Tried to take the LokBuild off the glass - it ain't cummin'!!  So I'll put up with it for now and order another borosilicate glass plate.  May try PEI.

PETG is working well enough - particularly for smaller but higher prints.

One thing I want this Mini printer for is the Escape Wheel for a pendulum clock (long case).  Previous attempts at printing this have resulted in insufficiently accurate results and the print did not work well enough.  I'm hoping I can produce an accurate enough print with this printer - it does seem better than any other I have had.  I am starting with PETG to assess the accuracy and if adequate I plan to use Nylon.  So Nylon will be the next filament type I shall try.

Escape Wheel has printed well and measures up perfectly (as near as I can tell).

Now printing in Nylon - looking alright so far but only on layer 3 so far.  The printing is set fairly slow for better results and 0.25mm layer height with 0.4mm nozzle.  The results with PETG were good so I'm hopeful that the Nylon version will also be... Oops, spoke too soon - print has detached from bed may need higher temperature of closer nozzle.  I'll try the latter first as it's easy.

No joy there.  Took the nozzle to almost touching the bed (0.1mm) so I'm increasing the bed temperature from 80°C to 100°C and trying again.

Stayed on a bit longer but still came off.  Trying 120°C bed temperature.

Nope - trying 140°C bed temperature.  The bed surface must be cooler than the thermistor in the heater pad with glass and LokBuild on top.  Maybe hotter filament might help - I'll try that next - currently 260°C.  Could go to 270°C or maybe 280°C.

No good - can't use Nylon on LokBuild  - sticks at first then starts curling off at around layer 3 or 4 even with bed at 140°C and hotend at 280°C

Looks like interchangeable beds are required for different filament types.  Though I did get Nylon to stick to glass on my Titan printer.  Most seem to stick to glass even if with a bit of difficulty.  Recommended surface for Nylon is Kapton film which I do have in a 200mm wide roll.

Ordered a new glass plate :- Signstek 3D Printer MK2 MK3 Heated Bed Borosilicate Glass Plate Panel 213*200*3mm  Due to arrive tomorrow.

Tried printing PLA on the LokBuild - 200°C hotend and 50°C bed.  Stuck firm in centre but curled up at edge.

Are you printing with a brim? I tend to have a 5 to 8mm brim on everything these days - stops any curling.

Not this time as it was the escape wheel and also LokBuild is not supposed to need a brim.  TBH though, LokBuild has more problems than glass for most materials, I've found.  And it's stuck so well to the glass plate that it's impossible to remove without risking breaking the glass.  I have printed Nylon on borosilicate glass plate without a brim and it stuck well enough.  I prefer to print gears and suchlike without brim because of the trouble of cutting/filing the brim off between the teeth. 

Maybe LokBuild is fine for special cases where there is a large overhang and small area on the bed but I've got used to designing my prints not to be like that and to have as much contact with the bed as possible.  If I were to stick with the present 12v 220W heater pad, which is not stuck to the glass, I could swap plates.  It's held against the glass with 12mm thick polyurethane foam. The 240v 450W heater pad I was planning to use has a self-adhesive top surface for sticking to the bed plate.

I'm going to try PEI.  UEETEK PEI Sheet 8" x 8" 1 mm 3D Printer Build Surface Ultem 1000 (With Back Glue)

This can be stuck to the glass plate or not - double sided adhesive sheet is supplied to be used if desired.  I'm going to try it without.  It will be held by the 3D printed bed frame which I'm going to arrange to be easily removed from the Z carriage.  ATM it's just sitting on it but I'm going to add quick release clips.

Glass plate arrived this morning.

Plate unpacked, copper foil strips added (for the Z probe to sense) and fitted into frame then frame placed over bed heater and polyurethane foam in position.

PLA printing perfectly on the glass plate.  Stuck when hot and released when cooled down   This is the base of a moon globe that I plane to use for my long case clock.

PETG is printing well and sticking nicely to the glass bed and releases when cool.

I'm currently printing this Glowing Moon  from Thingiverse - top part for my long case clock moon phase dial.  Except that I've cut off just under half of the back of the globe as that part is never seen.  A hemispherical cover printed in opaque black PETG or ABS will cover part of the moon globe to show the phase. 

Been going over 2 hours now and looking good.  Probably something like 7 hours to go but as the print gets further up there will be less to do per layer so will get quicker.  Current estimate is based on what has been, I believe.  It doesn't look like Slic3r gives an estimate of total printing time.

Over 4 hours now and still fine.  ETA looks like around 1am tomorrow morning but we'll see.  Now seeing some definite surface structure.

Bridged the gap and no drooping.  Overhang Threshold was set at 95% and shows how well PETG copes with overhangs.  This is the base of the globe - bottom when installed in the clock.

At the two thirds point now (it says).  Still going fine