Lemme jump to the punchline: don't use Kapton tape anymore!
We've just wrapped up a nice group buy thing-a-ma-jig over on the MakerBot Operators' Google Group. Hammerhead suggested posting the file so others could follow suit, and so participants could fly the flag.
This is a plate of glass that goes directly over the aluminum heated build platform on a Replicator 1:
- 3.3mm borosilicate glass
- 230mm x 150mm, +/-0.030" tolerance
- edges seamed for safety
I made the buy from Industrial Glass Technologies in North Carolina. There was a $6.21 per plate charge, and a $50 minimum order. We cleared that pretty handily :-)
Once you have your plate, however you come by it, clip it to the top of the aluminum platform with either medium-small binder clips or printed clips (I modeled some that I'm using, but I'm not in love with them: http://www.thingiverse.com/thing:35687). I'm looking into better options for holding the plate on/down.
Note that some people leave a layer of Kapton there between the aluminum and glass. I'm not sure if that helps or hinders things in any way. It's an insulator, but probably not very significant. I prefer the glass-on-aluminum approach.
You'll also need to trick your Z axis limit switch: http://www.thingiverse.com/thing:35530
I've been using an HBP temp of 115Â°C, but I just applied thermal interface grease between my heaterplate and aluminum, so that may allow me to reduce the setpoint. Untested so far.
I've been having the best luck so far using hairspray on top of the glass to improve ABS stick to it. I use it liberally. I apply it outside the Replicator: it can't be good for all the moving bits in there. It's also important to raise the platform a half a hair (literally) to increase first layer "smoosh." From what I've heard (haven't yet tried), PLA is a gimme, even without hairspray.
Hairspray brands: I've only tried two;
1.) Suave Super-something-or-other: worked okay, smelled terrible (pump bottle)
2.) Fructis Extreme Control Anti-Humidity (with natural bamboo extract): dubbed by Hammerhead as "Nuclear Hold," it actually held so well that it allowed his ABS print to tear up a chunk of glass as it warped. Upon hearing that I rushed out to get some :-) Smells fruity. holds well. Reported to work with taulman's Nylon 618 too.
Others report success with Aquanet. I have a bottle but haven't tried it yet.
I use my little razor handle (http://www.thingiverse.com/thing:34481) to get stuff off. You could also cool the plate rapidly under water or in the freezer; the plastic and glass cool at very different rates.