| i have a sleepez bed that I keep trying to soften by adding more layers of foam in the case. So I now have 4.5 layers in a case meant for 3 layers. The case still zips, but I wonder if I am compressing the foam so much that it is affecting the feel. I have talalay latex, which always felt springy to me, but I am wondering if this made it more springy? Or if this is bad for the foam? |
|
WARNING: This is going to be a long post and probably of interest only to those who want to know more "why" than "what" :) COMFORT There are basically 3 factors that determine the comfort of a foam layer. These are how much weight it takes to compress a foam to 25% (ILD or IFD which are basically the same), how much more weight it takes to compress a foam to 65% (called sag factor, comfort factor, or compression modulus), and the point elasticity of that foam (there is no common measurement for this that I know of although it's talked about in various places). ILD @ 25% (and at 5-10%) is a big part of what determines the "feel" or "hand" of a layer but it says little by itself how soft the foam is in actual use unless you happen to be one of those that sinks into it exactly 25% and the odds of this are low. If you sink into a layer less than this it will feel softer. If you sink into it deeper it will feel firmer. This is why weight plays a major role in how soft or firm a foam "feels". This feel is not the same as pressure relief which is determined more by the next 2 factors. In other words, ILD is how soft a foam feels "with a little bit of compression". Sag factor (the ratio between the weight needed to compress a foam to 25% and 65%), which could also be called "progressive resistance", plays a major role in comfort and pressure relief ... at least as much as ILD. The reason for this is it is a big part of what determines how far you will sink into a layer. With a deeper cradle, you have more surface contact between your body and the foam and this distributes your weight and creates pressure relief and comfort. The more evenly a layer distributes your weight, the "softer" it feels. Once you have sunk in to the point that the maximum surface area of your body is in contact with the foam and the largest possible surface area is bearing a proportionate part of your weight, then sinking in further has no benefit in terms of pressure relief. Talalay lets you sink in further than Dunlop and since most people sink in further than 25% into a top layer, Talalay of the same ILD will usually form a better cradle and feel softer than Dunlop. Talalay can also be made softer than Dunlop because it uses less foam in it's manufacture (It's less dense than Dunlop) and it is easier to control the firmness. I should also mention here that this lower density does not mean that it is less durable because of several internal factors in the foam itself which is outside of the scope of this post. So "sag factor" is how soft a foam feels with "more compression". In very general (and not quite accurate) terms, cheap soft polyfoams have a sag factor of @ 1.5 or less. HD polyfoams have a sag factor @ 2.0. HR polyfoams have a sag factor of around 2.5 (although some are around 3). Talalay latex is also @3 so slightly higher than HR polyfoam. "Normal" Dunlop goes up to around 4. Custom formulations of Dunlop can go as high as 5. Custom formulations are determined by the raw materials used, compounds added, size, shape, and depth of the pincores, vulcanization methods and other factors. Point elasticity, determines how exactly or perfectly the foam contours to your body. This also plays a major role in pressure distribution. The more exactly a foam conforms to your body, the more contact area there is between the foam and your body to distribute your weight and the better the pressure relief. In the same way, an innerspring with 2000 individual springs is more "point elastic" than an innerspring with 500 individual springs or an innerspring with 2000 springs that don't act individually. Latex in general ... and in particular NR or natural latex has very good point elasticity ... better than other types of foam (and similar to memory foam except memory foam is more point "responsive" since it isn't very elastic at all). Point elasticity (or point responsiveness) is about how small an area of a layer can act individually without affecting the surrounding area. Hysteresis (time delay in a foam's return) along with elasticity are also important parts of perceived comfort or "feel" as they create resilience or "pushback" and a feeling of "liveliness" in a mattress. I'm including it here because in general terms it is about how much energy is lost between a foams compression and it's return and there is a "sweet spot" that contributes to a perception of comfort and ease of movement on a mattress. High hysteresis is part of the reason that memory foam provides such poor support. SUPPORT Support is determined by a combination of ILD (initial compression of a layer), Sag factor (deeper compression of a layer), and Resilience or "pushback" (made up of hysterisis and elasticity). The two parts of support involve "stopping the sinking in" at the correct point (using layer thickness, ILD, and