[Hallicrafters] Re: Chassis coating

[Roger K8RI]

> At 11:09 PM 6/15/2005, Roger K8RI wrote:
>>Now all I have to do is figure out the mix for making an alodine solution.
>
>
> Click below.
> You will get eighteen thousand six hundred hits.
>
> <http://www.google.com/search?hl=en&q=alodine&btnG=Google+Search>
>
> The first link I got is:
> <http://www.eaa1000.av.org/technicl/corrosion/alodine.htm>
> and contains lots of information. After reading this, I would not do this 
> at home.

For some strange reason I never thought to look for Alodine here and I'm a 
pilot who is also building an airplane. I just didn't associate this with 
airplanes. That and the one I'm building is fiberglass.

I used to do silver plating using a mix of silver cyanide and potassium 
cyanide so I'm not at all concerned about working with chromic acid and the 
associated chemicals.

I would add that it is not necessary to completely dip a part and portions 
of a part can be done.
There is also a "one step" system which is very easy to use, but also 
expensive.    OTOH you use far less chemicals with no need for tanks, easy 
clean up, and the disposal problem is much less.

I've never seen it used on a chassis, but I have seen it used on airplanes 
and it's much like using a "Magic Marker"(TM) with a bit of scrubing.

Another one of those brief stories:
As I said, I used to do a fair amount of silver plating.

The chemicals and current determine what the surface looks like when 
finished.

You can do plating using an silver nitrate solution with a bit of Nitric 
Acid.  I don't remember the mix now, but "I think" it was about 10% acid by 
volume.  As I recall this is the one that will flash plate copper with a 
thin layer of silver.  However, electroplating with this solution produces a 
surface that is very rough and looks like a bunch of crystals stuck 
together.

For electroplating you use a mix of potassium and silver cyanides.  This is 
the stuff you keep well away from acid as that causes a reaction releasing 
cyanide gas.

I did the work in a "fume hood" and as this was a regular process the system 
was kept "set up" and ready to run.  Current was from a small battery 
charger.

One day, they had a safety inspection and somebody, not familiar with the 
process, didn't like the looks of the *stuff* even though the room was kept 
locked and the hood labled as well as the chemicals and the pails as to 
their contents..

One of my co-workers said he'd take care of the stuff for them and just 
dumped it all together.  Yup! About half a pail of silver nitrate and acid 
into half a pail of potassium and silver cyanides.  He remarked later, "Boy 
that stuff sure boiled up and fumed and smoked like it was hot".  I don't 
think he ever realized how lucky he was.  Just one whif of that gas could 
have been fatal.  OTOH he was reminded about how many thousands of dollars 
that system had been worth.  I didn't ask what he did with the stuff after 
mixing it.  Still  it required a hazmat team to clear the room and declare 
it free from toxic gas.  That and having to evacuate about 20 workers from 
the adjacent area served as a reminder to not just dump things togeher until 
he knew what they were and what they would do.

Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
www.rogerhalstead.com



>
> Roy
>
> - Roy Morgan, K1LKY since 1959 - Keep 'em Glowing!
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>
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