adding middle layers of foam

[phoenix]

Hi dastur,

I know this is a complex design. I can experiment until I find the right setup. But experimenting has already cost several thousands and is still be a work in progress. Latex can add thousands more to the cost of experimenting and still be a work in progress. I think I may be able to find a conventional foam solution that works well without breaking the bank. But then what?

For me the answer would be then I would sleep on it. If the materials you use are high quality and durable materials that don’t have a smell that you are sensitive to and the mattress is a good match for you in terms of PPP then it would be reasonable to expect that you will sleep well on it for a decade or so.

I would also read read this post and this post and this topic (about their polyfoam and sources) and this post (presumably from a past employee) before buying anything from FBM or considering them as a supplier.

Hypothetical examples: 3" of LUX feels like 3" 44 ILD blended Dunlop, or 2" of HR36 feels like 1" of 32 ILD natural Talalay.

Of course these are hypothetical examples only. Question is, are there any such guidelines? I understand that the ILD numbers don’t necessarily correlate well.

No … there aren’t any such guidelines and the only way to do this is with the type of personal experience and knowledge that manufacturers gain over the years that comes with trying hundreds of different combinations of specific materials and components. There are just too many versions of each type of foam or components and too many variables involved and anyone that has designed mattresses will tell you that they are often surprised at the difference between what a mattress was “supposed to feel like” based on the specs and materials they used and what it actually felt like when they put the materials together and tested it in “real life”.

ILD is only one of many specs that can affect the feel and performance of a mattress that don’t correlate well between different materials or even between different versions of the same material. If you are attracted to the idea of designing and building your own mattress out of separate components and a separate cover then the first place I would start is by reading option 3 in post #15 here and the posts it links to so that you have realistic expectations and that you are comfortable with the learning curve, uncertainty, trial and error, or in some cases the higher costs that may be involved in the DIY process. While it can certainly be a rewarding project … the best approach to a DIY mattress is a “spirit of adventure” where what you learn and the satisfaction that comes from the process itself is more important than any cost savings you may realize (which may or may not happen).

I would also base your design on a mattress that you have tested and confirmed is a good match for you in terms of PPP (the simpler the design the better) and where the same materials are available as separate components or alternatively I would take a “bottom up” approach and start with the support layers and then gradually and incrementally choose softer layers to add on top based on your experience on your previous combination that keeps moving you gradually closer and closer with smaller and smaller incremental changes until you reach your ideal design or at least are “close enough” that any further additions wouldn’t be worth the small improvement that you may achieve.

Phoenix