sag factor) and "pushing back and holding up" the more recessed areas of the body that don't "sink in" as much (using depth of cradle and resilience). A higher sag factor which stops the heavier parts from sinking in as much is why Dunlop is considered to be "more supportive" than talalay although this is only one of the parts of what makes up support. I'm including this here because "too much" or "too little" of some of the comfort factors can lead to poor support and this is where the "tradeoffs" and choices in layering are important in mattress construction. TRADEOFFS Too little ILD, especially in combination with too low a sag factor or too much thickness in comfort layers, can result in pressure relief but they allow you to sink into a layer or "go through" a layer too easily and lead to hammocking. This is typical of the thick layers of low sag factor polyfoams that are commonly used in the top of many mattresses. Low ILD's in the comfort layers with higher resiliency and sag factors (as in low ILD Talalay) and "reasonable" thickness don't usually have this problem. Too little ILD in middle and lower layers can often allow for too much sinking in to the mattress and loss of support regardless of sag factor (this is what I believe was happening to you with 2 mediums). Too much resilience (very low hysteresis along with high elasticity) can also "push back" too much in certain cases where the cradle is too deep and lead to perceptual discomfort for some people. This can be especially true if you sink too far into a layer with high resilience in certain zoning schemes and the wrong parts of the body (like the lumbar) are bearing too much weight. This is also another reason that the thickness of the comfort layers are important and too thick can lead to "too much" support or "upwards pressure" on the lumbar area for some people. Too high an ILD, especially in combination with a high sag factor in the comfort layers (like firmer Dunlop) can also lead to less pressure relief and discomfort as well as poor support of the recessed areas of the body. Higher ILD with slightly lower sag factors (than Dunlop) can provide a deeper cradle and more pressure relief as well as better "pushback" support to the recessed areas of the body and is part of the reason Talalay works so well in a comfort layer. These are some of the "tradeoffs" involved in choices of between different materials, layer thicknesses, and construction styles (progressive or differential) in different layering schemes. Specific to your comments or questions Dunlop has a "naturally higher" sag factor than Talalay because the rubber particles tend to settle in manufacturing which means that it gets firmer faster with deeper compression than Talalay. It also uses more rubber in its construction (is denser) which also contributes to a higher sag factor. This allows a Dunlop layer with the same ILD (@ 25%) to feel almost the same as Talalay if you sink into it 25% but get firmer and provide better deep support (the kind that stops you from sinking in) if you sink into it deeper than 25%. This natural quality of Dunlop can either be "enhanced" in production through the use of different depths and shapes of pincores (and in other ways) or it can be reduced in the same way. Different Dunlops in other words will have different sag factors but in general they will all be higher than Talalay. Even those with "compensating" production methods will generally have a firmer side and softer side but some will have less difference than others. In a single core mattress that is made of only one thicker single layer, then the greater sag factor of Dunlop with a slightly lower ILD could be better because it lets the top part of the layer (say first 2 or 3") act like softer talalay but the bottom part of the layer would act like firmer Talalay. It's like "built in layering". If a Dunlop 6" core had a softer layer over it then this would make less difference in terms of needing a "soft upper part" of a layer and then a firmer Dunlop would be more appropriate. I don't know the details of exactly how the Englander Dunlop is made but it would likely have at least some difference between sides. The difference may have been "offset" to some degree in production so it may be less than other types of Dunlop latex and even if it wasn't the sides may not have enough difference that flipping it would present a major problem unless someone was really sensitive. To someone who would feel comfortable laying directly on Dunlop as a comfort layer (it doesn't come as soft as Talalay), it probably wouldn't make much difference. Even if both sides were exactly the same though, it would still have a higher sag factor than Talalay and may be more suitable as a "single core" mattress. Thicker cores also have a higher sag factor than 2 cores of half the thickness because of the "order of compression" of foam layers and what I am going to call a "boundary effect" which are both way more than I want to get into in this post (I made that term up because I don't know what the actual name of it is). Enough to say that they "act softer" and "compress differently". If there was a difference in density from top to bottom of a Dunlop 6" core (which there probably is to differing degrees), then the increased sag factor of a single layer core over Talalay or over 2 half cores would be even more pronounced. I doubt that turning over the 3" layers would make a big enough difference to feel that much. The 4" topper over a firm Dunlop may very well give you the "OMI feel" with better support. In general the thinner the comfort layer that gives you the best pressure relief the better. The OMI 25 would feel and act a little softer because of the convolute. I think the firmness of your 5" comfort layer is coming from the 2" FBM which I don't think is soft at all based on all your feedback. 