[R-390] What is on the 390 chassis anyway

[Bob Camp]

Hi

The standard yellow aluminum coating is pretty tough. It will come off of edges of parts and areas that see significant scraping as modules are mated / un-mated. When we build parts that have that “stuff” on it, there is always a touchup bottle at the final inspection station. Even with careful handling, there will always be a corner here or there that gets the stuff rubbed off.

The main reason to have something on the aluminum is to take care of salt air / chlorine corrosion issues. If you live at the beach and use your radio while sipping Margaritas  out on the deck - worry about it. If you live in the middle of Kansas - worry about the tornados instead. 

Bob

On Oct 11, 2014, at 6:01 PM, Craig Heaton <hamfish at efn.org> wrote:

> Grayson,
> 
> "It comes off quite easy" Could it be nicotine??? I don't think the yellow
> coating Bob is speaking of comes off easy.
> 
> If it is nicotine, elbow grease and the cleaner of your choice. Mr Yuk frown
> here!
> 
> Craig,	
> 
> -----Original Message-----
> From: R-390 [mailto:r-390-bounces at mailman.qth.net] On Behalf Of Bob Camp
> Sent: Saturday, October 11, 2014 1:14 PM
> To: Grayson Evans
> Cc: R390A
> Subject: Re: [R-390] What is on the 390 chassis anyway
> 
> Hi
> 
> The yellowish coating on the aluminum goes by a number of trade names. You
> can buy a bottle of this or that and spread it on. The problem is that to
> really get it to stick you need to do a proper strip (as in chemical etch)
> of the entire piece and then re-coat the entire thing. By far the best way
> to do that is to take it over to a local plating shop and let them do the
> job.
> 
> Bob
> 
> On Oct 11, 2014, at 4:06 PM, Grayson Evans <wa4gvm at gmail.com> wrote:
> 
>> I am in the process of restoring one of my R390A's,  I disassembled it and
> disassembled the chassis.  I am trying to clean it up, and get the chassis
> back in reasonable shape.  In the process I have to do some scrubbing to get
> the dirt, old adhesive labels, and corrosion off the chassis pieces (sides,
> back, partitions, etc.), 
>> The chassis metal is coated with a light yellow something.  Is this an
> anodized coating or something the manufacturer sprays on?  It comes off
> quite easy, so I don't think it is an anodized coating.   Is it the same
> stuff thats on the solder connections?  
>> 
>> What would you recommend as the best (or reasonable) way to treat the
> metal in areas where the coating is removed?  just covering with a light
> machine oil?  Spray it with a clear acrylic?  
>> 
>> 
>> Grayson
>> TA2ZGE - Ankara, Turkey
>> KJ7UM
>> Follow the Hollow-State Design Blog
>> hollowstatedesign.tumblr.com
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
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