[TowerTalk] A couple of 18HT questions

[Kelly Taylor]

It's hard to tell from the Hy-Gain owner's manual or parts list, but...

Are they really selling aluminum base tubes to embed in concrete?

I'll take the OP at his word, but given what we know about aluminum and
concrete, it sounds like a major liability issue waiting to happen.

Then again, don't the Bencher HF-series of verticals suggest
concrete-encased aluminum as one base option?

73, kelly
ve4xt


On 12/17/14 1:47 PM, "Jim Lux" <jimlux at earthlink.net> wrote:

> On 12/17/14, 11:16 AM, Gary Schafer wrote:
>> Hi Allen,
>> 
>> You do not want concrete in contact with aluminum! It will eat up the
>> aluminum. Even aluminum windows come with a warning to not let the brick
>> mortar come in contact with the aluminum frame when installing.
>> After the concrete is set and dried it may be ok then, not sure.
>> 
>> 73
> 
> Yes indeed.. Aluminum is readily attacked by most acids and bases: the
> surface oxide helps a lot, and, of course, a chemical conversion coating
> (anodize, alodine) would too. BUT, a scratch in the coating provides a
> nice surface to be attacked.
> 
> ALuminum is attacked by most basic hydroxides (e.g. sodium hydroxide,
> lye, is used to etch aluminum panels).. It is a way to make hydrogen
> gas, in fact.
> 
> Mortar is a mixture of quicklime (CaO) and sand, for the most part, and
> when you add water to it (slaking the lime) it forms Calcium Hydroxide
> (Ca (OH)2).
> 
> Concrete has similar chemistry.
> 
> So, yes.. keep your aluminum out of the concrete footing.
> 
> _______________________________________________
> 
> 
> 
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>