5" of soft would be too much and you would certainly not be feeling it as "too firm" if the whole 5" was soft ... especially after what you were feeling in your field testing. As far as the foam in the closet, I doubt that you've destroyed or really degraded it. Maybe shortened it's life a little bit. If it looks and feels OK it probably is. I think that your experience with our testing ... taking into account the differences in your support layers and in using "unknown" layers is pretty consistent with what you felt in your field testing. I think trying to test a layer just for support without the comfort layers on top would give a distorted picture as the comfort layers are part of the support "equation" and how far you sank into a support layer can be changed with comfort layers and different approaches. I think you could only get a true picture with both together. Comfort layers are more suitable to "testing by themselves". In general ... considering all your feedback ... I think your tendency is to sink in too far in specific places (pelvic area) and not enough in others (shoulders) so in terms of "non zoned layering" I think that a nice soft and thick enough comfort layer (probably in the range of 20 - 24 give or take and around 3.5" - 4") over a really firm support layer is looking like the best combination (outside of double zoning if it's needed). I think that "stopping the sinking in" of your hips is probably easier (with firm support layers) than "letting your shoulders sink in enough" (soft and thick enough Talalay) and the wide difference in needs between the shoulder part and the pelvic part makes a differential approach more suitable for you. A progressive approach that let your shoulders sink in enough using part of a softer (medium) middle layer mat let your hips sink in too far into that layer (like they are with your medium Dunlops) but this would depend to some degree on it's sag factor and what was under it. If you wanted to test this I would try a 3" and a 4" soft Talalay topper over the firmest Dunlop they had (either Natura or Englander) and see how your shoulders felt with each. If the 3" is enough to let your shoulders sink in and you didn't feel pressure on shoulders or hips, then it would be better than 4 in terms of support and "stopping your hips" but it may be "just short". Beyone that zoning (softer shoulder firmer pelvic) would be the way to go. I know I'm going to get some "flack" from "certain quarters" for how technical and long this post is ... but you asked ... and I did my best to answer  . After all you are an engineer and it is your thread lol. Phoenix This message was modified Dec 28, 2010 by Phoenix
|
|
Phoenix Thanks again for the long post. Amazingly informative and helpful (to me at least)! But the more I understand about this, the less I think a sleepez scheme is going to work for me. There are so many variables, and they are so hard to predict in combination. Say I go back to the store and determine I like the OMI topper over the firm Englander core. The OMI topper is a sophisticated blend of materials that I can't reproduce with say just 3" of 20 ILD latex. And the Englander core is a solid 6" which you say is going to act and feel very different than two 3" firm pieces. So I can sink another $1000 or more into trying to get this right (6" firm dunlop and 1-2" soft talalay and maybe dormier or natura wool topper) or I can find something I love for probably $2k and just buy it. Guess which way I am leaning right now? |
|
IMO ... 2 x 3" pieces of firmer dunlop in your type of construction would be similar to a single 6" piece ... especially with a layer of soft on top which makes the higher sag factor of a softer medium or soft dunlop single core (softer on top firmer on botttom) are less important. The higher sag factor is most important in a single core with nothing on top so you can have a "reasonably" soft ILD (say 26) Dunlop layer and still have firm support in a single 6" layer although it does have other benefits as well particularly in "progressive" layerings. The OMI convolute is not so hard to "duplicate" I did it (at least in my feel) with 3" 22 ILD with no convoluting. Of course my weight distribution is different from yours (and I do have other "stuff" over the 3") but the idea is it's not so hard to "duplicate". Basically what "convoluting" is doing is giving the layer a higher sag factor (softer with shallow compression and firmer with deeper compression). An inch of slightly firmer talalay under 3" or an inch of