Re: Spray-in liner on hardtop?
Gotcha covered guys:
Use 1/2" closed cell neoprene foam. Use a very high quality contact cement. Go to the local supply house for auto uphostlery and buy some yards of the seat cover material or something else you like. Or use feed sacks or don't use any cloth at all. I used Jeep uphostlery material to match my Sahara seats and cut the neoprene foam to size first and then the cloth to a size about 4" larger each way. You can put the cloth on the foam first or foam on the hardtop first. It doesn't matter. If you want a perfect match to all of the surfaces and contours of the interior of the hardtop, then you are looking for a long hard pain in the nether world. My suggestion is to cut the foam to the large dimension of the flat part of the top and glue it in place with the outer 2" left free of adhesive on the top. Put adhesive on the foam, though. Cover the foam on the exposed side with adhesive and since the cloth (also covered with adhesive) is larger than the foam, you just tuck the edges in under the foam edges and presto you have a nice pad that looks factory! I have done two of these and wouln't have a hardtop without it. The drumming sounds on the highway are gone forever. Road noise in general is greatly diminished. The cold is held at bay in the dead middle of the Montana winter and the most surprising part is the major change (reduction) in the heat gain in summer. It kinda puzzled me on this at first until it occurred to me that the material of the top is composed of a lot of glass which is transparent to most heat radiation. We are definitly cooler in the summer. It is a worthwhile investment in time and money. I think I have probably $100 - $120 in it. By the way, I also got some extra foam and put a pad in the rear floor pan and on top of both fender wells. This is just loose under the carpet, though. It also was an improvment over the factory cheesy way of ignoring the heat coming from the underside.
The first key to the whole thing is to use closed cell foam. Open cell will absorb and retain all manner of liquids none of which will do your Jeep parts any good. The other key is to use a good quality CONTACT cement. Wal-Mart stuff won't do. The thermal loads and shocks on a headliner are horrific. (Just ask GM. They haven't been able to get a headliner to stay in a vehicle for more than 7 or 8 years in about 25 years.) As I said, I've done two of them and have six years on them now with nary a problem.