The Problem:
The rear window in the convertible roof becomes detached from the canvas.
Disclaimer:
I offer these instructions to be helpful, as I have benefited from others who have posted instructions. I don't guarantee the accuracy of these instructions, nor your results should you choose to follow them. Personal or property injury could result from following these instructions. Follow the instructions from the glue and primer vendor. Be careful. And if you don't feel comfortable doing this kind of work, please hire a trained professional to do your repair work.
Time required:
This should take about 2-3 hours of work and at least a day for the glue to cure, depending on temperature and humidity.
Tools & materials required:
* Razor scraper.
* A piece of sandpaper. (Maybe 60-100 grit or so. Used is fine.)
* Utility knife.
* A fine point (preferably) dry-erase marker.
* 9” stick, preferably about 1” thick. (See photos.)
* Packing tape.
* A couple of rags or towels.
* A roll of paper towels.
* 3M Glass Primer- product #08682 (30ml) or #08681 (125ml). 30ml is more than enough. Available online.
* 3M Windo-Weld adhesive 10.5 oz. tube [#08609] . Available online.
* A caulking gun.
* Several sets of latex gloves.
* About 8 full sized towels (like you would use to take a shower), rolled up tight as shown in photos.
* A drop cloth or two (to protect your seats from glue).
* A flashlight, portable electric lantern, or utility light, so that you can see well and work inside the dark window-well.
* Optionally, but I'd recommend, an assistant for about 5 minutes during final gluing and taping stage.
How to fix it:
NOTE:
These instructions (and photos) are based on my 1996 Cavalier convertible coupe but are probably largely applicable to most convertibles of any make or model where the glass is glued to the canvas.
After gluing my window, it felt very secure and I feel confident about it holding long term. However, I am posting these instructions just one week after gluing. I'll try to remember to check-in every few months to let you know if it continues to hold. I'll check-in right away and let you know (by posting below) if it fails.
BACKGROUND:
The bottom edge and the lower half of the side edges of my rear window became detached. I did a lot of research on how to fix it. Many people had posted online that they had tried many different types of glue, but the general consensus was that standard glues (epoxy, gorilla glue, etc.) don't hold
in the long run. There are glues that stick to canvas, and there glues that stick to glass, but when gluing glass to canvas you need a specialized primer and glue like the 3M products listed above. (There may be other brands or suitable glues. I don't know.) I could not find the aforementioned 3M adhesive products in auto stores, hardware stores, or retail stores like Walmart, so I had to order them online. They were easy to find online, simply by searching for the product name and number listed above. I got the primer and glue shipped to my house for about $30. The smallest sizes available were at least 10 times more than I needed, and apparently the glue & primer have a very short shelf-life so feel free to get the smallest size available. The instructions for the glue and primer can be found on the 3M website.
STEP BY STEP INSTRUCTIONS:
1) Unlatch the roof, raise it about 6", and prop it up above the windshield with something (like a bunched up towel) as show in the photo. This relieves pressure from the back window.
2) Detach the interior plug for the window defroster if that will be in the way of where you need to glue.
3) Using a razor scraper, scrape all of the old glue from the areas of the window that have come detached.
4) Use sandpaper to rough up the shiny-smooth portions of the canvas (inside & outside pieces) that will attach to the glass. I'm not 100% sure that this step is necessary, but it makes sense since it give the canvas some tooth for the glue to attach.
3) With a damp rag and a dry towel, clean and dry the entire window (on both sides), the surrounding canvas, and the trunk lid. You'll need that all to be cleaned and dry to the you can properly glue the window and tack it into place with tape.
4) Cut a stick to about 8-9 inches. I cut a 45 degree angle on a 1" square bar of scrap wood, 9 inches long. The angled end then slides snugly behind the seatback and props up the back window. Fold over a small piece of packing tape so that it's sticky on both sides, and put it on one end (the blunt end) of the stick. This will keep the stick from sliding across the inside of the window. Then place the stick as shown (behind the center of the seatback) to prop up the window. Be sure to place the rod on the window
between the defroster lines so that you don't accidentally take off any defroster paint. (See photos.)
