Basically spent from 10 am until 3:30 pm (with only minor breaks now and then) struggling with the install of the wire grid from the stick-on kit. I have not completed the connection to power/ground and, of course, have not tested anything yet.
First, the summary conclusions:
1. DO NOT, I repeat, DO NOT try to install the grid lines individually - especially if the window glass is curved as it is on my 240s. I tried everything in my power to get the new wires to follow the old ones in the glass. This is simply impossible to achieve since the new grid wires cannot really be made to follow the way the original lines travel (discussed above). My results are less than ideal and in some places down right awful.
2. There isn't single step in the process that is forgiving. You basically get one chance and one chance only to do something and you must be spot on the very first time. I went slowly - measured twice and cut once and all that. But still managed to get caught off-guard at some points.
3. Baby its hot inside! The instructions insist that you have many hours of 60 degree+ weather to do the install. I would say we hit 70 today but it was only 62-3 when I started. Working in the rear seat, close quarters and all got quite hot - even after I threw a white towel over the window to reduce both heat and glare.
4. Oh my aching knees and back! Good thing I removed the right side front seat from my 242 as I must have had to get in and out of the car about 100 times while doing this. My rear seat has gotten more use today than in the last 20 years for sure. And despite the padding of that seat, it still is quite unpleasant on the old knees. That padding is made for our hindquarters, not our knees.
5. Would I do this again (even if it does work - and I have my doubts)? I certainly don't think so. Installing via the multi-line sheets MIGHT be better than one at a time. But I am unconvinced the results would be that much better. It is true that some of my most serious difficulties resulted from trying to match the original grid lines. This takes far more time in the stick-on process but also in having to custom cut the buss bar components to fit the result. If the results were better, it might be worth it. But they weren't.
Now some details:
1. The release paper used for the inside surface of the grid wires does not provide any visibility. It is too opaque. And so you simply cannot even see the existing grid lines enough to follow them with any accuracy. I say this even after going the extra mile to put 1/8 masking tape over each line in an effort to make it stand out/show through the paper.
2. The release paper has no ability to flex or place the grid wires in any but straight lines. Just forget about anything else. I did not try, as some suggested, to make cuts in the paper to facilitate this. The process is just too difficult to consider doing this as you are sticking things on. And you are severely time limited. From the time you use the special moist cloth to wipe down the window and then dry it off, you have only 30 minutes to complete installing the grid. The instructions were not specific and I was only able to install the horizontal grid wires in about this time. I decided not to sweat the time limit on the buss bars. It would have been impossible to get it ALL done within the time limit even if I had NOT done this line by line.
3. The release paper itself is made sticky. I get this as necessary to make it all work. But from my standpoint, the degree of stickiness is about 3-5 times more than it needs to be. And this makes removing it much more difficult that it should be. I would snip the paper with my surgical snips in the middle of the window and start to pull/tear from there. In many cases the release paper simply would not release nicely and left bits of itself that I had to go back and address. Thankfully, the wires, once stuck to the window, seemed to hold tenaciously enough that the release process worked without pulling them off the glass.
So all in all, the interior release paper is a problem.
4. The buss bars are actually comprised of multiple pieces and need to follow a specific pattern with gaps between them as they cover the grid wires. I am not sure I understand why this is so given that the original defroster just had straight bars with no gaps at all. But the instructions are VERY SPECIFIC. I understand that had I not tried to follow the original grid lines, the pieces included in the kit would have been sized correctly for the grid supplied and most of the pain associated with the buss bars dramatically reduced. But I didn't and so I had to custom cut every piece of the brass strips to follow the pattern. Overall, this makes the buss bars shorter and so the adhesive strip which holds them to the window and the cover pieces must also be custom cut. And at least in my case, this had to be done by sight in the back seat as nothing turned out consistently space to allow for computations and cutting in my shop.
5.The adhesive strips that adhere the buss bars to the window have adhesive on both sides. One is covered with release paper very similar to that used on the grid wires. The other side says 3M on it and is red plastic of some sort. The instructions do not say which side to use where. The 3M side is super hard to start peeling back. I could NOT have done it with the strip in place on the window. I had to fiddle with it using a tweezers in the shop under a magnifier. So I decide to get that side started in the shop, go out to the car, peel off the rest of the red plastic, and adhere that side to the window. I hope that was not an error. But there was nothing in the instructions to clarify it. With the release paper side on the interior, I was able to work with sizing the buss bar strips of brass without fear of getting it stuck in the process by accident. And I could pull back the paper only as far as I needed for the section of brass I was working on at the moment.
6. Above I discussed the "tip" to NOT touch the brass strips of the buss bar and how I had done that to a significant degree prior to the install while trying to make a full scale mock up of the layout. Thankfully, Jeff told me not to sweat that too much and to wipe the brass down with the included wet wipe cloth if needed. Well, there is no way in the world one could manage all the custom fitting and cutting that was required without touching all over the brass strips. So I am glad Jeff chimed in. Again, much of this was due to my decision to try and match the existing grid rather than use the kit out of the box.
Here are photos taken today.
You can easily see my general failure to closely match the lines of the existing grid. You can see from the inside how opaque the release paper is and this makes orienting and following the grid lines near impossible - even it the original lines were straight (and they sadly are far from that).
What you cannot see is that it is nearly impossible to avoid kinks in the wires. After putting them down, I tried to smooth them best I could using an old credit card like a putty knife. You cannot over do it as that might break the wire and then you are totally toast. So all you can do is try to minimize these. There is one case that is severely kinked with the wire a bit twisted so you can see a bit of the copper side from the outside. That should NOT be the case at all. But again, the opacity of the release paper makes it impossible to see from the inside what is going on so this was not really apparent until the release paper had been removed. And by that time, the stuff is down and there is nothing you can do.
So, will this work at all once power and ground is supplied? Will it work, but not well due to the minor and major kinks in the grid wires? Will the contacts achieved to the buss bars be good enough after all that handling and cleaning? Will this work but the kinks and uneven spacing cause bad heating characteristics resulting in a shattered window? Only time will tell!