[TowerTalk] Adding Expanding Foam inside boom

[David Gilbert]

Most commonly available foams actually crush pretty easily.  After all, 
they are just bubbles with a flexible membrane surrounding each bubble.  
Another factor is that whenever I've tried to use the foam to fill a 
really large gap, the bubbles formed are not of uniform size ... the 
interior ends up with really large bubbles that would have no strength 
at all.  It's easy to make a big glob of this stuff in a plastic bag, 
then cut it open to see the effect.

I also agree that the extra weight probably offsets what little 
additional strength that might result from the foam.

Dave   AB7E


On 4/26/2018 8:42 AM, Charles Gallo wrote:
>
> The foam might not give you ANY extra strength, and even you look at
> strength/weight, I'm going to guess it'll be a net negative.  Now if you
> know your boom has a vibration problem, we are talking another story.
> Even then, there are probably better ways to make the boom stiffer (put an
> end cap on both ends, attach a cable that runs inside the boom from end
> cap to end cap, and come up with a way to tension the cable - aka put the
> boom under compression, or put a metal ROD in, and put the boom under
> tension - both will change resonance)
>
>