Re: Cage type secondary former

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

At 06:27 PM 5/12/2003 -0600, you wrote:
>Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>
>
>Hi Steve,
>
>My local plastics guy just says to get thin plastic (I think he said 
>Lexan, but I am not sure) and bend a flat sheet over into a tube and glue 
>it up.  I didn't get all the details since it was busy wildly diving into 
>the free scraps bin, but he seemed to think it was a real easy thing to 
>do.  I am not sure how the seem is made but this guy can glue edges that 
>are invisible with solvents that "melt" the plastic edges together just 
>like they were made that way.
>
>Cheers,
>
>         Terry


Exactly that... you can get nice "glue" for both polycarbonate and acrylic.

The other approach is to get very thin plastic and wrap several layers 
around the form and use something like CA (or Saran Wrap?) to hold it 
together until you get the wire on it.

However, might I suggest that you look at plastic trash cans.  They make 
nice circular trash cans that are about the dimensions you want.  They have 
no taper (think of those ashtray/sand/urn things you (used to) see in hotel 
lobbies, next to elevators, etc.

Just a little browsing on Rubbermaid's web site turns up things like the 
#3550 rigid liner, 12" diameter x 27 1/4" high (doesn't say if it tapers, 
though)..

Consolidated plastics is large mail order retailer of these sorts of 
things.. you might look at polyethylene tanks or drum liners? There are 
also 22 gallon round station containers in a lovely blue that say "We 
Recycle" on them..

You get the idea...




>At 08:47 PM 5/12/2003 +0100, you wrote:
>>Dear list,
>>
>>I've been wracking my brains to try and find a suitable former for my 
>>OLTC secondary. I was looking for a thin walled plastic pipe 10" dia x 
>>30" long. Then I thought, why do I need to use a large pipe at all? I 
>>could make a round cage-like structure from a number of 30" long PVC 
>>drain pipes and a top/bottom/stiffening plates made out of PVC or wood.
>>
>>I'm not sure if this would work, though. On the plus side it might have 
>>lower losses since the winding is mostly in air. On the minus side 
>>though, the field control might be poor because it's not perfectly 
>>circular and there's no way to fit baffles. Mind you, I noticed Bill 
>>Wysock's Super Model 13M used a secondary/extra coil wound on a wooden 
>>cage and it seemed to perform reasonably well &) However, just because it 
>>works for a 30 foot tall 700 turn extra coil doesn't mean it'll work on 
>>mine... Has anyone ever tried an open frame secondary like this on a more 
>>realistically sized coil? How did it go? Was it a pig to wind?
>>
>>TIA
>>
>>Steve C.