Re: [APML] Home-made Dew Heaters Redux

[Herm <hermperez@worldnet.att.net>]

Hi Roland, the stuff I use is sold at Wallmart and comes almost ready to
use.. its stainless steel fishing leader, nylon coated, 20lb test. I forget
what the resistance per foot is but its easily measured. I normally use two
loops to do a C8. You can parallel the strands if you need lower
resistance.

The insulation is thin (but quite tough) so be careful the strands dont rub
on each other.. best setup is a semipermanent one on the scope. This is how
I do it on a C8:

1. lay down a strip of 3M electrical tape, sticky side UP.. this is the
hardest part.. around the ota.

2. prepare your loops (either single wire or parallel) with their crimped
connections to flexible wire of your choice.

3. now, neatly wrap the wire around the ota, sticking the wire to the
exposed glue of the electrical tape..

4. once you are satisfied on how it looks, wrap another layer of 3M
electrical tape, sticky side DOWN, that covers the wires and the first
layer of tape.

5. somehow strain relieve the flexible wires, I just use more tape. 

Disadvantage with this method is that it is semipermanent, but in any case
I always use the antidew heaters and it saves setup time not having to
remove them everytime.. cost is very low, under $5 inlcuding the tape.

Only use 3M electrical tape, its non hardening, sticks good and the glue
never oozes all over the place. Its available in many widths and colors.


Roland Roberts <roland@astrofoto.org>  wrote:

>I've been looking into this more because I want to make several to
>cover both my telescope and eyepieces as well as my camera lenses.
>NiChrome wire is normally sold "bare" as opposed to coated e.g.,
>magnet wire.  Does anyone know of an easy way to coat such bare
>strands so they could be coiled without shorting?
>
>roland

Herm
Astropics http://home.att.net/~hermperez

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