My grandson's favorite color is green, so I printed a catapult toy for him that I had previously printed in red. The parts were brittle and weak, with little or no bond between the layers. Printing with monoprice black resulted in the same quality as the original red part. The green was also weak on a thin walled box that I had previously printed in red. I tried experimenting with the extruder temperature, but was not able to get acceptable results.