Hi! I have been printing really nice prints with my PulseXE. Almost always printing with PA-CF. Good adhesion with Elmers Purple glue stick. No warping. Parts fitting good so prints exact as the 3d model size-wise. But I have had 3 days of disastrous prints. 3 large long prints. 14hrs + prints. The problem is they look great but are extremely brittle. I was printing great with Fiber Force Nyl Force Carbon Fiber. Not super smooth but Strong parts and no warping. Then I ran out of this filament but I had an old big spool of Matterhackers pro series carbon fiber (previously printing great with this one). It had been opened and not used for a while and so I kept it inside the print enclosure while printing other stuff and the printer has been printing continuously for days so I think it is very dry inside. Anyhow, I printed a long print and it looks super nice. It released easily from the bed the next day but it was super brittle as I was examining it. The print broke easy. I received 2 new spools of colorfabb low warp Na-CF. As they were in a vacuum package I decided to try them so I swapped out the large spool of pro series to the colorfabb. I printed a 17hrs print and the next day it also looked super smooth and nice. As I grabbed it from the print bed I literally exploded like uncooked pasta in my hand. Super brittle and very weak. The print was an iteration of a model I printed last week so almost the same in size and thickness of walls etc and that old one is crazy strong. Then I tested all my old stuff and they are very strong. I printed one more time with the new colorfabb low warp and the same result, very brittle. More brittle than any plastic. Worse than PLA or whatever. As for the pro series Carbon fiber, It could be that it was unused for a long time. That I understand, but the same issue with new vacuum-sealed colorfabb. Is it just bad luck that 2 brands in a row are very brittle or is it something else? This is the first time I have had problems with PA-CF being brittle. Does anyone have experience with this with brand new filament? Why would brand new vacum sealed filament be brittle? Because it is 2 different brands but the same issue in a row, I am wondering if it isn't the filament but something with settings or printer? I am using recommended setting of the manufacturer of colorfabb low warp setings. For the matter hackers pro series carbon fiber filament I used Nylon X settings.