I ran into a serious problem with my latest purchase of Baltic Birch Plywood from my local wood supplier. I have used the material from them before and it worked fine. Their latest 1/8 inch supply will not cut through and the char left on the board is pitch black, not the usual medium brown. Even using my usual settings for 1/4 inch material does not consistently cut through the material. When went back to the wood store to discuss the problem the gentleman who does their purchasing showed me that the manufacturer apparently used outside grade glue rather than the usual inside grade glue. It is visible as two dark lines between the plies. It should have been something the same color as the wood. They are kind enough to give me a refund.
I thought this experience is worth passing along to the Glowforge community.
I am sure your problem is the material between the 2 Baltic birch layers on the outside of your wood. Proofgrade has a cardboard filler so they know how the laser will cut through that. Store-bought wood has different fillers which cac be a problem. Slow your cut speed down by 10 or 15 and try some test cuts. Also remember that if you don’t move your wood in the laser you can make another pass and save your wood. I have a dental tool that I use to check all of my cuts with so I don’t move my wood just in case something didn’t cut through.
Sometimes filler stuffs are just impossible to cut through with this laser. You never know until it happens. Somethings can be checked for with a strong light but it’s just what it is.
I had that same problem. Bought the 1/8" and 1/4" sheets from a different lumber store than I had used before, and had extreme black charring, and needed 2 passes to cut through. I had already cut the sheets to Glowforge size, so everything made with that material requires washing the edges with a toothbrush and water to get rid of the char.
I recently went and bought sheets at another lumber yard, and now I am back to proofgrade equivalent material (and it was cheaper!)
That’s absolutely fabulous, and a supplier worth holding on to! Yes, the difference in wood glue is so often the fail point with a laser, and most non-laser suppliers haven’t the foggiest. Do you mind sharing who/where your supplier is? Maybe other folks on here can reward their customer service!
I looks like the problem with the plywood has/will be resolved. My wood supplier, Conejo Hardwoods, took a look at the stack of Baltic Birch plywood they had recently received. Turns out only the first few sheets apparently had been made using the exterior grade glue. They gave me a sheet which likely as not was made with interior grade glue since there are no visible lines between the plies. A quick test run worked out great. Monday it’s back to getting my full order.
Wow, that’s awesome you were able to get that squared away so quick.
Actual Baltic Birch from the Baltic has very strict rules for how it is made as the highest grades are used in aircraft. Which are generally used outdoors. The regular 4x8 birch has no such rules. My first buy of non PG wood was just such material, and it still stands as the the worst I have seen.
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