Wet sanding solid relief printmaking blocks, such as the Cherry Woodblocks I make, can create a smoother surface to print on, and reduce grain raising when using water based inks as in the Japanese methods.
Carefully sanding damp surface - considerable skill is required to do this whole process.
With many years experience in working with wood, this is something I do, my methods are briefly outlined below.
Wet sanding is the final stage, applied to an already flat and smooth surface. I do this on my solid Cherry Woodblocks, which I have hand planed very flat (to within a few thousands of an inch), and which are already very smooth (which I have printed from without wet sanding).
As I use no machines, and certainly no sanding machines, my surfaces are already planed along the direction of the grain. A sanding machine wouldn't do this, nor would casual hand sanding (unless it was only done in direction of grain).
I have no experience of wet sanding rougher surfaces, and do not if what I do below is suited to such surfaces. My guess would be to finely sand in the direction of the grain only first.
Tools I use are very simple. Alongside the wood block I made below, I use the following:
Wet sanding woodblock tools
There is more than one way to crack a nut. There is more than one way to wet sand, or reduce grain raising on wood surfaces. I do not pretend this is the 'best way' - it may not be. However, it works for me, so I use it.
Note: I have many years working with wood, hand planing, hand sanding and applying certain types of finish. Even so, I always try new procedures on scrap wood until I get it right, including a test print where necessary - I would strongly suggest you do too - you might ruin a good surface otherwise.
Using my fine water mister, I spray a little water on the surface, and spread it gently around with my fingers. I don't use too much - experience tells me how much. I'm not trying to soak the surface - but equally too little doesn't sand right. Test on scrap wood first!
Spray on a little water first
Gently spread water over surface. Correct hand action uses maximum surface area of fingers, keeping finger nails well away from surface lest they mark it.
Now I gently sand with my wet and dry paper. As my surfaces are already very flat and smooth, I can start with 400 grit. I use light pressure, using the pads of a few fingers - not letting those finger nails get anyway near the surface.
If your surfaces are less smooth you will need a coarser grade - may 180 or 240. Test on scrap piece first - use too coarse paper and you'll ruin the surface and have a lot of very careful sanding to do.
Sand with the grain direction, in straight lines. Sanding across the grain, or in circles will ruin the surface. Wood fibers are akin to straws stuck tightly together - go along the length of the staws to get a finer surface. Going at right angles to the straws will just scratch them and spoil them, leaving lots more sanding to fix it.
Gentle first sand with wet and dry paper.
With paper towels, I gently dry the surface, wiping along grain direction, removing wet saw dust on surface left from first sand. For me, this tends to clump together, so I need to be careful to wipe it off carefully. Leaving it makes next step harder.
After carefully checking surface (that it is smooth & no dents), I repeat steps 1-3 again with 600 grit paper.
Rewetting surface again, then will spread gently with finger tips
Re-sand with 600 grit paper, only along wood grain
Carefully dry surface again
Whether or not I will use both sides, it is vital to wet sand both sides the same. Wood is a natural product which grew with large amounts of water in it. Treating only one side could introduce stress into the timber, leading to cupping/twisting etc., which could ruin a very good block.
Carefully check block.
After carefully checking block, I leave to dry, upright. Vital that both surfaces dry at an equal rate, otherwise may introduce stress into timber, and it may cup / twist out of shape.
Block should be left fully vertical - however for photo below I couldn't do that - however you should - and don't let things touch the surface while drying.
Leave away from sunlight, and away from heat sources. Let it dry slowly and naturally - don't force it - you'll regret it.
Leave to dry - but it should be upright, not on side like here!
Once dry, block can be stored or used. If storing, I always store upright, out of sunlight, and not near heat sources.
Copyright & Disclaimer
All information & photos are subject to copyright and disclaimer, outlined at bottom of page.
All prices subject to change without notice.