I tried to make my own using a recipe used for sharpening stones, it mimics sandstone, you make a 0.8:2:5 mix of water to cement to sand and it cures soft and abrasive enough to abrade steel. But it just crumbles with any pressure.
The serious wheels with aluminum oxide, how are these made? Are these bonded with a resin, cement, sintered? How?
Not exactly it but this was kind of informative
I imagine the process is similar
>it cures soft and abrasive enough to abrade steel. But it just crumbles with any pressure.
Ever think about changing the cement ratio? Using different abrasive media? Using different types of cement? Basic scientific method, get it together OP.
>Ever think about changing the cement ratio?
No, and i dont plan to. Pure cement isnt very strong, its just a binder. Pure cement can be scratched with a fingernail.
>What kind of rpm’s are you trying to spin the thing at?
For a sandstone the RPMs are low, these are just used to sharpen knives. Indeed something else is used for grinding wheels and it isnt just a change of abrasive media I used washed sand, its still hard, just not as hard as alumina.
Grinding wheels are advertised as having many bonds such as "rubber" and "vitrified"
Would a binder of epoxy count as "rubber"?
>Would a binder of epoxy count as "rubber"?
"Rubber" is an amorphous polymer above its glass transition temperature, so it becomes softer and more pliable than a conventional solid. Most epoxies are formulated to have the glass transition temperature above the expected use temperature, but that can be tuned depending on the chemistry and curing parameters. However, "rubber" in this context usually refers to natural rubber (polymerized latex, a plant-derived mix of isoprene and trace chemicals). It's typically mixed with sulfur, formed to its final shape, then vulcanized.
What kind of rpm’s are you trying to spin the thing at? My monkey brain thinks there’s no way they’re using cement for bench grinder wheels. It has to be something a little more so it doesn’t crack and throw a jagged chunk at the user.
Cement has practically zero tensile strength. Don’t spin such a thing at high RPMs.
Handheld Grinder wheels use resin to bind the aggregate and have several layers of fiberglass mesh for reinforcement.
Probably just expoxy, alumina, and some squeezies.
They're almost invariably resin bonded or vitrified.
Resin bonding is exactly what it sounds like. Some polymer is used to hold grains of abrasive together. The type of polymers used vary quite a bit, depending on application. Resin bonded wheels, due to their fairly flexible matrix, are more tolerant of rough handling and impact. They're the go-to for things like angle grinder wheels and cutoff discs (often with fiber reinforcement).
Vitrified wheels are held together with some kind of ceramic binder, and solidified via firing at high temperature in a kiln. Like resin bonding, the matrix material used in vitrified wheels varies depending on application, with the primary variable being hardness. Harder wheels wear slower and hold their shape better, but the stronger grip on the abrasive means the abrasive particles wear and dull rather than fall out to expose new grain. Softer wheels, conversely, wear faster and allow new grain to be exposed more easily, making them more suitable for harder materials that tend to quickly dull the abrasive particles.
I knew an old boy who was using a bench grinder and his wheel disintergrated while he was using it. Dispite him having his prescription safety glasses on he still lot an eye and his other one was 50% fukd. Buy us or euro made wheels and wear a face mask plus polycarbonate safetys. There is an enormous amount of centrifugal energy in those heavy arse wheels.
>sand
never use sand,
when grinding wheels were still made from sandstone silicosis was common for workers grinding things.
her and old dude just chiseling a grinding stone out of a mountain
Please don't do this anon, you will have a nice day.
But why? A grinding wheel costs like $20 to $50. By DIYing it you risk your life and your grinder, all to save a tiny amount of money.
I have some fears of being cutoff from grinding wheel supply
No, you're just moronic and bored. Fricking own that.
No its true, i might move to a third world country where supply chains are unstable
No, you don't and if you really did you'd know you can buy a lifetime supply cheap with some opportunistic shopping then have less time, effort and money involved. Best way to hunt abrasives is at liquidation auctions. That's where my amateur and pro machinistbros get wheels for their tool and cutter and surface grinders. I buy sanding belts for big sanders to split up for emery cloth strips and score many other abrasives like flap wheels.
You didn't use a search engine.
>No, you don't and if you really did you'd know you can buy a lifetime supply
Yes i do, and i m doing the lifetime supply thing, though its hard to know what counts as enough. I have over 100 small wheels, not of the bench grinder types.
I just wanted to know how feasible it was to make my own if i had to for the reasons i stated. I have seen that cement and sand work but only at low RPM and are only good for sharpening.
Some thicker wheel production, but you don't have a high use rate or you'd already have solved that problem of necessity.
Now post YOUR grinder with timestamp ya c**t.
>Some thicker wheel production,
Irrelevant israeli video that doesnt show anything interesting, gee "computer aided powder mixing" much technology
I have no idea and I don’t give a shit. You still get a bump out of the deal and a pointless yet related story to boot.
>picture it. Decatur Illinois, 1998.
>young buck, 18
>get job at Wagners
>it’s a foundry, car parts for Chrysler
>built like brick shithouse
>put me on grinding line
>grinding wheel roughly 18” tall
> actually composed of three grinding wheels with thin metal discs in between joined into one wheel
>had very little sleep before orientation cuz life long insomnia
>very punchy
>hear story about someone forgetting to set parking brake on forklift and getting off
>forklift rolls back pinning worker to spinning wheel
>man literally loses his ass
>hold back laughter because I’m a stupid ass kid with no sleep
>first day on grinding line, meet beast of wheel
>old timer grinder missing fingers
>not shit funny anymore
i tried my hand on making a 80k grit barber hone once, but when wet it would wash out the grinding media making a mess
What did you use as a binder?
Interesting story
Ill give it another try but this time instead of cement ill use epoxy resin. Then as a last attempt i would try sodium silicate, beyond that i would have to try sintering and i dont have an oven for that kind of temperature. I read on a website that iron oxide and coke can be used as binders, dont know why coke would be used.
bone glue, just as its used on the leather wheels.
why? bone glue is very runny, and as long as it is heated above 50°c it will not harden.
Both important parameters when you try to wet that fine of a powder.
Once through hardened which can take a long time it takes hours of water exposure to soften again, but the drying process warped my bar which required wet sanding and i guess the middle wasn't cured after a week. I guess building up a block by applying some each day for a week would have been better than casting a bar.
I heard of shellac bound hones before, some mid 19th century shit. might give that a shot, only need to weld a mold.
you Defnitly should add support particles, like if you aim for a 500 grit stone you need some amount of smaller scaffolding particle to fill up the gaps. All commercial waterstones do that, play a big role in friability. Search for sphere packing.
>coke
iron oxide and coke reduce to carbon rich iron at a way lower temperature than the melting point of iron itself, maybe that fuses the grains together
oh and if you really are interested, in solingen back when very fine and sharp grindstones were prohibitive expensive, they used to coat hard leather and felt disks with a mix of bone glue and abrasive. 5-10 coats applied, the resulting work surface is rock hard. They used tallow as lubricant.
tried it myself once, dont see why it wouldnt work with more coarse grain