On Lulzbot’s website, when printing with nylon, they recommend to use a “glue stick (such as UHU® brand)”. I had never attempted to print with nylon and I recently ordered some (bridge and alloy 910) when I also ordered a LulzBot Mini Flexystruder Tool Head v2, which came with a standard UHU glue stick. So when printing with the easier of the nylons, bridge nylon, I applied a little bit of this glue stick and my small test print came unstuck pretty fast. I tried sanding my PEI bed, applying way more glue, adjusting settings, etc.–no luck. So I did some research and nylon likes to stick to PVA based glues when printing. UHU glue sticks have very low PVA percentage apparently, so I bought a glue stick with a reportedly much higher PVA (Elmer’s washable glue stick) and my bridge nylon prints stuck perfectly first try. So did my alloy 910, the most tricky nylon to print with I hear.
Just a heads up for anyone struggling to print nylon: regular washable Elmer’s Glue/Glue Stick (school glue) worked MUCH better for me than the brand Lulzbot sells and recommends. Lulzbot should probably change their product description to be more specific on what type of glue stick to use, especially since the one they recommend doesn’t work very well!