waterstone grit contamination?

[Herv Peairs]

I have the three Nortons: 1000, 4000, 8000. I keep all three in one of those plastic hospital wash basins, submerged, standing on their sides. I rinse the higher grit stones before using with a water spritzer but I'm wondering if I should be using separate tubs.

When I turn a burr at 8000, the bevel is like a mirror but there are still occasional deep-ish scratches that look like 1000 grit scratches. I believe my blades also fail at these points, creating micro divots in the edge, perhaps causing a return to the sharpening station before I should need to.

I also place each stone on the same surface when sharpening.

I've seen pictures of "ponds" with multiple stones in them, but hmm.

What do the experts do to avoid grit contamination?

Thanks, Herv

[Nicholas Lawrence]

Not an expert, but I have a Norton 1000/8000 combination. For soaking both sides obviously go in the same tub together. For sharpening, I start with the 1000 and then just flip it over. Never seem to have any trouble.

I will say my 1000 does not leave anything I would describe as "deep scratches."

What happens after you flatten them?

[Jim Belair]

Also not an expert but I'll answer anyway. I keep my 1000 and 4000/8000 stones in separate containers, more due to the size of the container. While I usually wipe the blade when moving from 1000 to the finer grits I don't obsess about it. Edge failure at any 1000 grit scratches seems a stretch to me.

[Patrick Chase]

Also not an expert but I'll answer anyway. I keep my 1000 and 4000/8000 stones in separate containers, more due to the size of the container. While I usually wipe the blade when moving from 1000 to the finer grits I don't obsess about it. Edge failure at any 1000 grit scratches seems a stretch to me.

I use shared containers with waterstones up to the Sigma Power 13k (which is a vastly finer stone than the Norton 8k) and don't have any problems with cross-contamination. Just flush the finer stones with fresh water before you use them (from a squirt bottle for example) and run your finger over them to check for any "stuck" grit. It's pretty easy to feel if you've got something as coarse as a 1k grit in there.

Cross-contamination is simply not much of an issue with waterstones in my experience. Lapping films (diamond, AlOx, etc) are similarly simple to deal with.

Contamination is MUCH more of an issue with diamond pastes, because with those you can't flush the surface any time you feel like it. Once you have contamination you have to remove all of the existing compound from the lapping plate and possibly re-surface the plate as well.

[Herv Peairs]

I appreciate the answers. With respect to the flattening question, that doesn't seem to matter other than I generally empty the tub and add fresh water as part of flattening, so things are likely to be cleaner. I just flattened them today in fact. I did learn as part of today's research that Norton is said to recommend not to soak the 8000 so I am removing that one from the tub. I'll keep flushing with the squirt bottle per Patrick.

Maybe I'm not spending enough time on the 4000 to get all the 1000 grit scratches out. I concentrate on the burr and maybe I should be looking more at the scratches.

[Stanley Covington]

Using a single tub can be a problem, in my experience, when trying to produce a super-sharp and super-beautiful edge. For this reason, I don't use a tub at all. However, for practical sharpening, I don' think you should have to worry too much.

Contamination from dirty water can be avoided by using clean water from a bottle to wet stones instead of scooping it from a tub of muddy water. I responded to another thread on Nagura recently and gave the basic formula for sharpening water.

The water spritzer you mentioned is good enough to wet dried stones, but not adequate for washing stones. You need enough running water to flush the grit off. A few handfuls of clean water may suffice. A hose or tap would be better. I don't like spray bottles anyway. My sharpening station is very crowded, and a spray bottle gets mist everywhere including dry blades and tools resting nearby. A plastic wash bottle (the kind with the bent tube) works best, IMO.

A very common culprit for grit contamination is transfer of mud from one stone to the next by the blade. It is easy to leave a bit of mud on a blade's corner. This can get embedded into the next stone in the progression, and mixed with the mud causing ongoing problems. Clean the blade thoroughly before moving onto the next stone. Do a final wipe on a clean, white paper towel that will easily show mud.

If you suspect contamination has occurred, wash the stone in clean water, work the face with a nagura, and wash it again to remove mud and any embedded grit. Sometimes I use a brush to scrub my stones. Be sure to touch up the bevels at the stone's edges, and to clean the dried mud off the sides.

Dust and airborne grit can quickly contaminate your stones, and is often very hard. This is especially a problem on dusty jobsites, near roads (even paved, apparently clean roads are inherently dusty, and passing cars kick up dust), or in desert areas like Southern California or Nevada. Keep your stones covered when not in use. I wrap mine in newspaper. Try to keep dust down when sharpening. Splashing water on the ground or concrete floor around your workplace helps.

Stan

[Patrick Chase]

Using a single tub can be a problem, in my experience, when trying to produce a super-sharp and super-beautiful edge. For this reason, I don't use a tub at all. However, for practical sharpening, I don' think you should have to worry too much.

I think your answer is spot on, with perhaps one clarification: The OP states that his finest stone is a Norton #8000, which is a 3 um synthetic stone, so he's clearly not going for super-beautiful (and there's absolutely nothing wrong with that - plenty of people prepare tools that produce terrific work with that stone). He should be able to feel and easily flush away any grit large enough to significantly compromise that stone's performance. If he's said he was ending on a #30000 JNat or something like that I would have changed the emphasis of my response to look more like yours :-).

