[Milsurplus] Painting Aluminum - BC-348 in particular

[J. Forster]

Drano used to be Sodium or Potassium Hydroxide and some aluminum chips
mixed in. The hydroxide ate the aluminum and the reaction heated the mix.
There was an excess of Hydroxide to attack drain grease.

BTW, the reaction releases Hydrogen.

-John

================



> Gents:
>
>      The strong alkalis mentioned below reminded me:  When I was a Novice
> (back when you listened to radio via candle light), I read in 73 Mag (I
> think) about preparing aluminum for painting.  The suggestion was to soak
> the piece in a bath of Drano dissolved in hot water.  Obviously this had
> to
> be done outdoors.  I used the process on a project box for a 12 VDC power
> supply before I painted it with gray primer.  I still have the box/PS
> today
> and the surface is almost as good as new - just a few scratches from
> several
> moves through the years.  You might want to try the following on a scrap
> piece of aluminum -JIC.
>
>     I Googled <aluminum etching drano> and found a couple of sources that
> described a process similar to what I remembered.  But because this is
> some
> what hazardous material, you ought to decide for yourself if you want to
> take this approach.
>
>      Caveat Amateur.
>
>
> 73 de
> Gene Smar  AD3F
>
>
>
> ----- Original Message -----
> From: "J. Forster" <jfor at quik.com>
> To: <gl4d21a at juno.com>
> Cc: <milsurplus at mailman.qth.net>
> Sent: Thursday, May 13, 2010 11:23 PM
> Subject: Re: [Milsurplus] Painting Aluminum - BC-348 in particular
>
>
>>> Hutch:
>>>
>>> There are several problems with crackle paint on aluminum.  One is
>>> making
>>> it stick, and that is where zinc chromate primer came in.  Not sure it
>>> is
>>> still legal to sell, but it used to be available in spray cans, and
>>> normal
>>> can quantities.  The second problem is yours, incompatibility between
>>> primer and paint.
>>>
>>> The first problem is overcome with surface preparation, some sort of
>>> chemical bath which I have forgotten the details of.  Strong alkali, I
>>> think.
>>
>> Sodium or Potassium Hydroxide will etch the surface of aluminum to a
>> matte
>> finish, helping the paint adhere.
>>
>> -John
>>
>> ================
>>
>> The second is to use primer and paint from the same manufacturer
>>> and from the same product family, information which the manufacturer
>>> should publish.
>>>
>>> Google is your friend.  Or Bing if you swing that way.
>>>
>>> 73,
>>> George
>>> W5VPQ
>>>
>>> ---------- Original Message ----------
>>> From: John Hutchins <olegerityincj at austin.rr.com>
>>> To: Milsurplus at mailman.qth.net
>>> Subject: [Milsurplus] Painting Aluminum - BC-348 in particular
>>> Date: Thu, 13 May 2010 21:46:44 -0500
>>>
>>> Group  -
>>> Good evening -
>>>
>>> The black wrinkle tex paint I applied many years ago never cured it
>>> remained soft/slightly sticky.  So I am removing the bad paing job and
>>> starting over.
>>>
>>> That being said I noticed that there is a green chromate primer layer;
>>> Is this a paint or a immersion coating?
>>>
>>>
>>> Thanks
>>> Hutch
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>>
>>
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