For the bed surface, only need a few molecules thick of ABS. For adhesion, we are looking at surface properties rather than bulk properties. Try 5mm of filament in 20ml of acetone: it looks just like acetone but leaves a thin film behind. If you heat it before it dries, it will bubble. Otherwise, you should not be able to see it. Similarly with PVA glue, just a few drops of wood glue in 20ml water works a treat (but takes ages to dry, so a bit of heat helps - but not too much). If I am in a hurry, then I use a glue-stick!! If you want to protect surface of bed, stick a layer of painter's tape (the blue one seems best). Maybe that is enough to get sticking, but the above two tricks have always go me over the line. 

Just had a thought: try lifting head well clear of bed and doing an extrusion so you get a 20 cm strand out of nozzle without pulling it thin. Check the diameter, it should be about the same as nozzle size (or just a bit bigger). Oh, it is a 0.4mm nozzle and not a really fine one? If nozzle is partially blocked, just got to remove it and clean it out - easier said than done, I'm afraid to say.

Dan, I am surprised at <I fought a hell of a long time with my DIY Prusa i3. Nothing sticks to any bed, and I blame the nozzle.> Just a couple of 'tricks' just in case you have not tried them already.

For printing ABS, dissolve some scrap ABS in acetone and paint it on the cold bed and allow to dry. For PLA, a common adhesive to try is PVA: a glue-stick rubbed on makes a bit of a mess, but PLA sticks. Finally, ensure nozzle has a gap to extrude the plastic into, but not too far away that you just get a loose strand of extruded filament. Just adjust bed height so that plastic gets squashed a bit onto bed. Oh yes, feel free to experiment with bed temperatures. For small prints, a cold bed can work (maybe), but for bigger prints, definitely need to keep the plastic sticky enough to hold on until it chills.

abs slurry is a mess to clean up, I abandoned it years ago. Gap is jus the enough for a piece of paper to slip through. I also recently added a bed probe in case the bed wasn't curved, and I tried a box around the whole thing to control heat. None have helped :