5) Place a drop cloth on the back seat, over the seatback, and if you're really fussy, in the window well, just in case you drip some (black) primer, (black) glue, or drop the magic marker.
6) Now that the window is propped up, test-fit the canvas on both sides, and tape it in place with a few vertically placed strips of packing tape such that there are no wrinkles in the canvas.
7) Mark the window along the canvas line on both sides with a magic marker so that you'll know where to paint the primer.
8) Throw out the old tape that you used for the test fit.
9) Put on some disposable latex gloves. I'd actually recommend putting on double layers of gloves so that, if necessary, you can quickly strip off the top pair if they get messed up while you're gluing. You don't want to get the primer or glue on the canvas, car body, or interior fabric, and I'd say that the most likely way that you'll do that is by touching something with a dirty glove. The workable time of the glue is 15 minutes so you won't have much time to get the job done.
10) Paint the 3M glass primer onto the window (both sides) using the magic marker line as your guide. FYI: The primer is black. The instructions say to use a wool dauber, but I just used a small disposable paint brush. You will need to throw the paint brush away so make sure that it's disposable. Allow the primer to dry at least 10 minutes (per the instructions on the label).
11) Remove the pull-tab from the back of the 3M Windo-Weld glue canister and place it into a caulking gun. FYI: The glue is black.
12) Cut the tip of the 3M Windo-Weld glue canister at an angle as described in the directions for that product.
13) The instructions on the glue say that you just need to lay a bead of glue along the window and then attach the canvas. But I wanted to be certain to get the maximum possible surface contact so I also used my double-glove-covered index finger to rub glue across the entire portion of the exterior side of the window to be glued, as well as rubbing the glue into the entire part of the exterior canvas to be glued. Then I quickly threw away that top layer glove, leaving me with a clean glove beneath. I'm not sure that's all necessary, but that's what I did, and I'd do it again. Don't use so much glue that it will squeeze out onto the window and make a mess. A thin (say 1mm) layer on both the glass and the canvas should do the trick.
14) With clean latex gloves on your hand, attach the exterior-side canvas to the window, and tape it securely into place with some packing tape, as shown in the pictures, at first with some long vertical strips, and then with some horizontal strips running the length of the canvas. Press the canvas and the tape snugly in place, using the primer, glue, as your guideline. The glue is very tacky almost immediately, so the canvas sticks almost immediately, but is workable for a few minute or two. You can do this alone, but you may want to enlist an assistant for the gluing and taping portion. It's pretty hard to rip off new tape with latex gloves. It's OK if some glue squeezes out onto the window because you can scrape it off later. It's not OK if glue gets on the canvas.
15) With clean latex gloves, repeat the gluing and taping process from the previous step for the interior side of the window and the interior canvas.
16) Use some rolled up towels (as shown in the photos) to hold the interior canvas against the window while the glue dries. (Otherwise the portion of the canvas which is not next to the tape, will tend to fall away from the window.
17) Let the glue set according to the curing times listed in the instructions. The curing times vary greatly (from about 1 hour to 100 hours) depending on temperature and humidity. (The more humid, the faster it cures since it's water activated.) I let mine cure for about 3 days in arid California, just to be sure.
18) After the glue dries, remove the tape, the towels, and the prop-up stick.
19) If there is excess glue on the window (which is likely), use a razor scraper or utility knife, running the knife along the edge of the canvas, inside and outside, (perpendicular to the window) to cut a line across the glue, so that when you scrape off the glue, it will peel away from the window at the canvas line. Be careful not to cut the canvas.
20) Using a razor scraper to scrape any excess glue from the window, inside and out. Be careful not to scrape off the defroster paint line on the interior.
21) Remove the towel that is propping up the roof above the windshield, and reattach the defroster plugs if you've disconnected them.
22) Pray that it holds and close the roof. Good luck!
Photos are at the following link:
http://picasaweb.google.com/104746918913021986185/CavalierConvertibleRearWindowReattachment?feat=directlink
