High resilience foam questions

I am sure some answers are already here, but I have read and read and just get confused.

I am thinking of building an all foam mattress, and why is it most tops seem to be memory foam or latex ? I was thinking a ( true ) high resilience would make a good top ? that being said, I am a back sleeper 180lbs slim build. my thinking was an 6" HD support core of mid 2’s in density and then 4" of HR 2.8-3 lb medium ILD 28 on top. Maybe 3" ILD 28 and 1" ILD 24 ???

Questions:
Would this be a good choice ?
Support core ILD ?
If latex is better choice on top I suppose 3" ?

Would thinner layers ( and different ILD’s ) getting to my 10" high be better than 2 ?

My finding of the HR foam was at foamonline:

Weight:

3.0 lb. per cubic ft.
Quality:excellent
Longevity:approx. 12 years
Density lbs/cu. ft.: Minimum 2.50
ILD/50 sq. in. @25%(4 in.)
35% max.
Support Factor: 2.5
Hysterisis Loss @25% 35% max.
Tear Strength, lbs/linear in. 1.50 PLI min.
Tensile Strength, lbs/sq. in. 12.0 PSI min.
Elongation, 150% min.
Resilience, 50% min.
Compression set,
90%, 22 hrs., 158° F
Less than 10%

Hi David2469,

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 (and option #1 and #2 as well) so that you have more 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).

Memory foam and latex are both popular materials in comfort layers because they are a preference for many people and also because they are more heavily advertised as more “premium” materials and more widely available but there are also many other types of comfort materials that some people may prefer.

Unfortunately I can’t help with the “comfort” or “suitability” questions because only you can feel what you feel on a mattress and there are too many unknowns, variables, and personal preferences and sensitivities involved for anyone to be able to predict whether a specific mattress or combination of layers will be a good match for you in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) based on either specs (yours or a mattress) or "theory at a distance (see mattress firmness/comfort levels in post #2 here). Your own careful testing or personal sleeping experience will always be the most reliable way to know whether any combination of materials is a good match for you in terms of PPP and even the most knowledgeable mattress designers with years of experience with different combinations of materials will often be surprised at the difference between how a mattress was “supposed” to feel “in theory” and how it actually ends up feeling in “real life”.

Just as one example of some of the complexity that can be involved … post #4 here has more information about the different specs that can affect the firmness/softness of a mattress outside of just ILD (which by itself may be as misleading as it is helpful) and some of the specs that can affect the feel and performance of different materials or a mattress that uses them in post #2 here. There is more information about the different “types” of firmness/softness that different people may be more or less sensitive to in post #15 here.

There is also more information about primary or “deep” support and secondary or “surface” support and their relationship to firmness and pressure relief and the “roles” of different layers in a mattress in post #2 here and in post #4 here that may also be helpful in deciding on layering choices but once again you will only know whether any combination works well for you when you sleep on it.

Outside of “comfort” issues and the "suitability of the materials in terms of PPP … they would all be durable materials and certainly wouldn’t be a weak link in any mattress.

There are many different types of foam materials and not all polyfoam that is 2.5 lbs is HR polyfoam and there are many people that may prefer higher density polyfoams that are less resilient (see post #2 here for some examples). The choice of materials (or combinations of materials and components) in a mattress create an almost “infinite” range of different “feels” and are always a personal preference.

You will need a great deal of experience and trial and error to find the combination of layers that is the best “match” for you and one of the most important parts of your choices will be the options you have after a purchase to either return or exchange your layers so that there is less risk involved in purchasing layers that don’t work as well in your design as you hoped for.

The most effective approach with a DIY design is to either use a reference point of a mattress that you know is a good match for you in terms of PPP and where all the materials and layers that it uses are known and available to you or alternatively to use a “bottom up” approach where you begin with purchasing the support layers and then decide on each additional layer above it based on your actual sleeping experienceion your previous layers (see post #2 here).

You are dealing with some very complex specs and you will need some personal experience on different combinations of materials to be able to “translate” them into something that is meaningful to you based on actual experience instead of “theory”

Phoenix

Thank you, I will look over that. With all that being said, I have a Boyd Natural Flex 920 . My first is an all foam mattress and about a year is all that foam seems to be good for. I took it apart only to find ( IT IS NOT MADE AS IT SAID ) it has 1" on bottom then two 4" layers and 2" on top. It was supposed to have ( 3 layers total with 3" on top )

I removed the top and put 4" super soft on the bottom and flipped it the encasement. Thinking I needed softer. foambymail super soft broke down in one week. softer where butt was. I flipped it over again and am sleeping on the 4" whatever that is under thier so called engineered latex. it was for awhile but now hurting again LOL. So all in all I figured I could put quality foam in place of this crap.

Hi David2469,

The layers that the Natural Flex 920 is “supposed” to have are listed here.

If the layers in your mattress are different from this I would consider calling either your retailer and/or Boyd to find out why (or whether you received the correct mattress). I would also be aware that all the layers of this mattress are polyfoam including the “engineered latex” (see post #11 here) and with a mattress like this I would always make sure that you know the density of all the polyfoam layers before a purchase so you can make sure that there are no obvious weak links in the mattress and make more meaningful comparisons to other mattresses.

I would also 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 reliable supplier.

Phoenix