Nor should those original techniques be used again. Another problem with 3rd generation builder methods is that the original materials have changed, or are not even available anymore. Zephyr Skin pouch material is one good example. Use what you can buy today, and you'll be very sorry soon enough. So here is a good example of an original material that is just as disastrous as Perflex.
Leather is another good example.
In the heyday of the player piano, leather was a huge industry, and the leathers used were wonderful stuff, almost all of it industrial leather grades. That means, the collagen fibers are not compacted and the skins are not pre-stretched or staked during tanning. The pouch leather is no longer from registered herds of 2 year Scottish sheep bred specifically for the product. The rubberized cloth can be made identical, but when it is, it is very expensive, and there is no ability to really check and see what the factory sent you. So the professional rebuilder must take this and much more into consideration and take special precautions sometimes with what he has to use, if it is to last as long, and endure the same usage as original materials could take.