RE: Re[2]: First light...Sort of

>Original Poster: Aric_C_Rothman-at-email.whirlpool-dot-com 
>Since I made an enclosure for the RQ gap that includes a 1 HP vacuum 
>motor for cooling/quenching, I'm thinking about building a new RQ gap 
>with the same form factor.  I think I erred in using the same tube as 
>my secondary coil form as support for the RQ gap.  It's the 
>thin-walled, sickly-green PVC pipe used for low-pressure waste lines.  
>Has anyone had similar problems using the thick PVC?  Would the 
>chloronated PVC be a better choice.  What bonding method should be 
>used to join the Cu pipes to the PVC?  I used JB Weld (epoxy) followed 
>by Pop Rivets.
>What is another more heat-resistant material, available in a 4" OD 
 >tube, that would be more suitable than PVC (excluding such 
>astronomically expensive options as phenolic and teflon tubes).  

The enclosure for such a cylinder gap needs to be made out of a thick walled
material, not only for better heat resistance, but for general stability.
The thin stuff flexes too much and the gap spacing shifts as a result.  Home
Depot sells some thick-wall PVC couplings  for 4" PVC pipes, already precut
to a nice length.  I used a small piece of G10 fiberglass between my copper
pipes and the PVC surface,  although I'm not sure the pipes ever got that
hot that it was necessary.  Do you have a fan blowing over and cooling your

I just used 1/4" screws and nuts to secure the pipes.
You can see my cylinder gap at:

Regards, Gary Lau
Waltham, MA USA