To me the best and safest way bar none remains Evaporust. Safe, will not remove metal only the rust, which means, objects can be left soaking longer if you forget without hurting them. Safe for the environment, septic tanks, your bare hands etc. Re-usable, just filtered it and re-use. That helps mitigate the cost of the product. I buy it by the 4 gallons.
But more importantly, it works and does it safely. The only other method which works as well, in my book, is electrolysis. Works great but require a power source, I used a 12 V battery charger, must be used with plenty of ventilation since the by product is the release of hydrogen gas, which can get a tad dangerous.... The anode is consumed in the process, you can get by using Stainless steel for long lasting anode, but doing so release more toxic gas, so I would not advise that. But my biggest concerns with it is what it does to the object. Possible Hydrogen embrittlement, which can be restored by tempering the object afterward. And you are left with a toxic mess to dispose (not in your sewer or septic).
So Evaporust it is for me. I go thru a few gallons a year :-)
As with any rust removal process, scrubbing the loose rust away and degreasing/degunking the object before, helps getting it to work faster and better. It also keep your precious solution cleaner.
I usually use Krud Kutter for that and a stiff brush.
The beauty of using chemical chelation to de-rust an object is that you do not abrade metal away (like sanding etc). Hence you do not run the risk of erasing some markings. To me its like the results of a good electrolysis job but without all the hassles and dangers. Museums have been reportly used electrolysis to derust their objects.
With Jean's stuff came a few tools, one was a roll of brace bits. Unfortunately, inside one large pocket was a few bits which were soaking wet for a while, really did a number to those poor bits.
The bit roll
Some were plated and remained mostly intact, others not so much.
That center bit still has the perfect geometry
A fresh batch of Evaporust, clear yellow
After 22 bits, 2 planes iron and a metal plane body and parts, its starting to get brown.
Perhaps the biggest negative about this method is finding suitable containers
to handle the size of the object without wasting too much precious liquid.
This was left overnite, and was rotated once in a while
since the flutes are slightly sticking out of the bath
In the end your object will take a dark blackish color cause by the top layer of loose gunk.
After I'm satisfied, it has worked enough, I'll scrubbed them with the green scrubby, rinse and left with a dull darker grey.
Off its bath in Evaporust, pretty blackish.
The dirtier your liquid, the blacker it will come out.
Yes, sharp eyes readers, I need a new scrubby :-)
Then off to the wire wheel we go. I use a soft bristle steel wheel, being soft, I wear them out fast and go thru a few. Mind you, if you only saw my pile of tools, you'll understand why :-)
If you ever wire wheel a rusty object without treating the rust first, you probably ended up with a shiny dark brown surface. In this case, after Evaporust, we go from dull grey to a bare metal shine. Sometimes the bits take an almost aluminum looks, which I don't care for, but leave it alone and it will darken back. I guess the various colours (shades of grey) depends on the metal composition. The tell tale demarcation between the steel tip forged welded to a softer iron body becomes visible, due to the colour differences.
Earlier I did a quick test to see the various stages.
Only the nose section was dipped in Evaporust
(for lack of suitable container :-)
then wire brushed
The stem was simply wire brushed, no Evaporust first.
It removed surface rust but gave the object a shiny brown appearance
Between these two pics, you can see the transition from
Evaporust untouched (dull grey) to the right and shinier after wire wheel.
You can also see how it has exposed all the pitting that took place under the rust.
Here is a Canadian Champion chisel that got dunk in between (seens in first pic of soaking, in my last blog)
Note the severity of the pitting.
No pitting were it matters the most. The back will get flattened first
and I expect it will take out lots of the small pitting.
The trademark became clearly visible
Back to our boring bits...
All the bits have been processed, only need some touch up sharpening
before being put to good use. Bottom one has been de-rusted as well now.
The two on the far right have been rejected as being too much pitted.
In this case, you can see the flutes sticking out. If left alone you will be left with a tell tale demarcation line almost impossible to erase. My solution? Simply rotate the object once in a while.
Either that or find a more suitable container, or add more liquid.
Evaporust will not harm paint finish, or japanning, but if there was rust under, it will lift the paint in those areas. Similarly how it will react with plating, if its solid, no harm, rust under, flake off.
I try to avoid wood contact, because wood and liquid don't play nice.
In this case, I kept rotating the chisel as well.
A small block plane. Note the unharmed paint finish
I always thought these blue and red planes were German,
but this one has a blade clearly stamped Japan. The sole and sides are also plated.
Bit on left is OK, the remainder two, need more soaking.
Last on right was later rejected as too much pitting took place.
After its first wire wheel, put back into soaking, there was still rust visible.
BTW That bit has a patented strange nose.
It looks like a Jennings for the first few twist then change into a Irwin center bit???
The patent date 23 Oct 1900 (?) must fall on a Tues if US (since 1848 I believe?)
if not its either a typo (it happened in the past more often than you may think)
or I read it wrong or Its not a US Patent?? Work in progress
Any drilling bits can benefit greatly from being rust free and shiny, to help the shavings flow out.
In addition those that have a threaded nose to advance the bit, are often impaired by too much rust and cruds in the threads. Using a file to recut threads is risky at best, you can create more problems than you solved. Soaking in Evaporust then wire wheel the bit with a soft wire brush, get those pesky threads clean up effortlessly. The bits could benefit further from a quick buffing on the flutes to help those shavings flow easier, but in my case I never got around to do that and they works just fine.
Lastly, after this chelation process we have exposed fresh metal which can quickly start to rust if left alone.
Drying the object after its water rinse, then wire wheel, and finally wiped with a coat of WD 40 and/or a wipe with Autosol will help keep it rust free. Your results may very well vary with your geographic location, but flash rust can happen quickly if left alone. Especially vulnerable are all those small craters left behind by the pitting that took place before hand. You can sand them out, depending on location, but on drilling bits you have to be careful not to end up tapering toward the nose, making it sure to jam quickly while drilling. The outside section (often the most pitted) only keep the bit centered, and has no effect on the cutting action. It is the inside of the flutes, where the shavings glide thru that matters. The smoother the better chips ejection, the deeper you can go before jamming by choking. Easily buffed using a shoe shine buffing action by hands, using a long narrow piece of clothe (or whatever). The idea is to polish, not sand
This mean, avoid the urge to sand the outside pits, and instead, wax your bits. That will fill in the pores (pits) of the metal affording better protection against rust and it will turn easier, Bonus! :-)
Bits are only to be sharpened from the inside faces. Please learn and understand the bit cutting geometry before attempting to file them sharp. If you do not know what you are doing you can quickly ruin a bit, some times mortally :-(
Bob, with a never ending pile awaiting its dip in Evaporust
Full disclosure, not paid or rewarded or whatever by Evaporust to hawk their products, I am just a satisfied customer, that's all folks.