Doesn't any one know about this stuff?
Some updates from a post I put on another site:
"The temper for pillows and bedtops is really to soft for automotive use. The best prices I have found so far are at
http://www.mcmaster.com/. The temper they sell goes under the trade name of Confor. Currently, the hot ticket (at least for someone my size, 5'10 170) seems to be a thin layer of Yellow (CF40) or non-technical foam with a IFD of <15 (multiply mcmaster's compression rating of psi @ 25% by 50 to come up with a approximate IFD), over a layer of pink (cf42) over blue (cf45) over non tecnical foam of about 40 IFD. This seat should not bottom out and be comfortable. Wrap the whole thing in Dacron. I would go with 1/2", 1", 1" and 2" thicknesses respectively. The non-technical foam should have a desnity between 2.5 and 4 pcf (pounds per cubic foot).
To put some of these to real world numbers for Confor (just the one peice of confor, nothing else), for a seat pad 3-4" thick you should use cf42(pink) for 115 pound person, cf45(blue) for 170 pound person and cf47(green) for a 200+ pound person or a 170 pound person in hot and humid conditions. This will not bottom out, offer excellent dampning and shock absorption (you won't feel like you are setting on a mini-trampoline. The approximate IFD for these is 30, 35, 60+ respectively.
This is for the seat CUSHION ONLY. The number for the back are greatly reduced since the amount of weight supported is greatly reduced. Additional perspective is that the IFD for pillows and bed tops is in the 10-15 IFD range so you can clearly see just how thick the pad would have to be to support the weight!
Remember, this stuff is temperature and humidity sensitve. The warmer and "wetter" it is the more compliant it is. 50 to 120 is considered it normal range. Above that it is VERY soft, below that it is very firm.
So no someone go out and try it! I have to many projects going as it is to get to it before next winter!
Rick"