Found some 8101/2 canvas blanks. Have to pull the crumb tray because it is 1/2 inch think. Cannot get the settings right to print on the canvas. Any suggestions on setting or placing the canvas without the crumb tray will be appreciated.
If it is a half-inch and not 0.501+ you can use the crumb tray.
If you do not use the crumb tray you need to support it below with one inch plus and use the Set Focus in either case. If it is 0.5 or a hair less on the crumb tray using Set Focus will tell you so.
If the top of the canvas is below the height of the crumb tray (1.50 inches) it is too low and Set Focus will tell you that also and even if you somehow forced it the focus will be off and the image blurry.
The surface to be engraved must be between 1.5" and 2" from the floor of the Glowforge. If your primed canvas is engraving poorly, it could be a focus problem. Remove the honeycomb tray and elevate your material so that it is in the proper focus range.
There are lots of examples of canvas engraving here in the forum. Search results for 'canvas' - Glowforge Owners Forum
Just in case this is helpful: