0

Below is a pattern plywood cutting board I am making. I have observed through multiple projects that after sanding the surface becomes dull in tone and the layers of the plywood lack definition and sharpness. The portion circled in red is unsanded and the portion circled in blue has been sanded. You can see the dullness of the sanded area.

I notice that if I raise the grain by moistening the surface that the definition is restored, but upon sanding again it will dull.

Why does this happen and how can I avoid it?

Patterned plywood - sanded vs. unsanded

4
  • 4
    Isn't that just sanding dust? Try cleaning it with compressed air, a tack cloth or some mineral spirits. Also, how fine is the grit you're sanding to?
    – Eli Iser
    Dec 1, 2022 at 22:56
  • It's just sanding dust (white/off-white) in all the little irregularities of the wood. You get the same thing with almost all woods but it's restored by the application of any finish which 'wet' the surface. BTW if you just dust really well all or almost all of that will go away normally, but since this is ply and half of the sanding is into end grain the effect would be more persistent than e.g. on a tabletop.
    – Graphus
    Dec 2, 2022 at 7:29
  • @EliIser "Isn't that just sanding dust?" Well, I had no idea! But now I do! :) I tried the compressed air and WOW. I literally would never have expected. These results are actually from 180 grit.
    – Matthew
    Dec 2, 2022 at 19:32
  • @Graphus Please also see my reply to Elilser. I now understand this is dust and the "problem" appears to be magnified by the layering of the plywood, the adhesive, etc. It just never occurred to me up front that it was dust since normal wiping doesn't clear it. It required a wet rag or compressed air to remove the dust. If one of you guys wants to put as an answer I'll mark it as accepted. Thank you again.
    – Matthew
    Dec 2, 2022 at 19:35

1 Answer 1

4

This appears to be sanding dust. It's typical for wood to lose its luster when sanding as the sanding dust clogs the surface of the wood, making it look dull. A brush, compressed air, a tack cloth or a cloth damped in mineral spirits (as water would raise the grain) can all be used to remove the sanding dust.

With that being said, there is a difference in how wood looks between cutting and sanding - sharp cutting tools (hand planes in particular) can leave a finish on the wood that's hard to replicate with sanding (even to very high grit), as the wood fibers are cleanly sliced instead of being abraded. Adding a finish on top of that tends to reduce the difference, and leaving a piece unfinished will dull the look from use and handling.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.