[Milsurplus] MFP Varnish Experiment

[Bob Camp]

Hi

Most Tung Oil finish thins well with mineral spirits. A 1 part finish  
+ 1 part solvent mix is pretty common.

Bob


On Dec 22, 2007, at 7:45 PM, 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
>
>
>
>
> ______________________________________________________________
> Milsurplus mailing list
> Home: http://mailman.qth.net/mailman/listinfo/milsurplus
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Milsurplus at mailman.qth.net
>