[OP]
Member
I am curious how you guys restore old chisels that are full with rust without to go aggressive on them. Especially the back and hollow.
And how about the black color that many Jap. Chisels have. As I see its not a paint but more something permanent. Is there any way to color it?
Any tips and suggestions are more that welcome!
Regards Lambis
Member
I have restored a couple of Japanese chisels my son brought back from Japan. The main issues with them were the rust pits that were near the cutting edge. Once I'd worked the back and hollow fairly clean and had some clear of rust area with in a 1/4 in of the cutting edge, I switched to sharpening the main bevel. The back/hollow area just needs to be
fairly flat and clean and only near the cutting edge. Then concentrate on the main bevel to get a sharp apex edge with no rust or chip outs. I was lucky as both chisels were very good steel and the rust pits that I did work on were not very deep.
I've used both chisels for several years now and both are really good users. They only need a touch up now and then and a brief hone when in heavy use.
Cleaned them with WD-40 using 4 ought steel wool and then a good wipe down with thinned BLO.
I would not worry about the dark hollow areas other than to get them flat at the top of the ridges and not down in the hollows. It's good patina and will continue to protect
the chisel as rust seems to not want to establish it'self there.
Good luck and enjoy the Japanese chisels....well worth the effort to put to use IMO.
Guest
Lambis:The most critical area is the flat side with the hollow. This hollow is called the "Ura." If the rust pitting around the edge of the ura, or down in the hollow is very deep, the blade may be impossible to restore. So for now, let's assume it's not too deep.Make a mark on the handle with a marking pen on the same side as the flat (ura). This will help you get the handle back in the right orientation. Remove the handle. You can do this by holding the blade in your hand and tapping the ferrule (coned piece of steel between blade and handle) on the corner of some wood. Hold the blade so the ferrule strikes the wood at a 45 degree angle to the flat, and rotate it around repeating this. Gradually, the blade should work loose. Don't let it fly off.Take a razor blade and scrape off the rust on all flat surfaces. You don't want to take it down to bright metal, however, just enough to remove the surface rust without scratching the underlaying metal.Use some wet or dry sandpaper and water to remove the rust inside the hollow, and around the neck. Once again, be careful to remove just the surface rust. We don't want bright metal exposed at all.Clean it very well with lacquer thinner and a clean rag to remove rust and oil. Repeat several times rubbing as hard as you can. Finish up with rubbing alcohol to scrub off the remnants of the lacquer thinner.Heat up a tea kettle so that steam is coming out the spout. Grip the blade's tang with vice grips or pliers. Hold the blade in the steam moving it around slowly. You want it to get really hot. The goal is to convert the rust (iron oxide Fe2O3) to a black, hard substance called magnetite (Fe3O4). After 10 minutes or so of steaming, place the blade inside a small, wet, cardboard box with the blade propped up on the flat (hollow) ura on a piece of plastic or metal, anything that won't absorb water. Put the box in the warmest place in your house, and keep it wet. The purpose it to encourage more rust.After 24 hours, remove the blade and scrub off any new rust with a hard bristle brush. A "carding brush" is ideal if you have one. These are just fine bristle stainless steel brushes. But whatever you do, don't use a normal metal bristle brush. A plain plastic or vegetable fiber brush will suffice..Repeat the steaming and rusting and carding process several more times. When complete, the surface should be black. Stop the rusting process by washing the blade in baking soda and hot water, and oiling it with motor oil after wiping it dry.The next step is to lap the flat and ura. You need a lapping plate and grit. A hard flat surface and wet or dry sandpaper will work too. Work carefully but forcefully to create an absolutely flat plane around all four sides of the ura and without any pitting at the cutting edge. Don't overdo this.Work the bevel at this time. You want 28 to 30 degrees, and flat bevel, not a rounded one. Be extremely careful if you use a grinder to avoid overheating. If the blade at any location is too hot to hold, you have probably ruined the temper.After this, simply sharpen the blade, and replace the handle.There are some setup procedures for Japanese chisels which you can find through a search of this forum. They will show you how to bevel the ferrule, trim the blade end of the handle, scallop the neck of the handle, bevel and true the katsura (metal ring at end of handle), and set the ring on the handle. I strongly suggest you follow those before replacing the handle.God luck,Stan
Last edited by Stanley Covington; 11-23-2015 at 7:26 AM.
Member
That's one hell of a description of a blueing (or browning, I never really understood the difference) process using household methods! I suppose you start with rusty iron? I have some items I want to give this black coating and the first thing to do would be making it rusty.
