Blow up your top load !

[pentode]

Building my DRSSTC and considering my top load construction.
Bought the standard ali ducting to make it but had a mad thought...…

Scooter, garden tractor and car inner tubes are very cheap to buy,
SO. blow one up, cover in ali foil. Job done !!

The inner tube valve could be sealed for good or if
you consider inner tube may deflate over time then leave it.

Any thoiughs?

[Hydron]

This has been done, though not by me. I think people have used papier mache over a tube before the aluminium layer for structural integrity, but it all sounds like a lot of work.

For my smaller coil I bought a spun toroid off eBay, for my larger one this wasn't practical so I used ducting. For my first go I used alu duct and while it worked it was _very_ fragile. I've now replaced it with some single-wall stainless steel flue liner which is massively stronger, though more difficult to work with. This stuff is easy to get it in the UK, though difficult to source in NZ where the coil was. Ended up finding a UK eBay seller offering international shipping via the eBay global shipping program - normally a ripoff but in this case a rather large box was only £12 to the other side of the world (must be done by weight rather than volume!).

[Teravolt]

I also use flexible ducting it is easy to get and cheap but I have seen pictures of donut boloons covered with paper mashay and aluminuim foil.

[Mads Barnkob]

Peter Terren from Tesladownunder.com did this some 12 years ago on his largest SGTC: http://tesladownunder.com/Tesla_coil_18inch.htm#Toroid