File Renovation

Hello again,

"Files are cheap these days". Well they may be cheap, but I have had no success with cheap files, they seem to be worn out within hours of unpacking them. I only buy good files and they are damn expensive!

My experiment with a file in the phosphoric acid at ambient temperature was interesting. After 3 days things seemed to be going well and the file was very noticeably sharper than it was.

The morning of the 4th day was a disaster. The liquid had turned a milky blackish colour. On taking out the file, it was covered with a whitish green substance. Allowing it to dry out showed the typical greenish hue of weathered copper. The file was very blunt, although this may well have been because of the thick deposit on the file.

Any chemist here who can say what is going on here? The change overnight was from a clear solution of phosphoric acid with some black particles on the bottom, perhaps coving 30% of the base. In the morning there was only this milky solution tinged black.

Andrew.

Hi

Not being a fan of using Acid around my person and the dangers involved can I suggest and safer way.

Use Electrolysys Method setup article at

http://antique-engines.com/electrol.asp

Clean and remove rust oil and swarf from the teeth with the files connected to the NEGATIVE terminal until clean

Then Connect the files To the POSITIVE terminal then monitor the progress until you have a file that is again usable

PS can someone instruct me how to setup the "LINK" function on this forum

Eric

Hello Eric,

I too do not much like acid about the place. however Phosphoric acid does not have the effect of the other common acids. I am quite happy to fish out files from solution with my hands, provided it is not too hot. It does go for concrete though.

I will give your electrolytic method a try when I have any more blunt files. All of mine are now sharp!

What is the working solution for the electrolytic solution?

Regards,

Andrew.

Hi Andrew

The mix ratio is not very critical as around 5 gallons water to 1/3 to 1/2 cup laundry soda as a guide line seems fine.

Adding extra washing soda will not make it work any quicker.

The higher the current it will make it work quicker and raise the temperature of the solution and produce more hydrogen gas so good ventilation is essential.

No Stainless Steel electrodes thanks the break down into the solution so mild steel is ideal.

Eric

Write some text for the link and highlight it.

Click the 'chain and planet' link icon and insert your link.

Neil

The link Eric provided suggests a cup full of Sodium Carbonate (Washing Soda) to 5 gallons of water, ie a weak solution.

However, I recommend carefully reading the safety information before trying it. For different reasons the method is every bit as dangerous as using Sulphuric Acid, perhaps more so. It involves:

• a strong alkali (read the instructions)
• mains electricity and a bath full of electrolyte. (lethal shock hazard)
• a car battery charger or computer power supply used in a way not intended by the manufacturer (may cause a fault)
• a process that can make a toxic solution from stainless steel (Chromates)
• the production of explosive gases (requires good ventilation)

Don't let me put you off, I've seen the process demonstrated on TV and it works very well. Just take care. In particular don't let anybody near it whilst power is connected.

Dave

Hi Neil

Thanks for the info and apologies to Andrew for the Hijack

http://antique-engines.com/electrol.asp

Eric