Alum on wood?
- I speak only for myself here: yes, I alum the wood after it has
been sanded smooth and wiped clean. If the species is on the
soft side, I sometimes dampen the wood after sanding, let it dry
completely and repeat the sanding/wiping to take down the
raised grain, then alum. However, sometimes there are resins
lurking in the wood that can't been seen or felt . This will cause
patchy spots in the marbled pattern. I find that woods such as
maple and walnut work exceptionally well as they are tight
grained and respond to marbling like the surface of fine paper.