I did something really, really stupid with my BuildTak surface. When lubricating my magnetic joints in order to get my printer working again, I got a tiny spray of PTFE lube on the BuildTak. Don’t do this at home children! I now have a totally non-stickTeflon build surface. Nothing is shifting it - PTFE is invulnerable to 99% of solvents. Warning in the manual please?
Would also be good if Velleman/Whadda added some PTFE lube into their starter kits - because so many people find out while building that it’s required but not included