I've replaced 3 Technika bellows and a Fuji 645 bellows over the last few years. I used contact cement with no issues. Contact cements sets quickly, but it usually can also be removed without causing damage. I had to remove a new bellows I had just installed in one camera to put in another camera that I needed to use. This all went smoothly without problems, since the contact cement allows removal. This is why contact cement is always used for camera leather coverings. It holds well, but can be removed later without causing damage.