I have had pretty good results using this plywood from Amazon, they have other sizes, you may be able to find one that will fit in your laser natively. I have a wood shop also, so I buy these, and cut them to 12x8 which is the size of my laser bed, and get 60 sheets from a box.
This is 3mm Birch Plywood that I bought from Amazon here: https://www.amazon.com/Premium-Baltic-Birch-Plywood-Grade/dp/B016H589HC?ref_=fsclp_pl_dp_2
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And the honey is made of Acrylic Resin and an amber tint. The resin has about a 30 minute working period and takes around 24+ hours to fully set. The pours were done in different batches and on many of the hexes I had to pre-coat with resin so that they didn't later leak out of the bottom.
I buy 3mm birch plywood off amazon probably the cheapest I’ve found it