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I spray window cleaner on the glass, then apply the tape, and use credit card to move all bubbles to the sides and out. Let it dry (you could try heating the bed to evaporate all remaining liquid). This results in a perfectly applied Kapton tape.

You can also find some instructional videos on youtube.

So what's the trick to apply Kapton tape without bubbles? I bought an eight inch wide roll for the press, but what a pain to apply!

Use two inch wide and apply strips next to each other smoothing as you lay them. Just use it in the area that the print will be in. or use Elmers purple glue stick. It works far better than Kapton and is much easier to apply.