Thansk again Chaniarts, for this suggestion. (P&M)
It tuns out what I ended up buying had the 3M logo on the backing tape, but it only had tape on 1 side. And it was vinyl tape, not anything like waxed paper, though I think I also read somewhere else about waxed paper. It was indeed harder to use with only one side lined, but I think all in all it came out well, and I think I was able to avoid sticking the untaped side to anything, for the most part, or at least it was still sticky when I pulled small parts up (with the backing tape) to move them.
A reason my window might have been harder to do than yours is that the vinyl went under the window, so I had to put the tape in place while I was in the back seat. Of course the center of the window is easy, but I tried to run the tape as far to the side as it would go. I cut 36" pieces.
Another problem is that my window is rounded at the upper corners and the tape is straight!! I could have cut several pieces and put them at different angles, but I didn't. For various reasons, I'm the only one who will notice this.
I did note that if I touched the surface 3 or 4 times, it wasn't sticky anymore, and that was with clean hands. Maybe I should have washed them immediately before to get rid of my fingerprints. I also am undecided if the 4910 is as sticky as adhesive mouse traps. One would think they would be the same stuff or stickier.
I have some left, that I think will have a lot of uses. Right now, I bought a ScanGauge II, and there is no good place to mount the little thing, but though Imay use the Velcro for a while, I think I will switch to this tape for a firmer and more professional-looking install.
Back to the window, it originally had an overlap of one inch, but without tugging the overlap was at most between 1/2 and 3/4. Since the window was held up in other ways, and wasn't sagging even without any support from the top, I saw no point to tugging on the cloth/vinyl at the top, and making separation more likely.
So I figured it woull overlap between 1/2 and 3/4. That would leave some of the tape showing if I bought 3/4 inch tape, and even more if I bought 1 inch tape.
I ended up putting two widths of one inch tape on the vinyl, facing up, and one 1-inch width of tape on the top of the glass, facing up.
Then I cut a strip of black convertible top material^^^ 36" by 3.5".
After attaching the vinyl curtain from the bottom, as originally planned, I think put that 3.5 inch strip of convertible top on from the top, even at the bottom with the bottom of the VHB tape on the window. I also stuck the strip to the VHB tape that was stuck to the vinyl curtain. The width of the three pieces of VHB tape was about 2.5 inches, but I made the strip 3.5 inches so it went all the way up between the convertible top and the rear window curtain.
So the window is sandwiched in between two layers of vinyl, one that is the curtain and one that is taped firmly to the curtain.
It looks good, but I haven't lowered the top yet. Too cold (58) and cloudy to want to. But Monday will be sunny they say and in the 60's.
^^^The convertible top material came from my '73 Buick Centurion convertible, that I had from about 1980 to 1987. I had a new top put on about 1982, and I might have replaced the original top, so the fabric I used this week was 38 years old. And still in excellent condition. I could tell that I'd cut out a similar piece before, but I forget for what.
This is why I try never to throw away anything. If I needed a strip of convertible top material, they dont' sell 4 inches anywhere. Or even a yard at a fabirc store. I'd have to go to a top shop and beg.
At the same vendor, your link went to 36 yard rolls. but the catalog I used and the link I found with it only went to 72 yard rolls. How strange!
I didn't actually use 4622, because iirc it is white. I used 4910, which is clear. It is also 40 mils thick and the store webpage I ended up using gave a strenth measurement, and it was 10 or 15% more adhesive than the 20 mils.
I ended up buying from Grainger.com, which has a lot of stores around here, Maryland, but also ships all over the world, I think. I think you have to have a business or a friend with one.
They had 5, 15, and 36 yards, but maybe not in every kind and widtht!
It was only 20 dollars for 5 years of 1/2", 30 for 3/4", and 40 for 1". I have about 2 yards left over.
I'm not sure even the 3M site mentioned all these sizes.
There were the two guys on ebay who said they took big rolls and made small affordable rolls, and that implied the tape had backing on both sides. But my 5 yard roll didn't. So I guess there are a lot of ways this stuff is packaged.
Thanks a lot,