We are working on a project placing permanent numbers on unfinished wood objects (furniture parts) by means of a base layer and topcoat of B72 with the number written with a .01 micron pen. We have encountered problems with bubbling of the B72  / goopiness, so that it obscures the number once a topcoat has been placed over. When we try to remedy the goopiness by adding a bit of acetone to the B72 mixture, it causes the ink to smear. We are trying to find the best solution (pun intended) because we cannot use tagging. We have considered pencil only and also just using a base coat of B72 with no top coat. Any suggestions? Thanks.