Thread: Honing with Salt Water

Originally Posted by Steve56

Salt - sodium chloride - is very bad for both carbon and stainless steels because chlorine/chlorides bond strongly with iron. IOW, the chlorine removes the iron from your steel. Chlorine, especially hydrochloric acid, can eat holes in stainless steel, rust every ferric thing in sight, and is just generally nasty to steel.

I do platinum photographic printing, and the platinum/palladium salts are initially bound to ferric oxide (basically rust). Once you've developed your print, the remaining ferric oxide must be removed, and a 1-2% hydrochloric acid does that almost immediately and must then be neutralized in a sequence of alkaline baths so the paper will last.

As a general rule, you must avoid all acids at all costs when dealing with razors, whose edges are so thin that they cannot stand any insult, shaving is bad enough.

There was a thread on another forum where a noob cleans his razors in soda pop (phosphoric acid). He left a nice vintage razor in and it turned black (iron phosphate) and ruined the razor.

I also polish knives with Japanese natural waterstones. I have seen tap water discolor fresh steel, and sword polishers in Japan frequently add a bit of bicarbonate of soda to the water to ensure that it does not discolor the steel.

NO ACIDS, NO CHLORINE! EVER! Keep your water alkaline.

Cheers, Steve

Interesting that you bring up old photographic processes with this. As I recall, one of the tricks to stabilizing a salt print was to dip it in something like a 2% to 4% sodium chloride solution before moving to the hypo. This was to lift off most of the unexposed silver chloride so that the hypo did not exhaust itself in having to serve the same function. From Wikipedia, I read that sea water ranges to approximately 3.5% saline, so such a solution would appear to have been approximating it. There I also read that sea water has a typical pH range of 7.5 to 8.4, so that would make it mildly alkaline, no?

Originally Posted by bouschie

I would not do it. I live on the beach in Florida and assure you salt water is highly corrosive to steel. Up north where they use salt to melt snow it breaks down concrete and stone. I would be concerned of the effects on razor and hones.

I think it's the water getting down into the porous road surface and re-freezing there that causes it to break down. Water expands when frozen, solid materials don't like this. I'd be less worried about the stone than the razor.

My big concern would be rust. Old high carbon steel blades don't even care for being left in a humid bathroom after a hot shower, I can only imagine what salt water would do to them.

I'll just echo what everyone else here has been saying... saturated or over-saturated, avoid using saltwater on carbon steel especially. no matter how clean and dry you may think you've gotten your blade you risk some serious flash rust and then long-term oxidation beyond that. Stainless will hold up better, but in either case it's neither "good" for the blade, nor beneficial to hone with i wouldn't think.

Originally Posted by Brontosaurus

Interesting that you bring up old photographic processes with this. As I recall, one of the tricks to stabilizing a salt print was to dip it in something like a 2% to 4% sodium chloride solution before moving to the hypo. This was to lift off most of the unexposed silver chloride so that the hypo did not exhaust itself in having to serve the same function. From Wikipedia, I read that sea water ranges to approximately 3.5% saline, so such a solution would appear to have been approximating it. There I also read that sea water has a typical pH range of 7.5 to 8.4, so that would make it mildly alkaline, no?

OT but I believe you're thinking about a stop bath to neutralize the developer in film processes. Developer depletes the fixer. Most folks just use plain water but a little citric in the pre-fix wash IIRC will help.

In platinum print making, the developer is not exhausted and actually gives a warmer tone with continued use. I use potassium oxalate and the light sensitized ferric oxalate on the paper is converted leaving Pd/Pt metal, but the non-exposed ferric oxalate must be removed because it is still UV sensitive. Anything that chelates iron works, like citric acid or EDTA, but 1-2% hydrochloric works really well. It must be neutralized with a base solution wash.

Bottom line, many acids and chlorides remove iron or convert iron to compounds we don't like on our razors, like iron oxide (rust) and iron phosphate (from phosphoric acid as in cola) which is protective but black. Bluing on guns does the same protective function and some razor tangs were blued or blackened. I have modded Gold Dollar with a 'blackened' blade which is actually pretty neat.

Cheers, Steve

Originally Posted by Steve56

OT but I believe you're thinking about a stop bath to neutralize the developer in film processes. Developer depletes the fixer. Most folks just use plain water but a little citric in the pre-fix wash IIRC will help.

In platinum print making, the developer is not exhausted and actually gives a warmer tone with continued use. I use potassium oxalate and the light sensitized ferric oxalate on the paper is converted leaving Pd/Pt metal, but the non-exposed ferric oxalate must be removed because it is still UV sensitive. Anything that chelates iron works, like citric acid or EDTA, but 1-2% hydrochloric works really well. It must be neutralized with a base solution wash.

