[TowerTalk] Fibreglass rod sources?

[K8RI on Tower talk]

> Building a 80m vertical from Rohn 25g sections and need some fibreglass 
> solid rod; 1.5" OD,  preferably

I see I'm not the only one who transposes.  Industry wide, the generic name 
is fiberglass (not just in the US)

IF all else fails, you can always make your own using fiberglass cloth/rope 
and epoxy, or Vinyl Ester Resin.
They make wing spars by laying a bunch of the rope in a foam chanel and 
soaking it in Epoxy, the West System being the most popular.  You'd normally 
use the rope (unidirectional fibers) for strength in this case and then wrap 
the whole thing with a couple of layers of cloth.

I believe "Aircraft Spruce"  http://www.aircraftspruce.com/ would have the 
required materials
Look under Cozy or LongEz and in particular for spar materials.  If you 
don't find what you are after, a phone call *might* help.

If you are familiar with the materials this is a very easy process that will 
produce strong and reliable results, if not it can be messy with less 
reliable results. OTOH it _can_be a whole lot less messy than turning down 
fiberglass in a lathe.  You not only need to wear a good mask and eye 
protection, but a good, high voulume air filter, such as a whole shop air 
filter, placed close to the work is a very good idea or the whole area gets 
a coating of the abrasive dust.   With a bit of creative imagination, some 
practice, and a little luck the learning curve is fairly shallow and 
*short*.  There are a number of short tutorials on using fiberglass and 
epoxy or resin on the net.  A Google on "West Systems epoxy" should turn up 
something.

As I'm building an airplane I do a *lot* of fiberglass sanding and grinding. 
I built my own "whole shop filter" by using a $16,  20" window fan and a 
deep pleated furnace air filter to match.  You can build a frame of just 
Duct tape the filter to the inlet side of the fan.  The deep pleated 
filters, although expensive (they may run up to $30 in some area) work 
better and far longer than the one inch thick ones normally used. OTOH for a 
few days use the $3 to $5 ones are plenty sufficient. I found 4 of the deep 
pleated ones in a discount building store that had been damaged in shipment. 
The only thing wrong was either the paper frame was torn over the face in a 
couple spots, or the side was dented with the plastic wrapping torn off. If 
I remember correctly, I got all four for $20 to $30 and they work as good 
and the ones that look nice.

On  http://www.rogerhalstead.com/G3_files/G3-9_files/glasair9.htm about 2/3 
the way downt he page is a photo of the cheap filter I constructed.  Using 
those filters or even the one inch thick (5 micron or even 20 micron) close 
to the welding area even took the smoke out of the air.  Prior to using the 
filter the whole shop would turn blue with just a short welding session. 
Now I set the fan near the welding bench and I can weld for half an hour and 
the air in the shop will still be clear.  As I said, these are *cheap* but 
they work well. Unfortunately they are very fragile (I did use the word 
cheap) and this is my second one. The one inch filters are good for a couple 
of weeks, depending on how much dirt I put in the air.  The think ones, as 
shown in the photo are good for about 6 months under the same conditions. 
Typically the fan runs 24 X 7.

 On  http://www.rogerhalstead.com/G3_files/G3-9_files/glasair9.htm about 2/3 
the way downt he page is a photo of the cheap filter I constructed.

Generally the fiberglass and epoxy rods are quite sensitive to UV so you 
need to come up with some form of protection.

Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
www.rogerhalstead.com

>1.75" OD, to insulate/isolate  the Rohn 25 tower base section. Besides 
>Max-Gain Systems (only have up to >1.5"), where are my choices? A search on 
>fibreglass, fibreglass  rod gets me lots of fishing poles!
>
> Mike, K5UO, 9H3UO
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