yes, but isnt the case that if the leads too thin, you cant join it? The guy was only talking about the rubber in the context that either the lead was too thin and couldnt be joined or it was preferable to remove the existing lead completely and replace with the rubber stuff due to the fact that no one knows how far up the render the lead goes.
Saying that - I've noticed some of your past posts - you aint a fan of the rubber then!!
Saying that - I've noticed some of your past posts - you aint a fan of the rubber then!!