Print Bed Experiments

So I thought I would report my finders thus far with my tweaked print bed. I've been using the 3m green painters tape (2060) on my print bed after I destroyed the first buildtak as the prints stuck too well. The green tape has been working well with a wipe down of methethylated spirits between prints. If I don't scrap/scratch it getting the print off then it lasts a good while - at least 12 prints.

However I was finding that the acrylic build sheet was not very flat and seems to be changing shape over time with calibrations/prizing prints off etc etc, I have a few beds from reprappro and the most used one even shows signs of stress fractures. So looking for a solution I tried glass. I had the local glass company cut me a 170mm circle of float glass that's stuck to the standard bed with double sided carpet tape and then a layer green painters tape applied.

So far its working very well, the prints are much smoother ( I'm getting a lot less bed movement for big prints) and calibrations can be a lot quicker (although my dive height is still set quite high because of bed swapping).

I went for 4mm glass as they company said the 3mm wasn't flat (green house/horticultural glass I think.) and I guessed the the 2mm was too thin, but at the price I may get some 2mm just to try too. Want to maximize the build height

Downsides are the probe points occasionally show a break and require the plate to me bounced on the spring in each corner.

With the cheap filament I'm using I put the first layer down at 220c and then drop to about 200c

The glass was very expensive at £5.

The glass will be adding weight to to bed which will be making the springs a lot more sensitive, try putting some wads of paper down the three spring retaining holes to increase the spring compression and the upward force on the plate....stiffer springs would be a better solution but that is not the easiest to do.

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RepRapPro Mendel 3 Tricolour
RepRapPro Fisher
-Carbon Arms
-Easy adjust Carriage+effector
-axis stiffness mods
HE3D -600 delta
-Duet 0.8.5
-PanelDue
-DC42 Height probe
-RobotDigg metal components
Simplyfy3D
RS Design Spark CAD

I'm not sure increasing the spring compression alone would be enough as the probe rods on mine have a tendency to spread, I'd probably need to add something to keep them together too.