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Re: Blown Rolled "Hull" Capacitor Discussion

>>From pxeyoung-at-mailbox.uq.oz.au Sat Mar  2 09:12 MST 1996
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>Date: Sun, 03 Mar 1996 01:43:10 -0600
>To: <tesla-at-grendel.objinc-dot-com>
>From: Marcus Young <E.Young-at-mailbox.uq.oz.au>
>Subject: Re: Blown Rolled "Hull" Capacitor Discussion
>
>Bert and coilers, 
>
>>One of the problems that you can run into with PVC pipe and PVC end caps is 
>>that if you try to use a good vacuum pump, you can suck air THROUGH the PVC 
>>end caps!  I put a vacuum pump on one of my caps after filling with oil to 
>>see if I might be able to coax some additional air out from between the 
>>layers of plastic and aluminum.  I was pleased to see a lot of bubbles 
>>rising up thru the oil.... only they never stopped.  I became suspicious and 
>>poured some oil into a capacitor housing that had no cap in it and connected 
>>the pump.  Sure enough, the vacuum pump could pull air right thru the pvc 
>>plastic end cap.  Although a vacuum can pull air through the plastic, oil 
>>will not leak out.  The result of trying to use a vacuum pump was that I 
>>ended up sucking millions of air bubbles INTO my capacitor, not what I was 
>>trying for.
>>Anyone else tried this with better luck?
>
>If you can get access to a vacum chamber  youlle be in business. Equal vacum 
>over the entire capacitor will insure that air is not sucked through the
>capacitor casing and you can do away with making the cap vacum tight. Sealing 
>of the top can be done after the cap has been evacuated. Ime having a local 
>transformer manufacturer complete this part of the proscess in exchange for
>a carton of beer. 1 carton of beer=6 hard vacumed polycaps. Its good to make 
>a freind at your local transformer/power supply manufacturer! :) A real handy
>contact indeed. If this isnt an option, I might suggest even building a vacum 
>chamber of an improvised design. Ime sure many other uses could be found for it
>once you had it. Any suggestions out there on how to improvise a decent 
chamber.
>The ideal scenario is to be able to introduce the oil into the capacitor after 
>a vacum has been pulled on it. This way your not removing bubbles from oil, but
>completley removing bubbles from the proscess!....well except for bubbles
>allready present in the oil. With this method you wont have to worry about
>stress fractures in end caps or leaks caused by distortion of the capacitor
>casing. In addition only the bottom cap need be initially sealed. A lighter
>'dust cap' can be used at the top, which can be sealed after the evacuation.
>Making each cap into a self contained vacum chamber will allso add extra 
>construction time.......unless you only plan to build one. 
>
>Suggestions on inexpensive vacum chamber designs or improvisations??
>Ime thinking along the lines of an epoxy sealed 8" PVC pipe the overall 
>design much the same as a Hull caps' case. Any ideas for constructing 
>a vacum gasketed removable top plate/observation window?
>
>Marcus  
>
>

Marcus, I like the idea of a vacuum chamber, but I don't think of anything 
on hand that I could use that would work.  I do like the suggestion of epoxy 
sealed pvc!  I guess we should not only be sealing our pvc coils, but caps 
as well.

Bert