For a very very rough first approximation, charring is proportional to the amount of time the beam spends in one place. So inversely proportional to speed. (I think that this happens because a very short exposure still vaporizes the top layer, but doesn’t give time for heat to propagated down to lower layers that can burn without being vaporized. Sorta. Kinda.)
My notebook has some numbers I don’t trust, but for the cleaning pass I would start with full power as fast as you can go and then maybe back down the speed if needed (or power if you’re cutting too deep).
Yes, but as more material is removed, the difference between the lightest (highest) and darkest (deepest) becomes more pronounced, particularly with additional passes - the focus on the deepest part would need to adjust to be optimal I think.
The Proofgrade setting incorporates two passes for the best detail in thick material. We still have lots more autofocus work to come, but it’s getting better.
I’ve used a soft toothbrush for cleaning up fine detail on wood items, and using either rubbing alcohol or acetone won’t raise the grain or cause the finished piece to warp.
