[Milsurplus] MFP Varnish Experiment

[Tom Dawson]

John,

It's www.sigma-aldrich.com

Product number 550795-5G for the 5 grams and 550795-1G if you want only a
gram (18 bucks for 1 gram).  They'll want to know what you want it for etc,
because, it is a chemical etc, but they sent mine DHL and it didn't take
more than a week.



regards,

Tom
WB3AKD

----- Original Message ----- 
From: "J Forster" <jfor at quik.com>
To: "Tom Dawson" <wb3akd at earthlink.net>; <milsurplus at mailman.qth.net>
Sent: Saturday, December 22, 2007 8:20 PM
Subject: Re: [Milsurplus] MFP Varnish Experiment


> Terrific work !!  Thanks very much. What's the URL of the chemical 
> supplier,
> please.
>
> -John
>
>
>
> Tom Dawson wrote:
>
>> Back in mid September or so some of the chaps here were discussing MFP
>> varnish, whether is was very toxic and what solvents wee appropriate for
>> removing it.
>>
>> This got me thinking as to how tough it would be to reproduce a suitable
>> varnish from "purchasable" stuff.
>>
>> The MIL Spec referred to, MIL-V-173, specifies a tung oil, phenolic 
>> varnish.
>> This sort of  varnish is much less common today than urethane spar 
>> varnish,
>> but I was able to find a product, "Waterlox Original" Marine Finish which 
>> is
>> a available online for about 33 bucks per quart that seemed to fill the
>> bill.  You can get it from Wood Carvers Supply Stores from
>> www.woodworker.com .
>>
>> By itself, the varnish looks OK although not quite yellow enough to pass 
>> for
>> the real thing.  Still, better than nothing.
>>
>> MIL-V-173 calls out oxine copper as the fungicide.  I don't know for 
>> certain
>> that this was the fungicide in the 40's but it looks to have been used in
>> the 60's.  I've seen copper sulphate solutions used for hoof-fungus 
>> (Thrush)
>> in horses, so a copper based fungicide makes sense.
>>
>> There are all kinds of different trade names for this substance but I 
>> found
>> a source for 8-Hydroxyquinoline, copper (ii) salt at one chemical 
>> supplier
>> (57 bucks for 5 grams) and bit the bullet to see how it would work.
>>
>> Mixed up 1 gram of the copper salt with 100 grams of the vanish, by 
>> weight,
>> because the spec called for 1% oxine copper.  100 grams of the varnish 
>> just
>> about fills up a small baby-food jar.
>>
>> Turns out to be pretty close to the color of the varnish on an old RA-20
>> that's been around here for 10 years or so.
>>
>> Given the prices of the varnish and the fungicide, this comes to about 18
>> bucks for 100 grams of home-brew MFP.  If the oxine copper doesn't make 
>> you
>> choke, the price just might.  The 80 bucks/quart does not sound so bad.
>>
>> The fungicide is not a hazmat, but you need to keep it out of the surface
>> and ground water as it is very toxic to fish.  Also, it is very 
>> irritating
>> to your lungs so you want to be sure not to inhale any of it.  (This
>> presumes that you're crazy enough to try this at home after hearing the
>> prices).
>>
>> The varnish is pretty thick, so if you want to spray it (use a mask) it
>> looks like mineral spirits is the stuff, or maybe xylene.  Mineral 
>> spirits
>> is first on the list of ingredients, and xylene is last.
>>
>> At any rate, it was a diverting experiment and I now have a hundred grams 
>> of
>> a fairly authentic MFP varnish that actually contains a fungicide, and is
>> not overly dangerous to work with.  If you're not planning on 
>> demonstrating
>> your Military Radios in the tropics, the Waterlox ought to be adequate by
>> itself, even if it is a little paler than the mix with fungicide.
>>
>> Happy Holidays.
>>
>> Tom
>> WB3AKD
>
>