Bottom line, many acids and chlorides remove iron or convert iron to compounds we don't like on our razors, like iron oxide (rust) and iron phosphate (from phosphoric acid as in cola) which is protective but black. Bluing on guns does the same protective function and some razor tangs were blued or blackened. I have modded Gold Dollar with a 'blackened' blade which is actually pretty neat.

Cheers, Steve

Yes, off-topic, but interesting nonetheless. A salt print is normally printed-out, so development, or stopping it, isn't the issue. In this case, the salt bath is used in a similar way to hypo (sodium thiosufate), as a reducing "pre-fixer" rather than a stop bath. In the early days of photography, a strong salt solution was even used in lieu of fixer, or as a temporary "fix" when travelling.

Rather than a salt solution, which is mildly alkaline, a traditional stop bath is acidic, made from acetic acid or citric acid. This is to stop or neutralize the alkalinity used to accelerate the developing agent's action in a developing solution.

If one really wants to reek havoc on a carbon steel blade, citric acid or lemon juice might be the ticket. This will combine with the steel to create ferrous citrate, which is light-sensitive and will blacken everything. I'm still wondering about the relative feebleness of a 2-4% sodium chloride solution in comparison. Guess I'll have to give it a shot with a beater razor to find out.

Update. We had a small carbon steel kitchen knife that needed a touch-up prior to tonight's meal. So I put approx. 1g of French sea salt into 30ml Vosgian tap water to approximate sea water. 10 mins. honing under halogen light in the bathroom on a mottled piece of Vermont slate, recalling that VT slate does not seem to be affected by Cape Cod sea breezes all that much. A little more honing and the blade, in addition to the edge, started to brighten a little, coinciding with a hidden photo-etching starting to reappear. The edge passing the TNT, I wiped it off completely (not wanting to rinse off the brine) and took it out under cloudy, ultraviolet light. Here, the blade appeared far more tarnished in places, moving to blue in isolated areas. Returned to halogen light where tarnish did not seem so evident. Wiped off the stone and continued honing with jojoba oil as an approximation for whale oil. Wiped off blade and took it out again to the ultraviolet light where the blade seem tarnished and mildly oxidized, whereas the bevel and edge were quite shiny. Edge passing cut paper test. Several minutes later and things seem pretty much the same, with original machining scratches and photo etching on the blade being more pronounced than in starting out.

The reappearance of the photo-etched lettering seems reminiscent of ferric chloride's use in retrieving the effaced date from old coins. A salt solution being mildly alkaline in itself, and hence essentially benign, and a ferric chloride solution being acidic, and therefore detrimental, what may be happening is that the production of swarf, or contact with the carbon steel surface, is creating an acidic solution in the end due to iron release combining with the chloride.

My conclusion is that a salt solution is indeed detrimental to the honing process, as has been the resounding opinion as expressed. Thanks to all for your replies and for your patience in my inquiries.

Originally Posted by Brontosaurus

My conclusion is that a salt solution is indeed detrimental to the honing process

Thanks for the update. I am glad to see that you didn't run the experiment on a good razor first!

Hahaha! Well, interesting to see the results put to the test.

I seriously doubt you'll hurt most stones with salt water. I've got a few rocks I picked up from Pugett Sound years ago that were in mighty fine condition considering they were submerged in the salt water there for most likely a few million years give or take. They look real nice in the bottom of my (fresh water) fish tank.

Originally Posted by Brontosaurus

...a mottled piece of Vermont slate, recalling that VT slate does not seem to be affected by Cape Cod sea breezes all that much...

I'm not sure what your point here is, but I feel I should point out that no part of Vermont is within 120 miles of Cape Cod, and the closest quarry would be more like 160 miles. The big quarries in the Barre area (I used to live across the street from Rock of Ages) are pushing 200 miles, and are at a mean altitude of about 1500 feet above sea level.

Now that we have all given our caution and warning...
Have fun and if you play with it let us know.

A natural slate and an expensive modern man made hone pose different risks.
To me the largest risk I see is when the hone drys.
Not all hones can be soaked forever. Example: a Chosera Stone and many
splash and go hones should not be kept in a bucket of water for months on end.

As for salt, acid and rust do not ignore the micro cracks that black devil spit
rust can move into when old celluloid scales begin to break down and bathe
the blade in acid fumes.

Now I am off to burnish an Arkansas Black and perhaps my uncertain grit chinese
rock thing with the flat surfaces of an old kitchen knife and flat lap slurry from
a 10K chosera (with crazing cracks).