[Milsurplus] Water, Water Everywhere.

Fri Dec 11 22:09:45 EST 2015

I have very successfully reclaimed distributer and magneto caps by 
carving out any carbon tracks that can be found, washing them with 
detergent,rinsing and baking. If the item is pure bakelite or bakelite 
and metal, heat it to about 250 degrees F in an oven for a couple hours. 
Take it out of the oven hot, and smear silicon grease all over it, then 
put it back in for a couple more hours, turn off the heat and let it 
cool. This process completely ended all hard starting problems I had 
with a  vehicle on cold damp mornings. I have also done it at about 150 
degrees to fibre insulators on IF and RF transformers with good results. 
However, moisture is not always the problem. I have had fibre insulators 
and boards in old radios and TVs that became leaky at RF, but tested 
fine on DC. Replacing them with plastic gave unreal improvements in 
performance even though fabricating a replacement was challenging. I 
tried baking them, it didn't change anything. I think the chemistry in 
the fibre and/or varnish changes with time and becomes conductive. I 
wonder if this has anything to do with the  belief that a "Q" model 
BC-348 is the best?

   Bruce Gentry, KA2IVY

On 12/11/15 7:50 PM, John Hutchins wrote:
> David/Bob - All-
>   The dry out box could be made from HVAC fiber glass board and 
> aluminum Tape with  heat lamp.
> If you could get the lamp on the bottom and have and  oven rack to let 
> the heat circulate.  you may be able to get an oven rack from a used 
> /junk appliance store.  The fiberglass Board from Homedepot?
>
> As you say meed to seal the Bakelite how about a couple coats of varnish?
>
> My Thoughts
> Hutch
>
> On 12/11/2015 11:06 AM, Bob Camp wrote:
>> Hi
>>
>> Before you start, consider that there may be a layer of dirt involved 
>> in the process.
>> The time to get rid of that is *before* the dry out. The usual 
>> cautions apply to using
>> solvents to do this.
>>
>> Winter is a good time to do a dry out process. All you really need to 
>> do is
>> get the humidity down low and keep it there for quite a while. You 
>> can accelerate
>> things with a lot of heat. That may or may not damage other stuff in 
>> the gear. More
>> or less:
>>
>> Rig a hot box, heat it with what ever you have
>> Monitor the temperature with something simple
>> Keep some air flowing inside the box with a small fan
>> Control the air exchange with the outside so there is *some* exchange
>> For added fun monitor the humidity. (or look at the humidity outdoors 
>> and
>> do the delta T math).
>>
>> The goal would be 0% RH (which is impossible). Anything below 5% is 
>> likely to be
>> “good enough"
>>
>> Once you get the humidity out, you need to keep it from getting back 
>> in. The issue
>> is that whatever was doing that probably has degraded in the last 50 
>> to 100 years (haven’t we
>> all …). There are an enormous number of candidates for this. Many of 
>> them can create
>> as much trouble as they fix. For solid parts, low viscosity / long 
>> setting time epoxy
>> might be your best bet. For delicate little stuff, something like 
>> silicon (synthetic) oil
>> may be about the only viable approach. As always, proceed carefully. 
>> You very much
>> do *not* want to toss this stuff in there and find it dissolves the 
>> part(s). There have been
>> so many materials used over the years that there is no 100% safe 
>> thing to use. If oil
>> and epoxy are out, then stuff like wax is your next choice. In a hot 
>> part of a radio, they may not
>> do really well. In a room temperature part of the gear, they work 
>> quite well.
>>
>> It’s also quite acceptable to skip the displacement step. You may 
>> find that your dry out
>> process needs to be repeated in a few years.
>>
>> Bob
>>
>>
>>> On Dec 11, 2015, at 11:43 AM, David Stinson <arc5 at ix.netcom.com> wrote:
>>>
>>> Many of our beloved old radios have been sitting, cold
>>> and quiet for many decades.  Some of them getting close to a century.
>>> Recently, I've been dealing with bakelite and phenolic
>>> in our sets which have taken-up moisture over the years. Right now 
>>> on the bench I have a TCS
>>> receiver in which one of the pins of Z202, an IF transformer, is 
>>> leaking B+ to ground through
>>> the phenolic.  Pulling an IF from a TCS is a pain
>>> but do-able.  So may we discuss ways to gently drive moisture
>>> from our sets?  I can "get rough" in the stove with
>>> those bakelite inserts in WWII radio connectors but
>>> that won't do for a whole set.  I've tried powering just the 
>>> filaments and leaving a set for a couple of days but I don't think 
>>> they get hot enough to do much
>>> good.  Heat lamps can do some damage.
>>> What have you done?    I'm thinking of light bulbs
>>> with the radio in a thick cardboard box, *outside* in case the box 
>>> decides to catch fire or something.
>>>
>>> 73 Dave AB5S
>>>
>>>
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