Acetone and Kapton Questions

[Busybotz]

What exactly does acetone do to kapton to make it sticky to ABS? Does it keep the tape clean, or does the acetone itself make the kapton more receptive to ABS?

Also when should kapton be replaced? Only when it is damaged, or are its properties diminished with each use? 

I am new to Makerbotting, and after 25 or so prints on a Replicator I am learning the black of art of getting prints to stick. I do level the build platform often, to the point where a slip of paper receives friction from the nozzle, similar feel to using a feeler gauge on a car engine. 

[AKron]

I can't answer your question since I'm day #2 with the Replicator. I
(almost) always clean the build plate with fresh acetone, and wipe it
with whatever color I'm using dissolved in acetone so that it leaves a
haze on the Kapton tape. My tape has all sorts of blemishes on it
already from it getting pulled up when I remove a part, but it's
printing a fairly big piece now without a raft, and there's no sign of
warping. My acetone comes from, ah, ACE hardware in a metal can. I've
heard some people using fingernail polish remover, but all I've ever
seen in my life had additives to keep your nails from drying out too
much, and we can't have that now!
I don't think I like rafts too much. It leaves a crummy surface on the
bottom. It's almost as if Skeinforge knows there's a raft, and just
spits out whatever crap it wants to for the first layer. I'm sure
that's just my imagination though. Also, rafts take a long time, and I
hate throwing plastic away like that!

[Michael Cook]

I've had a Thing-o-Matic for a little over a year, and I've been using
acetone on my kapton basically the whole time.

Acetone will dissolve ABS, which is why you can use it to make a model
shiny or to glue two pieces of ABS together. From my experience, it
seems to simply liquify the ABS molecules on the tape so they can be
wiped off by whatever you are applying the acetone with. Those little
bits of ABS (along with dust, skin oil, etc) are what your print would
end up sticking to which may cause your print to lift off the
platform.

I clean my tape before every printing session (to get dirt and such
off), but I'll only clean between prints if I'm having sticking
trouble or expect that the print may be difficult to keep on the
platform (say something with small contact points or that leans). For
prints that have a large contact area with the plate, I'm careful to
*not* clean the platform too much, so it won't be too hard to get the
item off.

I use the same piece of tape for weeks on end. The only reason I ever
replace it is because I end up putting big marks in it or ripping up a
little piece trying to remove a print that's really stuck too tight.
As long as the surface is good, it just keeps working.

Getting things to stick is a little tricky. As long as your tape is
relatively clean, height is probably the most important factor. Too
high and nothing sticks, too low and (besides possible extruder
damage) things stick so well they are nearly impossible to get off.

[Erwin Ried]

I prefer to use just water, seems to work better for me. Try going with 10ºC extra for the platform. I use jetty's firmware to make offset adjustment over Z axis when I see the first layer not printing well (too squishy or a bit lifted on corners), full calibration script adds a lot of fuzzyness/magic to the process, I am not sure if the replicator had options to set offset values, but without calibration or acetone I lastly get like 99% reliability, even when my printer is not in the same floor, I just press print and wait for the "beeps" to go to retrieve the object.