OH, about ABS&acetone... Used it myself until I accidently bought a can of xylen instead of acetone... For some reason I get better prints with ABS&xylen than with ABS&acetone, no idea why...

Dynamechgt, instead of altering the gauge holder. just print a new gauge back for your dial indicator without the mounting tab.  That is what I did to mount a guage on my SD3.

Thats a good idea!  Although, I also need to slightly alter the overall design for hole size and pinch points regarding the wood strip at the extruder - I'll probably keep the tab (mostly for alignment) and just extend the length of the piece.

I'll look at it a little closer when I get home this evening - I'd like to keep the indicator shaft as close to the extruder as possible to maximize measurable bed space.

Ive even thought about putting an extension on the indicator shaft and then have the body of the indicator positioned more on top of the extruder than out in front.

Edit:    why?    .....because I'm a dork and want to try to measure the whole bed! 

@ danny -
Excellent heat map of the bed heights!  I was thinking about doing something similar after I alter the gauge mount to work with my gauge (holder on back of gauge gets in the way).  What did you use to make the map?  I was probably going to run a matlab script on a spreadsheet of the measurements.

Smitty

I used the spacer method, (proper metal gauges) when I first got the printer, I measured over the entire range of the printer, and set it quite good, there was about 0.05mm deflection in the bed, (some places the 0.3mm gauge was fine, some spots were a little low and the 0.35mm gauge fitted.

after a while using the printer, the bed warped to be practically unusable. the low spot stopped being 0.05mm low and started being in excess of 0.1mm, then there were high spots as well as low spots. I used a dial guage to map the bed, and produced the following heat map:

blue is low going through green yellow orange red as it get higher, you can see that one corner is very high, while the corners bow extra low. but importantly you can see that the bed has like a spine running diagonally from the lower right to the centre of the bed.
total deflection on this picture is -0.08mm to +0.43 (0.5mm total deflection) - a real problem when you're trying to set the bed 0.3mm from the nozzle!
(this map is produced after I already tried bending the plate to straighten it, - which did have some success.)

long story short, either get some thicker aluminium plate and put that on top of the bed, or get a sheet of glass.
the glass is recommended since it can be thinner than the plate would have to be in order to hopefully stay true, and given that it's made by floating on a bath of molten tin is about as flat as flat can be!

A case will help keep the ambient temp up. If you didn't order one (I didn't because I thought it was for cosmetics), you can make one from a standard 12"x12" shipping box. Just assemble the box and cut off the flaps on the open end. Then, cut off one of the sides. This will be the side that goes towards the back. Cut one adjacent edge from one of the sides to make a large "door" with a hinge at the top (or side if you want). Then you can use some blue painters tape or other tape to secure it to the frame.

thanks guys