Rusty blade cleaning?

[ugly]

I have an angle grinder, don't want to spend any cash and don't want to spend hours on the job.

I was more after a "don't do that, or you'll knack it", but since no one has warned me...

Wire wheel if you must but better to use wire wool.

 

[HE117]

I use a number of derusting techniques that depend on what is rusted, and how much..

1. If you have what I call "sugar rust" where the rusting is deep and has started to de-laminate, you have lost metal which cannot be replaced.. you need to get to the bottom of the pitting and remove the rust layers above, otherwise the process will just keep going. Rust is auto catalytic in that the rust will cause more rust to form. How you attack the sugar rust is down to what surface you want to end up with or how much of the original surface you want to recover. You may need to revert to quite destructive processes to remove the scale, I tend to use a fine file or a fibreglass brush which is reasonably controllable.
2. I still have carbon steel kitchen knives and pocket knives as you can get a decent edge on them, however they do stain. I have a small pot at the side of the kitchen sink with an old wine cork in it. I used to use Vim or one of the old scouring powders, but now I have a blob of "Astonish" pot cleaner in the bottom of the pot. You just get some on the end of the wine cork, lay the stained blade flat on the side of the sink and rub it with the end of the cork. It brings it up clean in seconds.. a quick run under the tap and dry with the dishcloth... done!
3. Things with a metal finish like bluing on guns that have rust spots can be treated with fine oil and 0000 wire wool. You can't get it in most shops.. I get it from the internet! It will remove surface rust without touching the finish. Do not try using anything like Scotchbrite on these surfaces, even the softest grades will strip it off..
4. Old blued surfaces will go a sort of chocolate brown over time.,, This is caused by the oxidation of the blue ferric oxide to red ferrous oxide. You can reverse this by boiling it in plain water for half an hour or so...

Be very careful of dunking stuff in chemicals, both proprietary cleaners and the likes of vinegar or molasses. Some of these can have very long term destructive effects on certain materials. Most of the "Instant restoration" vids on Youtube are moronic. Good restoration takes time and research if you are not going to do more damage than you started out with. Make sure you know what it is you are dealing with before you start..

Once you have restored whatever it is you have de-rusted, than perhaps you might consider trying to stop it rusting again.. A coat of wax polish will provide protection.. I use Renaissance wax, which is specifically designed for conserving both wood and metal...

 

[ugly]

Once you have restored whatever it is you have de-rusted, than perhaps you might consider trying to stop it rusting again.. A coat of wax polish will provide protection.. I use Renaissance wax, which is specifically designed for conserving both wood and metal...

I started reading your post and the same thought popped into my mind!

 

[CrabfatBILL]

Sit outside and repeatedly stab the lawn. When rust free, clean up and sharpen.
CFB

 

[Lardbeast]

On a separate, but related note, I have a working kukuri that is lightly rusted, but with some notches in the edge through use/misuse.

I'm assuming it's a bit much to try and sharpen these out by hand. What would happen if I used a grinder and some oil?

Not after a shiny finish, since it's a working knife, just a sharp edge and de-rust.

Do it by hand. Start with a fairly coarse stone to remove the nasty bits. It takes a bit of time but you can save the edge doing it that way. Work your way to finer grits as you clean it up. Don't drag the blade backwards along the stone as that rolls the edge. Get the angle right, use a good honing oil and move forward into the blade in a slicing motion from the guard to the tip.

 

[HE117]

Sit outside and repeatedly stab the lawn. When rust free, clean up and sharpen.
CFB

yeah... but you run the risk of bending the tip on stones etc, and of ruining whatever edge you had on the knife.. OK for agricultural stuff but I would not do this with anything but the crudest of blades..

A good tip for cleaning garden tools is a bucket full of oiled sharp sand.. just stab the tools into the sand... it will clean and oil them in one go...

 

[Truxx]

Autosol

That's AUTOSOL, not anything else that may sound similar.
Don't excessively 'spot clean' the rusty bits, you need to clean the whole blade equally otherwise the rusty bits will end up with a different optical quality.
If you have a roll of rifle cleaning cloth, that's ideal for polishing the blade with the Autosol.

Autosol applied with a piece of cardboard.

 

[Lardbeast]

Go pick up a whetstone from a car boot sale. Have a look at the video below. It seems the difference between straight and curved blades is that for the latter you move the edge of the blade in the shape of the curve to maintain and even edge.

