contact spray ingredient(s)

Something of this sort is still available. It used to be called by the brand name of Cramolin (I believe this was made in Germany), and the Caig Laboratories company now makes a similar product under the brand name of DeOxIt.

The MSDS (Material Safety Data Sheets) I've looked at for the Caig products are somewhat unrevealing. The active ingredients are proprietary / trade secret and are not specifically described.

According to one USENET posting I've seen in rec.antiques.radio+phono, it is possible that one of the active ingredients is oleic acid. "As to the anti-oxidant qualities of Oleic acid, it has been used for years in metal-finishing as a cleaner. It is the active ingredient in well-known brass-clock cleaning compounds (though "tempered" with acetone), and in several other similar applications."

Another posting states that

As Peter pointed out (which I had forgotten), oleic acid is the main ingredient in clock-cleaning formulas that have been in use for a very long time. Since acetone doesn't dissolve oxides, that pretty much leaves the oleic acid as the active ingredient.

I've been curious for years about Cramolin's (DeOxit's) composition. The MSDS doesn't list it, but somewhere years ago I read that it was oleic acid. And I found a 1930 trademark registration for the original German product, under the name Gramolin, described as a treatment for motor commutators. It's not much of a stretch to get "Gramolin" from "Gramme" (DC machines were sometimes referred to as Gramme machines) and "olin" from "olein," some of the derivatives of oleic acid.

gives a description of oleic acid, and mentions that in the (impure) form in which it's often manufactured it's a dark, reddish-yellow or brownish-red oil. Once fully purified it's colorless.

So, it would not be surprising if the sprays to which you are referring are a mixture of somewhat-purified oleic acid, with solvents (e.g. various alcohols) and propellants (propane and/or carbon dioxide).

--
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And, as a followup... it looks as if it wouldn't be difficult or expensive to experiment with this stuff to see if it's the real thing. After a few minutes of searching on Google I see one supplier selling oleic acid for under $14/gallon (purity not stated), and another selling laboratory-grade for $24 per pint or $95 per gallon.

One could make a lot of contact cleaner with a gallon of this stuff :-)

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Dave Platt                                    AE6EO
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  I do _not_ wish to receive unsolicited commercial email, and I will
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And do a lot of damage to parts if the mix is wrong. There have been a number of cheap knockoff contact cleaners that damaged plastics, washed away the carbon track on pots and caused arcing in switches.

--
Former professional electron wrangler.

Michael A. Terrell
Central Florida

Some of the stuff I bought is labeled residue free and I found that it doesn't leave any residue. I think it's made by CAIG Labs.

This is a lot of information and pointers! A liquid organic acid that comes in different shades of orange, red, and brown fits my observations and memories, and makes a lot sense besides.

According to my chemistry references, oleic acid, C18O2H34, has a linear carbon chain of 18 atoms with one double bond in the very middle and a COOH group at one end. No wonder it looked oily with that chain length.

The Cramolin brand name nowadays seems to apply to a whole number cleaning agents (solvents, detergents, lubricants), only one of them being "Cramolin Contaclean" (this too is formulated as a spray, I saw no other). The German MSDS (Sicherheitsdatenblatt) of "Cramolin Contaclean" doesn't disclose any active ingredient(s) either. The solvents are unremarkable: dimethyl-propyl-methane and 2-propanol. The propellant is CO2. They also state a solvent content of 84.3% and a solid content of 6.5%.

The other day I had a spray can of "Kontakt 60" (which appears to be the major brand of this kind of thing in Germany) that had started to leak at the bottom seal. This also left a residue: a solidified puddle of sticky brown goo that still allowed the bottle to be removed from the shelf with moderate force. So either oleic acid polymerizes to some extent (after all it does have a double bond) or there is some other ingredient in addition. Anyway, the goo might help to contain the oxide residues and keep them out of a contact's way. The goo did readily dissolve in alcohol (i.e. ethanol).

I emptied the remaining contents of the can into a bottle and the color of "Kontakt 60" turned out a much diluted wine red.

Martin.

clicliclic wrote (in ) about 'contact spray ingredient(s)', on Fri, 15 Apr 2005:

I think it oxidizes rather than polymerizes. It's a derivative of a 'semi-drying oil', although not a very marked one.

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Thanks for pointing out the possible relation with the drying of linseed oil (used for oil paints and as varnish) and similar oils. However, although (semi-)drying oils harden through oxidization, the actual mechanism is polymerization through the addition of -O-O- oxygen bridges between formerly doubly bound atoms on different carbon chains.

Linseed oil is essentially an ester of glycerine with linoleic acid (C18O2H32) and linolenic acid (C18O2H30), which differ from oleic acid (the suspected contact spray agent) by possessing two and three double bonds, respectively, rather than just one. Oleic acid should therefore be much harder to (oxidize and) polymerize.

I am no chemist, and all this is taken from my reference on organic chemistry!

Martin.

clicliclic wrote (in ) about 'contact spray ingredient(s)', on Sat, 16 Apr 2005:

Yes, oxidation comes first, and it IS slow. So polymerization is even slower.

You're doing OK so far.

--
Regards, John Woodgate, OOO - Own Opinions Only.
There are two sides to every question, except
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk