Im having trouble leveling my bed

Try getting some glass. My bed was warped in a way similar to yours. Initially I just leveled it for the center because thats where it prints, but with larger prints the edges would curl up. The glass solved that problem and it also just seems to stick better than the bed anyway with some hair spray. I got mine from the local hardware store and they cut down a few pieces for me for 9 bucks.

I think the bed is prone to warping during use due to it's relatively thin gauge to start with, as well as the heating element being only in the center.  Milling it flat may help initially, but may also make the situation worse going forward.  I would try the glass route.  You will be assured of a flat surface.

You compensate for that using the Z-stop screw adjustment on the back inside of the case, about midway on the left-hand side of the bed carriage.  If your glass is, say, 2mm, Lower the bed 3mm using the manual control on Repetier, and then lower the screw to hit the microswitch again.  Home the Z-axis and readjust the screw up a bit at a time and keep homing until you're close enough to begin to re-level using the bed leveling screws.

So I have my glass too but I haven't tried it yet. What temps should I set the bed to? I tried getting it to 90c+, but it barely gets up to 80. Is that enough for parts to stick?

the bed is a pain.

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!

Glass is the way to go. I tried one print on the kapton then switched to glass and no going back.
I got a 12" x 30" x 3/32 piece of glass and glass cutter kit (cutter, oil, greese pencil) from Home Depot (like $15 total) and cut the glass myself. Use the oil, straight edge, and make one pass with the cutter. Hold on edge of bench or table and snaps right off. Can even use sand paper to smooth edges. I used my electric disc sander with 80 grit! For real it worked.

Smitty

Mine is warped near the edges especially in the back. It is like 15 mil lower than near the screws.

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! 

Also have problems, having had my SD2 for almost a year now and printing 4-8 hours every day. Few days ago I noticed  some problems with the straightness of the bed, and with dial indicator noticed that there is over 1mm (!) of warp in my alu bed... Going to get some glass tomorrow, and hoping to find some binder clips, PITA to get them here...

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...