Advice needed. I sanded the tops of these kiln dried rounds and then coated both sides with shellac. Most of them split a few days later.

The untouched rounds have been stable.

How can I make these smooth and shiny and keep them intact?

  • potate@lemmy.ca
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    1 year ago

    I think some people use a vacuum chamber and epoxy to stabilize the wood. I also wonder if soaking the biscuits in a mineral oil bath for a few days might do the trick? Personally I’ve never had much luck with larger pieces.

  • DavidP@midwest.social
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    1 year ago

    My guess is that the alcohol rehydrated the cells, causing them to expand and then shrink back. This might have introduced just enough stress for them to split.

  • jadero@lemmy.ca
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    1 year ago

    I find it interesting that the untouched rounds are (so far!) doing better. I don’t have any answers, but I’ll speculate.

    Shellac is pretty permeable to water vapour. I don’t know how much it slows the exchange of water vapour, but it might not be much.

    I would be curious how sanding alone affects stability. I can imagine sanding increasing the surface area exposed to the atmosphere, speeding up the exchange of water vapour.

      • jadero@lemmy.ca
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        1 year ago

        While you’re at it, maybe plane or scrape a couple of rounds, too. If sanding marks and raised grain really do increase the exposed area, getting rid of them will reduce it.

        I would think someone out there has already done the experiments, but I didn’t find anything with a quick look.

        Also, if you’re not committed to shellac, there are coatings that are less permeable to water vapour.