[TowerTalk] [Antennas] Carbon Fiber Boom

[Tod -ID]

If people are going to speculate on  applications why not consider replacing
the Chrome-moly masts that weigh an incredible amount with a mast made from
carbon-fiber composite. One would not need to worry about machining. 

I wonder if a 2 inch diameter by 15 foot long mast would be more or less
expensive than the high strength metal alternative? Did someone give the
yield stress numbers on the reflector? If not, does anyone have an idea what
they would be?

Tod, K0TO

> -----Original Message-----
> From: Roger (K8RI) [mailto:K8RI-on-TowerTalk at tm.net] 
> Sent: Saturday, November 10, 2007 1:17 PM
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] [Antennas] Carbon Fiber Boom
> 
> 
> 
> 
> > >Carbon fiber
> >>probably demands special methods of attachment, drilling, fittings,
> >
> > Who needs drilling and fittings?
> >
> > Buy some carbon fiber fabric, some epoxy, and really good gloves.
> > Sand the boom a little.
> >
> > Make a jig to hold your aluminum element center section at a right 
> > angle to the boom and just wrap the joint in epoxy coated carbon 
> > fiber.
> >
> > Let it cure ... done.
> 
> But if you ever want to disassemble it, that's one expensive 
> joint to cut apart.
> Also, just wrapping it up doesn't give the best strength and 
> with large antennas this is important if you want maximum 
> strength with minimum weight. 
> Fiber orientation and type of cloth is very important for 
> maximum strength with the minimum of materials.
> 
> Typically for this type of joint fiberglass and resin is more 
> than suficient and a whale of a lot cheaper. The carbon fiber 
> boom is where the light weight and strength really would come 
> into play.
> 
> If a person has the equipment or skill with hand tools hard 
> wood blocks can serve as molds for building element to boom 
> mounts/clamps. For me, lacking the skill with hand tools, a 
> milling machine works wonders at making molds. 
> Cut to shape, sand smooth, give several coats of Verithene 
> (sp?), let cure, coat with mold release (non silicone car 
> wax) and have at it.  It's a little more complicated than 
> that as it takes two halves for each and they have to 
> properly fit the boom and element, but if one likes to 
> experiment it can be fun.
> 
> Roger (K8RI)
> >
> > Go to the local fancy bike shop if you need ideas on how to attach 
> > aluminum to carbon fiber ;-)
> >
> > Dan
> 
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