Guest
Kees:If you start with bright, clean steel, the finished product looks better, but for the OP's purposes, this is the easiest way when beginning with an already rusty blade. Of course, you well know that the black coating on forged tools is oxides of carbon and very tough, but others may not know this. In my experience with guns and knives, rust blued finishes are far tougher than forge finishes, and even most commercial metal finishes. Certainly tougher than the pretty but fragile salt blued steel sold nowadays.If you start with bright metal, you can make your own rust blueing solution from nitric acid, chrome-free steel or iron filings, and water. Alternately, Pilkington rust blueing solution is good.A high-quality stainless steel carding brush is essential for beautiful results. Rust blueing is a skill worth having IMHO. It takes some trial and error, and is sometimes hard to do in a dry climate, but the results can be fantastic. Even a mediocre job, however, provide excellent rust prevention.StanOriginally Posted by Kees Heiden
Member
Forging scale is ferous oxide as far as I know, but it is a little hard to diagnose myself of course.
Nitric acid isn't really an over the counter chemical overhere. But when I find some time I will experiment a bit. Thanks for the ideas.
Guest
I have heard similar results can be obtained using high molar citric acid, but I have never tried it. I do know people that have failed miserably and damaged stuff using hydrochloric acid (battery acid). Any kind of chloride cannot be controlled. Muriatic acid is also said to work. The goal is to promote rust, but only very small crystals, not deep pitting. In fact, when done right, the rust becomes like a fine fuzz on the metal's surface prior to carding. When done wrong, pitting and splotches results.
Whatever chemical you use, the acidity in the resulting solution needs to be very very weak indeed. I don't know what household cleaners or industrial compounds contain nitric acid, but there should be some. I bought 3 liters of nitric acid a long time ago, before terrorism became an issue. Nitric acid can be used to manufacture explosives, so paranoid governments have made it and many other strong chemicals hard for the public to buy. If you or a friend have access to a chemical supply house, perhaps associated with work or a university chemistry department, you might be able to obtain some. Useful stuff.
Member
It seems like you can make controlled rust with a mixture of vinegar and hydrogen peroxide. But I don't know if that results in the desired kind of fine rust.
I have also experimented with an electrolysis process. A mixture of vinegar and table salt. The object on the anode, a piece of stainless steel on the kathode (or the other way around, I forgot). That gives a nice black color on the object which doesn't rub of. But I am a little bit afraid that the chloride ions from the table salt are a bad idea long term.
Guest
Acetic acid might work. Chlorine bonds with iron, and cannot be neutralized once it has attached to iron until it spends itself, resulting in large, coarse oxides and long-term deep pitting. Nitric acid is more volatile, and much more dangerous than salt or even chlorine, but when dilute, the corrosion process is quicker, and it makes smaller oxide crystals, and can be easily neutralized, and controlled.
Member
I had poor results from using just vinegar. It only formed a layer of black dust, easilly brushed off under the tap. It is the combination with hydrogen peroxide that makes it effective. But I haven't tested it myself and until I have tested it, I have little faith.
Contributor
In response to Stanley's wondering about household cleaners that contain nitric acid - I was playing around with various household chemicals to try and see what wood staining effects I could get (and then some metal pickling experiments) and found that some toilet bowl cleaners have nitric acid (between 5 and 10%) and also some dishwasher soap products (much lower, around 1%), so a toilet bowl cleaner MIGHT be a ready-made concentration for you.
Vinegar and Hydrogen Peroxide forms some Peracetic acid, which is highly corrosive, so that's probably why it works better. Even though it's a common food processing disinfectant, it's also pretty bad for you, so ventilate and use gloves. Of course, the same goes for using nitric acid.
By the way, neither did much for staining/ darkening wood (yes I know the vinegar and steel wool solution, I was looking for something more brown) and it was really hard to find products without dyes and horrendous fragrances added. Generic ones had the fewest additives.
Karl
Guest
Thanks. Toilet bowl cleaner might be just the trick.
As for making a stain, a very old stain used for both wood and cloth is made using nitric acid, water, and chrome-free steel wool. The dissolved iron penetrates wood well, and if you hit it with a propane torch, the iron oxidizes making a beautiful brownish red hue in maple. This wood dye or stain is unaffected by sunlight, making it ideal for gunstocks and knife handles. I have used it on boxes and casework with good results too.
If there is chrome in the steel (and most steel nowadays does have some chrome), the dye will have a greenish tint which is unattractive.
[OP]
Member
Thank so much for all tips... I will try Stanley tips but little afraid if i do something wrong.. There are some old used Ouchis Hiramachi with ebony handles that i will ry to restore as good as i can. Before i try better i show some photos so you guys see the condition of the chisels. Hope they are not i to bad shape.
Guest
The pics help, a lot. If the pitting is not too bad, a simple scrape down with a razor blade should suffice for cleanup.
Stan
[OP]
Member
So if i get it right, the cleaning procedure is as follow.
After i remove the handle i scrap carefully most rust from the flat surfaces. For the hollow and neck i need to use wet or dry sandpaper. Then clean up with some lacquer thinner.
As i understand the convertion of rust to magnetite is only needed to get the black color back to the chisel / Ura and get a good black finish before flattening and sharping. right?
I wonder, if you guys see the photos, is it possible to get those chisels almost back in the original finish?
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