How to remove 3M VHB tape?

I have a client who is trying to figure out how to fix a large mirror display for a trade show booth.

There is a 4' x 8' plate glass mirror bonded to an aluminum sheet using VHB tape. The frame got hit by a forklift and the glass is now being flexed out

1/4" in the middle. Not good.

I figured out how to fix the frame, but it would require removing the mirror. Any ideas?

Reply to
Ernie Leimkuhler
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Get the solvent from 3M.

Reply to

Perhaps you can thread some dental floss or thin piano wire between the joint and cut through the tape. Some heat from a heat gun might help also.

Try the dental floss first as it is less likely to scratch the coating on the back of the mirror.

Reply to
Roger Shoaf

Spectra fishing line is considerably stronger than steel (or dental floss) of same diameter.

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Reply to
Don Foreman

Spectra (high strength polyethylene) is strong in tensile strength, but has a VERY low melting point. If you saw with it, it will probably break.

I would consider using Kevlar* cord. You can get Kevlar braided line as used for kite lines. It will work better as a saw than twisted lines.

In fact, it works so well as a saw that it is considered too dangerous to use when flying near other people. Don't try to hold it with your bare hands; use sticks or rings to hold the ends. Don't leave it attached to anything where someone could get caught in a loop and cut themselves. It will go right to the bone.

If you have to knot it, sleeve it with hollow braided polyester (Dacron) line before tying. A long narrow loop of fine music wire will push through the hollow-braid polyester to pull the Kevlar through. Visit a kite shop, and you will find sleeving needles (the wire loop), Kevlar cord, and polyester sleeving material.

Cruder but easier: cut a couple 3/4 x 3/4 sticks and wrap the cord around one several times and clamp or screw the other tightly to it to make a handle.

(*Kevlar is a trademark of DuPont. They write me to complain every time I fail to mention that.)

-- --Pete "Peter W. Meek"

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Reply to
Peter W. Meek

Braided Wire, Hit a glass shop and ask them for some of the braided wire they use to remove auto glass. It will cut through the tape like a hot knife. Or use a heat gun to melt the adhesive. But that could also damage the mirror. If the aluminum isn't that that thick you might try a good auto body suction cup and pull it back.

Reply to
Steve W.
3M has a PDF document on removal. Did a search for "3M VHB tape" and got it directly from 3M's site. It's all mechanical systems to air hammer a skinny chisel in between the parts and a buffing wheel to remove the residue, though.

I recall having to disassemble things like this before, and it was a royal pain. Started with a bunch (a bunch!) of thin wedges and a heat gun. Starting at one corner and working your way carefully to minimize preload on the glass, slip the wedges in as the adhesive warms up and softens. You might be able to take advantage of the preload already in the glass, but there'll be a point where it pops and the glass could break. Maybe putting shot bags on the glass would help. The tape won't be all over the place, just applied in strips, so trying to keep the wedges where the adhesive isn't will keep them from gumming up with adhesive.

Reply to
carl mciver

If you use the kevlar line with a bit of epoxy bonded glass dust on it it will saw very well.


Reply to
Doug Schultz

I happen to know a guy who used to work with adhesives at 3M. He knows the Tech service guy who does VHB, Who either knows how to remove the stuff or can find out. Want me to forward your post to him?

Chris Don't force it - Use a bigger hammer.

Reply to
Chris Cox

Reply to
Charles Spitzer

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