Calling all chemists

Re: Calling all chemists

Kevin F, New Zealand

>That will work. Citric acid in the same concentration is good too, and may be easier to obtain.

Cheers

Kevin (PhD in chemistry)

Another answer from Oz

Bill Houghton, Sebastopol, CA

>Ron Fenton, who apparently lurks here, sent me the e-mail below, with permission to post it (Ron: GREAT information. You should step up to the table and post more often).

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I am a chemist (qualifications in metallurgy, PhD in Inorganic Chemistry and a retired University Lecturer) and have tried all known chemical methods for rust removal (electrolysis, phosphoric acid, salt/vinegar, EDTA etc)

I have been successfully using citric acid for rust removal from old tools for a number of years now. I took the idea from my grandmother who used to use citric acid (lemon juice) for removing rust stains from clothes. I have cleaned planes, saws, squares, bevel gauges etc. I am a hopeless collector of rust and seem to be always cleaning something since I retired.

The chemistry is fairly simple, the rust (iron oxide) is solublised by the acid (ammonium ion is also acidic) and the citrate ion coordinates to the iron ion formong soluble iron citrate.

How do you do it? I make a solution containing about 10% citric acid, obtained from the cake cooking stuff at the supermarket. Add a bit of alcohol (methylated spirits, ethanol, rubbing alcohol) it does not matter which it is only to break down surface tension and a squirt or two of detergent.

The article to be cleaned must be absolutely free from grease or it will not work. I use auto thinners or petroleum spirits depending on whether the item is painted etc.

Soak item for a few hours and give it a scrub with a green brilo pad under running water. Repeat as required. Some badly rusted items will need soaking overnight.

Advantages: enviromentally friendly, non-hazardous, non-toxic, does not affect paint japanning, plating etc. Soultion can be reused many times, just add some more citric acid.

Disadvantages: slower than electolysis (but much safer). Solution grows some biological slime on storage but I just strain it off.

The method can be used for things such as ebony/rose wood and brass squares etc without affecting the brass or wood.

I hope that this answers your question and if you have any further questions please contact me.

You can post the content of this email if you find it useful.

Regards,

Ron Fenton

Re: Another answer from Oz

Mike Lietzow

>Just some speculation from the non-inorganic chemist peanut gallery here. The addition of ammonium (NH4+) to the mix may be helpful as, after it donates its proton, the remaining ammonia (NH3) is reasonably volatile and may evaporate, helping to push the equilibrium toward a somewhat constant supply of protons.

Cheers,

Mike

Say Mike,

Todd O. Cronkhite Native of Maine

>Would you mind putting that into English for me?

Todd O.

Who's not a qualified chemist, but did do extensive research in alcohol in his younger years. ;~)

Re: Say Mike,

Mike Lietzow

>Well Todd, if we ever converge in Flooreeda or Maine, we can discuss it over a pint or 3 of Guinness. Then it will make purrfect sense. :-)

Cheers!

Mike

Sounds like a plan to me

Todd O. Cronkhite Native of Maine

>Heck, I'll even spring for the suds.

Todd O.

A few beers...

Don Thompson - Cutler Ridge, Florida

>... and you will not be worrying about proton donors at all!