This will burn for a few hours, relatively clean. This is a very simple design that leaves much to be improved. Most TLUD designs will include a means for preheating secondary air. You can’t see it here, but we added another section of stove pipe to facilitate a stronger draft. Definitely use the driest wood chips you can, anything less is likely to smoke a lot. Still, this burns very hot, so be careful, and obviously don’t burn this without some supervision.
You’ll know when it’s ready to quench because the temperature will drop, it will be difficult to keep from smoking, and the smoke will have that familiar charcoal smell.