softer talalay over 3" would act in a similar way and you may not even need the extra inch with a medium Dunlop under. The biggest danger you face IMO is the wide differential in the needs of your shoulder vs the needs of your hips and without zoning you would need a softer comfort layer to accomodate your shoulders and let them sink in enough with a firm support to stop your hips. Given what you have if you were to go in that direction and also given the results of your testing and especially your floor testing ... I have a feeling that 3" extra firm dunlop under medium dunlop under 3" soft talalay wouldn't be that far off. The 3" Talalay would be a little too thin but the top inch or so of the medium dunlop would add thickness to your comfort layer and then the sag factor of the medium dunlop along with the very firm underneath could give you good support. This is using a "bit" of progressive layering but would still be primarily differential. You also have another option that only involves getting a 3" very firm Dunlop which is using your medium Talalay in the lower 2/3 of your mattress and the softer Talalay in the upper 1/3 of your mattress (2 zone) and this zoned 3" comfort layer over medium and very firm Dunlop could work better than any single zone system IMO. I would certainly spend time with the "progressive approach" thinner talalay over the Dunlop if you felt it was worth it but I have my doubts it would be thick/soft enough for your shoulders. I guess that $2000 would buy a lot of mattress but for the risk of a single firm Dunlop you would already seem to have what you need to get things to work. If you can get the firm Dunlop with the ability to return it then you would have little to lose and I think it may be another "surprise" in terms of how close it could be ... with or without zoning. You could also buy a quiltable latex cover here if you wanted to replace yours and you wanted to go in the direction of a little more "comfort" latex in a quilting (and didn't mind losing the wool in the quilting) but I would wait till you tested the xfirm Dunlop layering (if you decide to go in that direction) to make sure your experience indicated you needed it. Phoenix PS: 3" Medium over 3" firm Dunlop would act in a similar way in terms of "progressive support" to a single 6" layer of high sag factor medium ILD Dunlop. This message was modified Dec 28, 2010 by Phoenix
|
|
The OMI convolute is not so hard to "duplicate" I did it (at least in my feel) with 3" 22 ILD with no convoluting (I do have other "stuff" over the 3") but the idea is it's not so hard to "duplicate". Basically what "convoluting" is doing is giving the layer a higher sag factor (softer with shallow compression and firmer with deeper compression). An inch of slightly firmer talalay under 3" or an inch of softer talalay over 3" would act in a similar way and you may not even need the extra inch with a medium Dunlop under. The OMI topper I am talking about is called the Sonoma. Its: "4 inches, 100% pure natural latex rubber sculpted to support and contour to five parts of your body for cushioning support. Covered with 100% certified organic wool quilted between two layers of organic cotton cover." http://www.bedroomsandmore.com/images/products/toppers/organic-latex-wool-mattress-topper.htm Its also $1200 for a king! But all the toppers there that combined latex, wool, cotton, and quilting felt good, and each felt unique and different. I really think the toppers that combined materials felt better than just latex or just wool etc. I don't see how you duplicate this with just pure foam??? I have a feeling that 3" extra firm dunlop under medium dunlop under 3" soft talalay wouldn't be that far off. The 3" Talalay would be a little too thin but the top inch or so of the medium dunlop would add thickness to your comfort layer and then the sag factor of the medium dunlop along with the very firm underneath could give you good support. This is using a "bit" of progressive layering but would still be primarily differential. If you can get the firm Dunlop with the ability to return it then you would have little to lose and I think it may be another "surprise" in terms of how close it could be ... Well, the original config we tried was all dunlop latex, Med over Med over Firm on my side, and Soft over Med over Firm on my wife's side. Both sides were way too firm to me. What you are suggesting is just going back to my wife's original config but with soft talalay rather than soft dunlop on top. I don't think that gets me there. That said, if I can get the firm dunlop with ability to return it would be dumb not to try. Do you know a place (where the layers are the same as Sleepez layers in terms of width)? I think no matter what I do I will want some quilting or a real topper, like the natura wool topper http://www.bedroomsandmore.com/images/products/toppers/natura-classic-comfort-plus-wool-mattress-topper.htm + 1-2" latex (ie http://www.bedroomsandmore.com/images/products/toppers/natura-latex-mattress-topper.htm or something like the englander latex and wool topper http://www.bedroomsandmore.com/images/products/toppers/englander-latex-wool-mattress-topper.htm or the OMI. These are expensive but they just seem better than anything I've been able to cobble together (although maybe if you explain more about how you duplicated the OMI I'll change my mind). In my mind this is what gives that final "pillow-top" feel that I keep going for. |
