I still haven't had to level the bed at all since my last post
At this rate, I think I'll leave my BLTouch off for now.
Got some ERYONE black PLA off of Amazon, I read mixed reviews but mainly good. I've had more problems getting the settings right for this than for the cheap no name stuff I was using.
Not going to attempt to put photos in line, will put them all at the end.
There's two temp towers. First with combing on, second with combing off, second was much much better. The PLA says it's temp range is 200 to 220, but the temp tower was best at about 185.
Then I tried playing with retraction settings. Printed a load of 5 min tests at various speeds and length, not only did they all string, they also pulled away at the top quite a bit. I read an article somewhere on the net where someone had similar problems and they put 0.2mm in both the "outer wall wipe distance" and the "Infill Wipe distance". This improved things considerably , I've attached two string tests, one with wipe, one with the same retraction settings but without wipe.
I still had to increase travel speed from 150 to 200 to get reasonable results.
I then did another ton of tests, the best I could find was Retraction distance 5, Retraction speed 40, travel speed 200 (and the 0.2mm on the wipes). OK not too much hassle to do, but surely I must be doing this the hard way? Surely most people don't end up printing about 50 string tests
Going back to my previous post, I've attached a bed temp photo. With the bed at 60, it's 60 right until the last few mm at the back where it drops to 57c. However at the front, it drops right down to 32 degrees at the edge and the middle of the E on the word Creality is only 37
(sorry the 37 doesn't show up very well in red in the photo). The left hand edge of the bed is almost as bad as the front while the right hand edge is similar to the back.