Re: PVC vs. sonotube, (was wondering ) (fwd)

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Original poster: List moderator <mod1@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Sun, 03 Jun 2007 11:59:00 -0700
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: PVC vs. sonotube, (was wondering ) (fwd)

Agree with John here except in the sonotube category. In my use of 
sonotube, I had no problems with heating or performance. I imagine much 
depends on the quality of the sonotube itself (impurities or lack of). 
When I built my sonotube, I thinned out varnish (varnish and paint 
thinner) so that I had a very liquefied coating. I coated the inside and 
out several times with the thinned varnish (wanting it to soak into the 
cardboard) then finished off with a couple coats of unthinned varnish. 
Wound the coil and then coated it with thick marine spar varnish. Coil 
ran great.

I know some coilers have had great success with sonotube and some 
coilers have had miserable failures. I'm not sure why the division 
exists unless prep is part of it or if it's just the type of sonotube. 
My sonotube was called Quikrete and I think I purchased it at a Home 
Depot in Minnesota at the time.

For small coils under 8" diameter, pvc would be my choice. But as the 
coil gets larger, pvc gets "heavy" and thick. Sonotube does have the 
advantage of size vs. weight, but it is also more difficult to machine 
end caps for. If sonotube is not treated, it will acclimate with the 
weather and humid climates will definitely have problems (as Terry Fritz 
found out while measuring sonotube and saw a major changes when it rained).

Take care,
Bart

Tesla list wrote:

>Original poster: List moderator <mod1@xxxxxxxxxx>
>
>
>
>---------- Forwarded message ----------
>Date: Sun, 3 Jun 2007 13:15:40 EDT
>From: FutureT@xxxxxxx
>To: tesla@xxxxxxxxxx
>Subject: Re: PVC vs. sonotube, (was wondering )
>
> 
>In a message dated 6/3/2007 12:01:37 P.M. US Eastern Standard Time,  
>tesla@xxxxxxxxxx writes:
>
>  
>
>>Hi  all,
>>     I know the best material to use as a coil  form would be either HDPE 
>>    
>>
>or styrene, but if pvc is the best available  choice,  would milling grooves 
>lenthwise down the form make it less  lossy?   I'm sure it would be a pain in 
>the butt to do, but wonder  if it would be worth the trouble.
>  
>
>>     Also,  I  cannot seem to find info on whether a sonotube would be a 
>>    
>>
>better choiice to  reduce losses in the form.
>  
>
>>   Mike
>>    
>>
>
>
>
>Mike,
> 
>In reality, PVC is not very lossy for TC use.  You won't see any  difference 
>in performance using PVC 
>vs. styrene in a disruptive TC.  Even for a tube coil, which is more  
>sensitive to losses, you
>probably won't see a difference in performance.  The biggest potential  
>problem with PVC
>is carbon tracking and burning.  This only occurs if the coil is  overcoupled 
>or subject to
>flashovers, arcing, etc.  Some folks advocate baking and sealing the  pvc to 
>keep moisture
>out.  In 90% of the cases, folks don't bother with that.  So to  answer your 
>question milling
>grooves is not worth the trouble.   Sonotube can be very bad  depending on 
>how it's made.
>I tried it for a tube coil and it got hot.  Performance was  miserable.
> 
>John
>
>
>
>************************************** See what's free at http://www.aol.com.
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>