Hammering the edges of fiberboard is a neat trick! Vegetable-tanned leather is pricey where I live, too. I've sometimes wondered whether I could very thin belly offcuts cheaply and laminate them. Working with the thicker leather, it feels like I skive away a lot of waste. I imagine water could also soften up fiber stiffeners, as well, and without all the volatiles of lacquer thinner. Many shoemakers use modified-starch paste-water and starch-on leather stiffeners anyway.
Thanks for stopping by again. Yes. Water can do the job so if you are using water based pastes certainly use water. Most people around me use contact cement and don't like to wait for long before moving on to their next steps hence the recommendation of thinner. I know water will work very well even if contact cement is to be used but one has to let it dry properly.
