Tips on using the Water Soluble Glues…… These glues have a milky appearance and they are rapidly absorbed by porous leather, especially the underside of leather. To get results you need to apply 2 coats of the glue. Apply a generous coating of the glue to both surfaces to be joined then let this dry completely. (say 1-2 hours). This first coat of the glue will soak into the leather and most of the adhesive properties are lost however it forms a binding substrate that the next coat of glue will adhere to. Apply the second coat and wait until it is tacky, then join the 2 pieces of leather together.