Disagree with going backwards on the stone. It actually makes my skin crawl as it rolls the edge.

 

[HE117]

I started reading your post and the same thought popped into my mind!

Great minds etc...!

 

[Lardbeast]

I have an angle grinder, don't want to spend any cash and don't want to spend hours on the job.

I was more after a "don't do that, or you'll knack it", but since no one has warned me...

Don't use the grinder, you'll knack it. If it's an original old kukri, it could have some value to a collector.

 

[HE117]

I'm commenting to follow this thread, but also because I have a Kukri that belonged to my great grandad (I think) that needs restoring.

@vvaannmmaann do you have any photos?

I was given No2 son's Kukri to fettle when he came back from tour.. I think he had been hammering in nails with it..

They are actually made from quite soft metal, so you need to be a bit careful if you try to attack one with machine tools etc.. I used a polished hammer to beat out the dents and straighten the tip and then used a fine file to get out the nicks and reshape the blade.. (Don't use a Kukri for cutting D10.. it has hardened steel wires in it!). Clamp the Kukri in a padded vice if you have one.. it makes things a lot easier if you do. Follow on with emery paper (with a backing block!) in finer grades until you get the surface you want... Polish with Solvol on a wine cork if you are looking for a "Parade Gloss".

Kukris are working knives and have a lot of metal in the blades, so you can afford to be quite brutal with them.. that said, be careful with the end of the pommel, which can easily get chipped or broken.. it is the weakest part of the design. If you watch how the Gurka wives use them for cutting up stuff, they generally prop them tip down and push the meat down the blade from the handle end...

Again, make sure you wax or grease the blade before putting it away.. Vaseline is good and not as smelly as goat fat..

 

[Tappet]

Don't use the grinder, you'll knack it. If it's an original old kukri, it could have some value to a collector.

No idea; I'll take some pictures at lunch

 

[Oyibo]

Don't use the grinder, you'll knack it. If it's an original old kukri, it could have some value to a collector.

There's kukris, and there's kukris. I have 1 x dress kukri (chrome plated) that I would not let near a sharpening stone of any sort. The other two are very utilitarian, and keep a very good edge, but they have been abused a bit. I wouldn't have any qualms about taking the latter two to a bench grinder if there are really big nicks out of the blade, but I would take it very gently so as not to lose the temper (of the metal, not mine).

 

[Bacongrills]

Sit outside and repeatedly stab the lawn. When rust free, clean up and sharpen.
CFB

That won't look like you have gone mental at all.

 

[kelvin_273]

Sit outside and repeatedly stab the lawn. When rust free, clean up and sharpen.
CFB

It's a knife not a gas plug.

 

[Tappet]

There's kukris, and there's kukris. I have 1 x dress kukri (chrome plated) that I would not let near a sharpening stone of any sort. The other two are very utilitarian, and keep a very good edge, but they have been abused a bit. I wouldn't have any qualms about taking the latter two to a bench grinder if there are really big nicks out of the blade, but I would take it very gently so as not to lose the temper (of the metal, not mine).

Mine is in clip:

 

[Bacongrills]

Citric acid for derusting.
No contest.

 

[Oyibo]

Mine is in clip:

View attachment 504649View attachment 504646View attachment 504647View attachment 504648

Looks like there's been a bit of clumsy grinding on the blade. Might be a need for a wire brush, and then heavy duty polishing compound using a bench grinder (with wire brush and polishing wheel).

Here's one of my utilitarian ones (I haven't cleaned it for some time). I've only ever used wire wool on the main part of the blade, and it comes up well, although the photos don't show it. The blade is a double grind to answer someone's earlier question:

This one is Pakistani. It holds a very good edge.

As suggested earlier, might be worth getting someone who knows what they're talking about (not me) to advise you.

 

[Blogg]

Citric acid for derusting.
No contest.View attachment 504635
View attachment 504657

Or Oxalic Acid, which is stronger (so read the safety stuff and use PPE!) and in lower concentrations can be used to treat rust stains on stone, brick, wood, leather, clothing etc.

Turns rust into a water soluble ferrioxolate salt which handily is white-ish, not an 'orrible brown red.

 

[Bacongrills]

That's the main benefit of citric acid, its totally safe, non toxic, non polluting and you need no PPE.

Plus it works just as good as anything else, even electrolysis.