch out of a pot once an hour, and the short oil and lead dryer made it brilliant.

I think the copals that were long string and moderate oil were head and shoulders above anything we have now, even for outdoor use on things like carriages -they could be brilliant, durable and non-darkening, but the best of the outdoor varnishes had no dryers in them. Fossil copal would probably be exhausted by now, but even in the late 1800s, the highest grade was $300 a ton. Which was an enormous enormous amount of money. Phenolic resin can be bought now for about $2 a kilo by you or I (it's unstable, though, not a good choice). Hydrocarbon solvents wiped out the turpentine and terpenes industry, and managed to get credibility with the scientific community that the hydrotreated types are more mild. I think they aren't, they're carcinogenic and they make me dizzy. But turpentine is stinky to some people and pleasant to others.

It's an interesting topic - there was sort of a reset button on varnishes so what we have around now isn't anything like what was more common for nice work back then. Too, if you wanted something to hold up really well outside beyond just the bonkers expensive no-drier copal varnishes, the name of the game in 1880 was dark pigment to block the UV light from being able to go through the finish layer.

As much as spar urethanes are touted now, I've never had any on my south facing railing last more than a year without cracking - the sun just eats them up. I'd guess people with boats either do a lot of varnishing or pay someone to do it, too, and the trend now is to pass off UV stabilized polyurethanes on varnish buyers for the same price. it's a great thing for the makers of the finish - they can tout the fast drying of the polyurethane but the reviews aren't quite as good for it -it doesn't level like varnish.

Some of the older more durable fossil resins don't "level like varnish" either! They have so much adhesion, they can start to favor anything and that may not be flowing out.

A couple of my books, though, do reference the light colored short oil copals and others that are made to go on millwork and look bright - whoever applies them has something that would look like lacquer now for a short period of time and seasonal movement leaves it looking like the lacquer on an early gibson guitar covered with cracking.

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back to the stones - yesterday, I received a 80 grit diamond 6x1" finger stone and a 150 grit version of same. they were about $6 total between the two of them with shipping. the coarse one gave up all of its high standing diamonds immediately to the india stone but what is left behind is nice and it livens the stone up a little. But as I'd expect, it's not anywhere close to the brashness of a new stone. i think there's no practical way to bring that back, but it doesn't matter that much - it works well as it is and sprinkling abrasive on the stone in times of fast cutting need is far more practical and costs almost nothing.

I've got some 500-600 grit SiC tumbling media on order as the 90-120 starts off way too gritty. I'm thinking that will be pretty close to right on a fine India stone. I don't want it leaving big scratches, but it still needs to be coarse enough to cut quickly. I halfway wonder if the correctly sized grit keeps the abrasive in the stone alive.

On varnishes... Commercially, copal and fossilized amber are a no-go. They're simply not available in commercial/industrial quantities. I've used a lot of different varnishes over the years. Most of the old stuff used indoors on fine finishes wasn't properly "Varnish" in the crosslinking polymerized finish sense, but rather "Spirit varnish" - a mixture of resins, gums, and solvents that dried to form a shiny finish. While not as durable, their compelling advantage is that they are easily repairable.

After long travails and losing the battle against modern varnishes low VOC formulations which have solvents that give me a ripping headache, I've basically switched to Minwax wipe on poly. It feels like cheating, but such is life.

Originally Posted by truckjohn

I've got some 500-600 grit SiC tumbling media on order as the 90-120 starts off way too gritty. I'm thinking that will be pretty close to right on a fine India stone. I don't want it leaving big scratches, but it still needs to be coarse enough to cut quickly. I halfway wonder if the correctly sized grit keeps the abrasive in the stone alive.

On varnishes... Commercially, copal and fossilized amber are a no-go. They're simply not available in commercial/industrial quantities. I've used a lot of different varnishes over the years. Most of the old stuff used indoors on fine finishes wasn't properly "Varnish" in the crosslinking polymerized finish sense, but rather "Spirit varnish" - a mixture of resins, gums, and solvents that dried to form a shiny finish. While not as durable, their compelling advantage is that they are easily repairable.

After long travails and losing the battle against modern varnishes low VOC formulations which have solvents that give me a ripping headache, I've basically switched to Minwax wipe on poly. It feels like cheating, but such is life.

The same is true for me - the solvents in great quantity - stoddard and naphtha were bad enough. The odd smelling transitional solvents are worse and some of them need an aromatic solvent to thin properly, like xylene, which is downright nasty. With windows open, I still had to wear an OV mask while applying floor urethane. The canned product was like calf slobber and once I thinned it with xylene, the odor was obviously unreal. I've run into a person here or there who likes xylene's smell -but it is so strong in quantity that it convinces your brain that you're still smelling it for a while after.

yes on spirit varnish - shellac and oils were probably pretty common, as well as other spirit types. they don't get as much credit as they should, the same as shellac for practical furniture projects. The oldest shellac-finished stuff I have (from making) is about 15 years old. I've spent somewhere around 10 minutes on each of two pieces during that time period and they look perfect. The damage to them was baby slobber and rings from sweaty glasses or other spills. both are in kids' rooms.

