I'm sure you're all familiar with good old contact cement. So far, this was the one product I had found that would actually hold things to the fiberglass. You may remember that the Loc-tite Ultra held to some extent, but not long term. (Other than using fiberglass resin, but that won't work to adhere large flat surfaces.)
While we're here, let me show you this brush I bought. It has silicone bristles, just like the silicone barbeque sauce brushes, only shorter and more rows of them.
No one, not even the guy who's worked at Lowe's for 17 years (forget the kids who've been there 5 minutes and don't know what you are even asking for), could tell me if you could use it with contact cement. It says it's for wood glues. Well, it was only $3, so I gave it a try. Answer- it works great. You just let the glue dry on the brush and then peel the dry glue off. It won't stick to the brush.
Now back to the scheduled program. The contact cement is here to do battle with the product recommended by Scamp. This is Helmistik 1685. It's a Canadian product and very hard to find in the U.S., but I found a dealer who could sell it to me. (The Canadian companies won't ship it to the U.S.- at least not to an end user.). This is a latex-based spray, but let me tell you that except for the consistency and faint odor it has nothing in common with liquid latex. I've used liquid latex for stage makeup purposes quite a lot, so I know how that looks, feels, and smells.
I had pretty much decided, based on price, that I was going to glue the underneath layer of foam to the fiberglass with the Weldwood contact cement. I knew it worked. Well, that's what I thought I knew. But as I was taking down the rest of the ceiling insulation, I learned that some of the places where I'd used it to glue white foam to the fiberglass had let loose. So... good, but not 100%. But, I'd been using the open quart I had to begin putting the underneath layer of new foam against the fiberglass. I finished that, but hadn't opened that full gallon yet.
Yesterday, I tried gluing two pieces of the polyethylene foam (the white) together with the Helmistik. It's also a contact cement, so you spray both surfaces, let it dry for about 10 minutes and then press them together. I checked to see if you really could reposition the pieces before they adhere for good. Yes, you can do that. That's going to be really important for putting the finish layer back up.
Today, I experimented with the other options. I wanted to know if you could actually use it on the green foam- polystyrene. You can't use the regular contact cement on that. It's like pouring gasoline in a styrofoam cup. The foam just disintegrates. So I sprayed a small piece of the green foam. Where I used a light coat, it got a little dimply. Where I hit it heavier, it became shrunken or pitted- but it didn't really disintegrate. You can see the deeper damage in front of the white below. Well, that was interesing.
So, I decided to see if it would bond anyway. I prepped a small piece of the white foam and pressed them together. Voila! I believe this has actually formed a chemical bond. These are unlikely to separate without ripping one of the products.
I decided to see how well each of these would stick to the fiberglass using the Helmistik. Just to experiment, but not use a lot of product, I did one tiny piece of each color and sprayed both the fiberglass and the foams.
You can see that they are stuck, but what you can't tell from the picture is how well they are stuck. Trying not to exaggerate, I'm going to say that the bonds appear to be about three times better than the contact cement. I think the only way I'm going to remove these samples from the fiberglass is with the oscillating saw. I'm certain that if I just pull them down, the foam pieces are going to tear, being less strong than the actual bond.
Well! This has certainly changed my persepective. I think I have to return that unopened gallon of stinky contact cement. That stuff has serious fume issues for days after you use it, and you need to apply it with good ventilation. The Helmistik hardly smells at all. The Helmistik bonds better, and it's easier and faster to use. It will cost a little more, but not THAT much more. It will take a few days to get more cans of it here. The one thing I can not find anywhere is figures for square feet of coverage. Hopefully, the man I talked to when I ordered this first can might know something. I'll be calling him tomorrow. I'd like to order all the rest of what I need at one time. The shipping price is outrageous because it's considered some sort of hazardous product. (Believe me, I read all the fine print. This is way less hazardous than the familiar contact cement, but I'm sure there's a government regulation involved somewhere...)
This is like the miracle glue that I knew must exist somewhere!
And, I re-attached the finish layer on this one tiny section near the door. I just wanted to know how easy it's going to be to spray the first layer that's attached overhead and then put on the single sheet. Of course, this was the small piece, but it was easy peasy. I held a piece of paper up to mask the edges where I was spraying. There was no dripping. I repositioned the finish piece once, and it looks great. Of course, I knew it would look OK, but I'm also confident that it's going to stay up there this time.
The other thing I did was sand off some of that epoxy paint and fiberglass these two little braces to the frame again. Hopefully, they will stay put this time.
Believe it or not, just that, plus some more prep work with taking down the old ceiling took me three hours. Part of that was finding tools and products that have been put away for two years, but that time all counts.
Other than that, I edited in the morning.