# File Management



## RJSakowski (Jul 1, 2021)

I had a bucket of old files that had been sitting my barn for the past thirty years.  As I recall, they were purchased at an auction of a blacksmith shop.  They were well used at the time and had accumulated a generous coating of rust after a more than a quarter century of exposure to the elements and nesting birds.

Last week, I decided to take a shot at restoring them.  I started by cleaning off the loose crud and soaking them in EvapoRust for a couple of days.  That wasn't proceeding too well so I switched to electrolysis.  With the bulk of the rust removed, I wire brushed them ri remove any remaining.  It is important to remove as much of any loading of the file teeth as possible for the sharpening process to work well.  

The sharpening process consists of soaking in muriatic acid (HCl) which etches the surface of the steel. When acid etches a metal surface, it removes metal at a fairly constant rate regardless of contour.  As a result, a etching a rounded feature will effectively reduce the radius  and if carried long enough the radius becomes zero, resulting in a sharp edge.  The following illustration shows a section of a worn file (blue) and the result of the etching process (black).
	

		
			
		

		
	




For etching purposes, I made a container from 1-1/2" PVC pipe and an end cap.  This minimizes the volume of acid required. I used full strength acid (22%) which gives off obnoxious fumes so this is definitely a task to be done outdoors.  Etching time depends upon the condition of the file and on the size of the teeth.  Well worn files and/or larger teeth require more time. 

The files can be removed from time to time to check their condition.  To check, I rinse it in tap water, dry, and file a test piece of 1018. I am looking for a good bite with light to moderate filing pressure. If the file is sharp, I soak it in washing soda or baking soda solution to neutralize any residual acid, rinse with water, and dry thoroughly. At that point, the file is ready to use. 

I ran 33 files through the etching process.  One file was too far gone to restore it.  This was partially due to loading of the file teeth acting as a resist which essentially just etches the tops of the teeth, hence the necessity of cleaning any loading of the teeth before etching.  These files are all old American steel with the exception of a couple of German and Swiss files.  With new files running $6 and up and commercial resharpening running around $3 per file, this was a fairly lucrative project.


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## brino (Jul 1, 2021)

Great write-up @RJSakowski .

Thanks for sharing the details!

-brino


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## talvare (Jul 2, 2021)

Well, you obviously haven't watched this video 






Ted


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## hman (Jul 2, 2021)

Marc does have an interesting technique!


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## RJSakowski (Jul 2, 2021)

talvare said:


> Well, you obviously haven't watched this video
> 
> 
> 
> ...


No, I hadn't and it's a good thing too. Otherwise I would have three dozen files in the scrap heap rather than continuing to provide service.


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## ericc (Jul 2, 2021)

Do the renewed files work pretty well?  How much do you think they're worth compared to new files?


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## RJSakowski (Jul 2, 2021)

ericc said:


> Do the renewed files work pretty well?  How much do you think they're worth compared to new files?


They are not as good as new files, or I should say new prior to Chinese steel.  Also, any imperfections in the file such as gouges or missing teeth remain after sharpening.

Years ago, I used to buy Nicholson files at a local farm supply store.   Now they are not available anywhere locally. The last files that I bought were chain saw files, Swiss made.  They didn't cut well out of the box.


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## Mini Cooper S (Jul 3, 2021)

Be careful with muriatic acid!  One of our employees cleaned small area on the floor in our shop with deluded muriatic acid and the next morning we had a layer of rust over the entire table on a mill that was 20 feet from where he cleaned.  Fortumatly it cleaned up fine but those fumes are nasty!

Richard


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## brino (Jul 3, 2021)

I have learned to keep my small bottle of it out of the shop entirely.
It is double bagged inside a bucket with a tight fitting lid in the shed.

-brino


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## RJSakowski (Jul 3, 2021)

Mini Cooper S said:


> Be careful with muriatic acid!  One of our employees cleaned small area on the floor in our shop with deluded muriatic acid and the next morning we had a layer of rust over the entire table on a mill that was 20 feet from where he cleaned.  Fortumatly it cleaned up fine but those fumes are nasty!
> 
> Richard


I have a 1 gallon plastic bottle of muriatic acid which lives in my basement where my shop is located.  In more than forty years,I haven't had a rusting problem with my machines or tools. I keep the bottle tightly closed. If an open container  is present, HCl fumes do escape. If HCl fumes are suspected, an open container of ammonia will quickly show them.  The two combine to form NH4Cl, a dense white fog that settles on everything as a white dust. Applying even diluted HCL to a surface like a floor is another thing.  It will all eventually dissipate as vapor and react with any metal surface.

HCl fumes are also dangerous to the respiratory system.  Fortunately, exposure results in a severe cough which usually makes one take corrective action..

I worked as an analytical chemist for six years where we literally boiled away a half gallon of HCl each day.The procedure was carried out in a fume hood but with that amount of acid, some fumes made it out into the lab.   

As with all chemicals, they need to be used with some knowledge and respect rather than fear.  Proper PPE, understanding the chemistry, and  and knowing what to do in the event of accident is paramount.


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## matthewsx (Jul 3, 2021)

I work in IT so when I saw the title of this thread my mind went somewhere else entirely....

I have some older files I may try this with, thanks for the info.

John


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## NC Rick (Jul 3, 2021)

talvare said:


> Well, you obviously haven't watched this video
> 
> 
> 
> ...


I love that guy!  I would enjoy spending time with him and I tremendously respect what he says.  I hope he is well as I have not seen new videos in a long time.


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## NC Rick (Jul 3, 2021)

RJSakowski said:


> I have a 1 gallon plastic bottle of muriatic acid which lives in my basement where my shop is located.  In more than forty years,I haven't had a rusting problem with my machines or tools. I keep the bottle tightly closed. If an open container  is present, HCl fumes do escape. If HCl fumes are suspected, an open container of ammonia will quickly show them.  The two combine to form NH4Cl, a dense white fog that settles on everything as a white dust. Applying even diluted HCL to a surface like a floor is another thing.  It will all eventually dissipate as vapor and react with any metal surface.
> 
> HCl fumes are also dangerous to the respiratory system.  Fortunately, exposure results in a severe cough which usually makes one take corrective action..
> 
> ...


Some years ago, a friend went into his basement with HCI to clean up and etch a sump well.  He never came out of there alive.  For sure, respect that stuff.


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