I should have been clearer that when I said "flush with a squirt bottle" I meant the kind that shoots a pretty decent stream. I use a fairly fast-flowing 32 oz lab bottle, and I probably use several oz when I flush the surface of a stone.

Stanley also rightly points out that the water is but one of many possible contamination paths. The tool is a classic contamination "vector", as is your skin (my personal bette noire and cause of much grief). When I'm working with fine diamond I often wash my hands between grits.

[Stanley Covington]

I think your answer is spot on, with perhaps one clarification: The OP states that his finest stone is a Norton #8000, which is a 3 um synthetic stone, so he's clearly not going for super-beautiful (and there's absolutely nothing wrong with that - plenty of people prepare tools that produce terrific work with that stone). He should be able to feel and easily flush away any grit large enough to significantly compromise that stone's performance. If he's said he was ending on a #30000 JNat or something like that I would have changed the emphasis of my response to look more like yours :-).

I should have been clearer that when I said "flush with a squirt bottle" I meant the kind that shoots a pretty decent stream. I use a fairly fast-flowing 32 oz lab bottle, and I probably use several oz when I flush the surface of a stone.

Stanley also rightly points out that the water is but one of many possible contamination paths. The tool is a classic contamination "vector", is your skin (my personal bette noire and cause of much grief). When I'm working with fine diamond I often wash my hands between grits.

Patrick

In that case, we are in full agreement.

Cheers.

[Stewie Simpson]

The most undated contaminants on your water stones are caused by loose hair follicles and dry dead skin landed on the top surface of your water stones. Before I sharpen my blades, I make I shower twice, the slip into a pair of 3M full body disposable paper overalls, a hair net, a full faced Racal Helmet, and a fresh pair of disinfected rubber gloves. I make sure I only use demineralised water as a lubricant on my stones. Where applicable, the timber that's to be worked should undergo high vacuum pressure to remove any loose foreign impediments on its outer surface, before being wiped down with a powerful disinfectant. I make allowances within my diary to commit at least 8hrs of prep work before the tool actually makes contact with the wood surface. Less time is needed if your just working the cutting edge on a leather strop.

[Malcolm Schweizer]

It sounds to me that you just need to spend more time on the 4000. The 8000 mirror polish really shows up those little ones you missed.

Definitely do not store the Norton 8000 in water. It gets soft- I know from experience.

[Herv Peairs]

The most undated contaminants on your water stones are caused by loose hair follicles and dry dead skin landed on the top surface of your water stones. Before I sharpen my blades, I make I shower twice, the slip into a pair of 3M full body disposable paper overalls, a hair net, a full faced Racal Helmet, and a fresh pair of disinfected rubber gloves. I make sure I only use demineralised water as a lubricant on my stones. Where applicable, the timber that's to be worked should undergo high vacuum pressure to remove any loose foreign impediments on its outer surface, before being wiped down with a powerful disinfectant. I make allowances within my diary to commit at least 8hrs of prep work before the tool actually makes contact with the wood surface. Less time is needed if your just working the cutting edge on a leather strop.

Great advice, thanks. I also have plans in the works to replace all the harmful reactive air in my shop with an inert gas (dried and filtered). I'm down to argon or xenon. Any recommendations?

[Stewie Simpson]

Thanks Herv; I have no experience dealing with inert gases, such as argon and xenon. If you could do a follow up post on the best way forward to address harmful reactive air, it would be appreciated.

regards Stewie;

[Stewie Simpson]

I should have mentioned that my father, and his father before him were taught to just spit on their sharpening stones, and spread it evenly across the full surface of the stone before use. Unfortunately, I am unable to provide enough spit to carry on that early tradition, and have been forced instead to used a squirt bottle. Before I was born, my father completed his 3 years of national service during the late 1950s as a Sapper on Christmas Island when Britain were forced to carry out their own Nuclear Tests. Its possible, as a result, I inherited some sort of genetic mutation caused by my fathers exposure to high levels of nuclear radiation.

Stewie;

[Stanley Covington]

The most undated contaminants on your water stones are caused by loose hair follicles and dry dead skin landed on the top surface of your water stones. Before I sharpen my blades, I make I shower twice, the slip into a pair of 3M full body disposable paper overalls, a hair net, a full faced Racal Helmet, and a fresh pair of disinfected rubber gloves. I make sure I only use demineralised water as a lubricant on my stones. Where applicable, the timber that's to be worked should undergo high vacuum pressure to remove any loose foreign impediments on its outer surface, before being wiped down with a powerful disinfectant. I make allowances within my diary to commit at least 8hrs of prep work before the tool actually makes contact with the wood surface. Less time is needed if your just working the cutting edge on a leather strop.

What, no air shower? No walk-off mat? No cleanroom vacuum?

[Stewie Simpson]

Stanley; I am sharpening an iron to work some wood, not building parts for NASA. Its matters jacky chan to me if there is a bit of dust or contamination from the previous stone worked. If its a water stone, flush the top surface with a squirt bottle and get on with it. If its an oil stone, squirt some oil on the top surface and get on with it. A woodworkers workshop was never meant to be a dust free environment. imo

Stewie;