I can't think of a practical need for varnish outside of a kitchen or bathroom - maybe floors, but I think there's a suitable argument for shellac on floors and the fact that more frequent but very easy refreshing of floors worked well for a long time.

it's too hard to get any of the older varnishes that were intended for interior work to be able to tell what the market may have looked like. Pratt and Lambert and other stuff was the tail end of totally adulterated recipes vs. fossil varnishes, and there is actually a small come back of commercially marketed fast drying toluene/polyester alkyds, but the one I tried is very soft (minwax ...can't remember the name now).

polyurethane gets a bad rap for no reason - it's practical, durable and cheap. One of the first things I figured was a wooden lamp base for someone else. I used the wipe on stuff from minwax and followed the directions and it looked super. It's the solvents in the cheap stuff and the low VOC that's problematic, and the film has decent hardness but not great toughness in a thicker layer, but nobody does high build finishes with polyurethane.

the fact that super high cost "hardwax oils" with an isocyanate second part are seen as the it finish now when they are less durable than simple thinned polyurethane...really bizarre to me.

I still haven't used (solvent) arm r. seal, but everyone who has mentioned it to me has discussed how nice it works and how easy it is to brush. I was surprised to see that it just has stoddard solvent and naphtha in it still looking at a recent SDS. Which caused me to go read the EPA rules on VOCs. It's not that expensive just to pay a fee for waiver, but too much for people trying to do battle with buyers at big box stores, i guess.

Solids wise, i can make a tung/rosin varnish for about the same cost, though, and said varnish will never gel in a jar or can.

by the way, i've used 220 grit SC on the fine india, I guess I'd forgotten, but it's at the corner of the shelf right above my bench - i use it when "manufacturing" chisels but have changed my pre-stone process to the point that it's generally not needed. 220 works well in a sparing amount if you find 400/600 to pass through it's strong cutting phase and get too fine quickly.

the only other SC that I have is 400 grit in a paste for refreshing the reel mower, so that's out, and 70/80 grit (way way too coarse).

and 100 grit aluminum oxide (white) that I got a long time ago to try just flattening things. like 15 years ago. Came from soap suppliers. At some point, I'll put it in soap. it's too coarse and it stays coarse.

I think 500 grit is about right. A teeny sprinkle makes the fine India cut really fast and still maintain basically the same baseline transitional grit level.... Interesting that the oily swarf has a slight brownish tint under the black. It seems to be very slightly refreshing the stone as it goes. But yeah, I think SiC breaks down pretty fast.

Next will be some 500 grit Aluminum Oxide. That should more closely mimic the fine india stone.

I'm curious about the Shapton "Fine" stone lapping compound. They call it "4,000" - but I'm guessing that's JIS. This would be approximately equivalent to ANSI 1,200 grit. Charts say around 3-micron... Which incidentally is very close to the claimed abrasive particle size in quality Arkansas stones. The thing I like about it is that it seems to supercharge a soft Ark. It still has the same feel and leaves the same finish as a soft Ark. It just cuts way faster, but it doesn't misbehave like stray coarse grit..

Originally Posted by truckjohn

I think 500 grit is about right. A teeny sprinkle makes the fine India cut really fast and still maintain basically the same baseline transitional grit level.... Interesting that the oily swarf has a slight brownish tint under the black. It seems to be very slightly refreshing the stone as it goes. But yeah, I think SiC breaks down pretty fast.

Next will be some 500 grit Aluminum Oxide. That should more closely mimic the fine india stone.

I'm curious about the Shapton "Fine" stone lapping compound. They call it "4,000" - but I'm guessing that's JIS. This would be approximately equivalent to ANSI 1,200 grit. Charts say around 3-micron... Which incidentally is very close to the claimed abrasive particle size in quality Arkansas stones. The thing I like about it is that it seems to supercharge a soft Ark. It still has the same feel and leaves the same finish as a soft Ark. It just cuts way faster, but it doesn't misbehave like stray coarse grit..

Oh yeah, anything in loose grit that's 3 or 4 micron is going to be a world away from a fine arkansas stone in finish. the edge is just rowed and ragged. I tried 5 micron loose diamonds at one point and you cannot imagine just how bad the edge was. It lasted 2/3rds as long as a 1 micron diamond edge, much less than a hard ark, and it was miserable and dull looking on a planed surface even with a fresh edge.

put it on wood and the result may be entirely different, though. the yellow compound that I like to use looks like this (5 micron calcined alumina) off of a buffer wheel:
https://i.imgur.com/nkFRFve.jpg

Looks like this on corian (relatively hard - apologies, no picture of the edge, but you can see what it does to a wide flat surface- murder):
https://i.imgur.com/B8IQObU.jpg

I don't have a picture of it off of MDF or softwood, but it's 90% of the way to the buffer's finish because the grit just goes into the wood.

To never have a finish stone and use a buffing bar on wood after an india is probably better than most stones, and more practical than many, especially if the bar is like the 5 micron yellow bar that mcmaster carr sells. that's this one. it's got some cutting power and you can game it so that it's cutting briskly or finely - far more useful in actual work than just chasing "fine".

doesn't make much of a burr on softwoods or MDF, either.

