Where to buy long lengths of square elastic (not the covered dressmaking type)?

Just possibly ... Aeromodelling suppliers? They would have to supply parts for rubber-powered models though ... not sure how popular they are nowadays

J^n

The core of bungey cord, from yacht chandlers if a very long length required, not particularly even sections of each cord though

The Kum Bak elastic was rather different from aeromodelling grade rubber.

You might find 1/16" rubber strip suits

Or just eBay (bungee or shock cord); no need to pay the mark-up at chandlers, which is a bit like the mark-up on horse stuff.

But not as bad as camping shops.

Bill

Catapult rubber? Or is this just my misspent youth? eBay offers 2m lengths at first peek.

See above, I've found that but it's too thick.

Yes, I was thinking of Mike Woodhouse's site but didn't look it up. I see he is close to 80 now - probably 40+ years since I first bought some bits from him...

Model aircraft rubber ? Quite hard to find these days in the days of cheap (and light) electric motors and batteries

Do people still make the rubbery stuff we used to use in model aircraft powered by rubber bands? You used to be able to get whole reels of the stuff and use as many loops as you liked, smear it in preserving oil and off you went. I wonder how you measure elastic? Brian

How do you attach the ball, the ones I saw had the ball with a hole in it and it was threaded through the middle and knotted, but when I tried to drill into a tennis ball some years ago to make a kind of fender, there was a gooey liquid inside. Brian

The ball has a sewn on little loop, I've bought some more similar from 'modern' tennis trainers which are just about exactly the same so they'll do well for ball replacement.