I have used "Super Cloth tape" (www.stokvistapes.com) to repair my 5x7, 8x10 Sinar bellows. Works very nice. Stretch your bellows and you will see that it is not that complicated as it may appear. Just put the tape over the corners/edge all the way from front to back. Good if you can put your hand or fingers inside the bellows. After my repair my bellows are light tight and works properly, but they are quite large bellows I must add - perhaps more difficult to work with smaller bellows, have not tried.
Best wishes
//Bertil
The links not working but I've used a virtually light-tight cloth tape (self adhesive) made I think in Holland, bought from a haberdashers in the UK, it's extrememly strong and thin with very good adhesion. I used it inside and out on a set of badly damaged Speed Graphic bellows, it's very difficult to spot the outside patch and it hasn't impaired the bellows folding normally. I did post the amke somewhere in an APUG thread last year.
Ian
I painted a bellows with "liquid electrical tape" and after a thorough drying, is quite light tight. I've also read that fabric paint from a fabric or craft shop works equally well.
I can confirm that "Liquid Electrical Tape" works really well. Recently tried on 3 cameras. Worked just well. Sometimes need to coat more as 1 time but it it ok.. Also tried "elmer's glue" method - don't do that. Does not work well.
Vic
"Bellows repair is not recommended" - I'm completely disagree with that. I recently got few folders - 2 ansco speedexes, 1 zeiss ikon, 1 bessa, and 2 agfas. Nothing that special but all 6 still may produce amazing pictures. All 6 had minor issues with bellows (minor I mean 3-4-5 pinholes). Replacement will be close to $300 when total price spent to purchase all these 6 cameras was little bit over $70. So my personal conclusion - it depends on what camera you would like to replace it and what is the reason (does it really worth "investment"?) . In my case replacement just is not smart move at all. I would better spent $$ buying more cameras IMHO