I'm now willing to say that if you get a "Dud" soft Arkansas stone, try charging it with Shapton fine stone lapping compound before you toss it. That will rejuvenate the stone without making it cut more coarse or dropping off massively as it settles in. For me, it turned a dud it into something very useful. The cutting power never dropped off as the stone settled in, so long as I used a teeny shake with the oil at the beginning of each session.

So I tried out the cheap 1200 grit aluminum oxide tumbling media tonight. It is not nearly as tightly graded as the Shapton fine stone lapping compound. The cheap stuff both cuts slower, and leaves a more "scratchy" finish. It also contains more than a trivial amount of stray coarser grit. Overall, I'm not a fan of that, especially when 1 little jar is a multiple lifetime supply. Luckily, a good scrub in the sink under hot, soapy water, and it's gone. It might not be bad for knives where you may still want a toothy edge, but not a chisel or plane iron.

A mid-density (2.22), less evenly porous soft and a 6" plastic box Smiths both showed a stark night and day difference between the Shapton compound and the cheap stuff, with the cheap stuff cutting less than half as fast while leaving a scratchier finish.

The other piece of this seems to be the stone itself. Both of those had nearly all the swarf and grit wash out of the stone fairly clean with dish soap and hot water, where a lower density (2.16) but very evenly porous stone is now black on top from swarf that doesn't wash out. I didn't try that one with the tumbling media, as it's my "favorite" with the Shapton magic dust.

Stone wear wise, yes. I would assume it accelerates the wear on the stone. 20 or 30 chisels on the charged low density stone left an ever so slight dish that let light pass when I candled it against a straight edge. At this point, I would estimate less than 0.005" wear. I've got no reason to lap it, but it's there. The trade off is that these stones are now useful, so it's a win even though I will have to occasionally lap out wear

Also, if the stone has a tendency to throw stray grit, it doesn't change that. The thing is, now that it doesn't glaze or go dull, I just wash it off and the stray grit is gone.

Originally Posted by truckjohn

I'm now willing to say that if you get a "Dud" soft Arkansas stone, try charging it with Shapton fine stone lapping compound before you toss it. That will rejuvenate the stone without making it cut more coarse or dropping off massively as it settles in. For me, it turned a dud it into something very useful. The cutting power never dropped off as the stone settled in, so long as I used a teeny shake with the oil at the beginning of each session.

So I tried out the cheap 1200 grit aluminum oxide tumbling media tonight. It is not nearly as tightly graded as the Shapton fine stone lapping compound. The cheap stuff both cuts slower, and leaves a more "scratchy" finish. It also contains more than a trivial amount of stray coarser grit. Overall, I'm not a fan of that, especially when 1 little jar is a multiple lifetime supply. Luckily, a good scrub in the sink under hot, soapy water, and it's gone. It might not be bad for knives where you may still want a toothy edge, but not a chisel or plane iron.

A mid-density (2.22), less evenly porous soft and a 6" plastic box Smiths both showed a stark night and day difference between the Shapton compound and the cheap stuff, with the cheap stuff cutting less than half as fast while leaving a scratchier finish.

The other piece of this seems to be the stone itself. Both of those had nearly all the swarf and grit wash out of the stone fairly clean with dish soap and hot water, where a lower density (2.16) but very evenly porous stone is now black on top from swarf that doesn't wash out. I didn't try that one with the tumbling media, as it's my "favorite" with the Shapton magic dust.

Stone wear wise, yes. I would assume it accelerates the wear on the stone. 20 or 30 chisels on the charged low density stone left an ever so slight dish that let light pass when I candled it against a straight edge. At this point, I would estimate less than 0.005" wear. I've got no reason to lap it, but it's there. The trade off is that these stones are now useful, so it's a win even though I will have to occasionally lap out wear

Also, if the stone has a tendency to throw stray grit, it doesn't change that. The thing is, now that it doesn't glaze or go dull, I just wash it off and the stray grit is gone.

tumbling media is something I'm less familiar with. I like to get lapidary media because those folks just can't tolerate a good even scratch pattern.

I would imagine that shapton would have a relatively even alumina - it's kind of like silicon carbide. if you get a whole bunch of it, you can get finely graded stuff cheap.

But where does the average guy get 8 ounces for 8 bucks. It gets less easy.

I've got linde - I think it's A - there's a 3 micron and a 0.3 micron of white alumina. I have the latter . It's like powdered sugar with air in it - it won't settle, but good god does it polish slowly. and at that fineness, it's no longer really cheap - it was like $60 for a pound - which is 14 lifetimes' worth, but I couldn't stomach paying $20-$30 for an ounce and thought it would be kind of fun to try to make a sharpening stone out of it. Maybe someday. the stone wouldn't be like a stone, but rather a burr chaser and tiny tip polisher for hand rolling an edge. It's a dumb idea that if it had merit, it would be out there already.

Sorry to hijack, but is there merit to putting loose diamonds on a worn diamond plate to rejuvenate the cutting ability? Cheers