Remove Acrylic/VHB Window

[fritzdfk]

I have a couple of windows on a glassed plywood hull attached with VHB tape and a little caulk around the edges, no fasteners. The acrylic is 1/4" and there is a slight curve fore and aft. The windows are about 2' long. They were installed 4 years ago and have developed small vertical cracks along the edge top and bottom, they are not leaking. Of course this is disappointing and up till now have often admired how good they seemed. I don't know if this is common for this type of installation or there is something about my particular situation. I am in Southeast Alaska so there is a lot of temperature variation and I understand that acrylic expands and contracts with temperature. Anyway it looks like sometime in the not too distant future I will have to remove and replace and I can't quite figure out how to remove them. I have imagined running a thin blade all round maybe even an electric knife. Anyone have any experience with removal?

[Nightsky]

A Fein or Multi tool will make short work of it.

[hellosailor]

fritz-
3M suggested a citrus or orange "solvent" cleaner to attack the VHB tape. Assuming it is genuine VHB or something very similar, you can try that, and of course letting it work in for a few hours. If the tape is pulled slowly, it stretches and peels like a very stubborn Command strip. Pull harder it is just stretches and snaps.
You can call 3M's toll-free numbers to see if this is still their current thinking, or if they've found a better solution by now.

VHB is supposed to be compatible with plastic glazing, although any petrochemicals attack the plastics. It is also supposed to have enough flex so that it will allow the plastics to expand and contract. Possibly this was not a UV-resistant grade of plastic, or the added stress from curving the material was too much for it?