Message-ID: <3A5AEACE.FB9B17B4@sitestar.net>
Date: Tue, 09 Jan 2001 05:41:18 -0500
From: "Rye Gewalt" <ryeg@sitestar.net>
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To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Bonfires (and wet wood)
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I seem to recall that the old timers (I'm one myself
now) used to boil dry
wood in paraffin to make insulators for open wire
feeders.  I think this
makes sense.   But, of course, if it did catch fire I
would burn really
well.   Just a thought....

As a sail boat owner, I know how easily water can get
under varnish and 
never leave -- while the wood discolors and rots.  If
one were to varnish
wood that's going to be exposed to the outdoors, a
marine varnish might
make good sense as it has ultraviolet inhibitors to
keep the sun from 
eating it up.  I use a marine varnish called Sikkens
(?) from Europe
that really stands up to the weather.

Rye Gewalt K9LCJ
Springfield, Virginia


James Moritz wrote:

> Dear Dave, LF Group,
>
> Sorry to hear about G3YXM's slight overheating problem. This type
> of thing is certainly a hazard with LF - I expect most people have
> their tales to tell. It is one reason why I don't leave my station
> running in beacon mode while I sleep; it is also a good reason for
> having the loading coil located away from the house.
>
> I have found that the biggest problem comes from damp timber. If in
> a high voltage field, the losses are rather high, so it gets hot. Little
> white arcs form on the surface of the wood, and wander around in
> a fascinating way, leaving charred trails, and setting fire to things.
> It is very impressive at night. Paradoxically, dry wood seems to be
> much less prone to this. During the summer, I made a shelter for
> my loading coil from 47 x 47 mm preservative treated timber
> covered with plastic sheet. This doubled the loss resistance of the
> antenna, and it was obvious that the wood had a high moisture
> content. Replacing the original wood with thinner, kiln-dried stuff
> solved the loss problem. Then the plastic sheet developed a leak,
> one piece of timber got wet, and the result was a minor fire - luckily
> I caught it early. The rebuilt shelter uses heavier polythene
> sheeting which is more carefully sealed, and has stood up well to
> the wind and rain of the last few months (fingers crossed!). The
> high voltage antenna connection passes via a ceramic feed-
> through mounted in the middle of a rigid plastic sheet which forms
> the roof. The feed-through by itself did not have adequate
> insulation. I have also installed a cheap 1kW fan heater, so the
> whole lot can be dried out from time to time. I think thoroughly
> varnishing the wood woud help a lot, but this is a job for next
> summer.
>
> I would certainly be interested to hear of a material for making
> loading coil shelters which is at the same time fireproof, a good
> dielectric, and easily worked.
>
> Hope you are back on air soon, Dave,
>
> Cheers, Jim Moritz
> 73 de M0BMU