|
From what I have seen, I don't see anything you have tried that would come close in feel or performance to Xfirm Dunlop under Med Dunlop under Soft Talalay. The layerings you described would be very different and the soft Talalay on top could make a big difference. The underlying support layers would also act much differently than anything you have tried with medium/medium. The irony of all this is that I believe that an original switch to soft Talalay over Medium over Firm Dunlop would have been much closer than anything you have tried since. I believe that the medium in the middle could work really well because it "thickens" your 3" comfort layer and the Xfirm under would likely work even better than a firm under. Zoning of the type in the OMI only makes a very small difference as the zones are very close together (usually @ 4 ILD) so this really isn't a factor compared to real zoning. The convolute is simply creating a higher sag factor which is fairly easy to duplicate (including 3" soft over medium which would have a higher sag factor in the top 4" than 4" soft). The OMI would also be very similar to the soft sleepez in terms of ILD although it may be a bit softer with the convolute. The thick ticking (2 layers of cotton and quilted wool) would also not be that difficult to duplicate with a pad on top if you even needed it. The danger of this quilting would be what happened over time as the wool compressed and a pad that did the same thing would be preferable to me at least. All in all, the OMI is very nice but they "upsell" what it really is in order to justify the cost. I also think that if you even need it that double zoning using what you have would work very well (and better than the OMI zoning). I would phone the two outlets that I mentioned before and tell them what you are doing and see what they have that's not on their website (I'd probably hope that they might give you some kind of deal or maybe comfort exchange given what you have "been through" if you tell your story "well enough") lol. If neither of them have what you want (and make sure it's firm enough) or there is no return privileges, then let me know as I have a few other options that I can post but they may not be quite as inexpensive as the least expensive of these but they would probably be close. I'm also tracking down one or two other places that may have some really inexpensive firm Dunlop but they haven't answered the phone in the past couple of days. Maybe they're on holidays. In any case it seems to me that it's worth a try as it could save you a few bucks. Phoenix PS: the only ones there I would consider as a topper would be the 2" and 3" Natura. The OMI is just throwing money away IMO and the Englander is Dunlop and is unlikely to be soft enough or allow enough sinkin in for what you need. It would just lead to "pattern repeat" (and would also throw a little less away). I can' believe what eiher of them can get away with charging ... one for Talalay and one for Dunlop. There are some really nice 3" and 2" toppers available for way less including the rejuvenite body pillow (which is from LI) and the Pure Latex Bliss toppers (which is a subsidiary of LI). Both of these would be great, have very nice covers, are designed to work together (cover latex). If the ILD is right they would save you lots over the Nautura. This message was modified Dec 28, 2010 by Phoenix
|
|
Is there actually such a thing as extra firm dunlop? I only see firm on those 2 sites you mentioned. If there is should I buy 2 xfirms, 2 firms, or 1 or each? BTW, the FBM 2" over 3" soft over 3" dunlop is killing me - feels way too firm. I think you are right that the FBM is firmer. I'm probably gonna ditch it (along with the wonky convo foam). Thinking about all this dunlop core business, I am going to try the soft over the dunlop med over the talalay medium tonite. I'm hoping the dunlop in the middle will absorb most of the weight and act closer to a standard 6" medium core (which seemed to feel fine in the store). I do think its going to be too soft, especially in the hips. I might add some poster board or something under my hips to try and firm that area. This combination at least seems to feel nice and soft on my shoulders. We'll see tomorrow. They actually had a "firming" pad at the Bedrooms and More store. Maybe I should just buy that and put it under the middle layer? Or what if I put my wool mattress pad in there? It has that stiff backing that seems to firm things. Although I'd be worried it would tear up the foam. And it does seem like maybe I only need firming at the hips? I'll look at those other toppers you mentioned tomorrow too... Thanks again... |
|
There is extra firm Dunlop but neither of them have them listed so I don't know if they have them on hand. These guys have firm, extra firm, and even what they call hard. They often have better deals in their clearance section as well. You only need a 3" layer of X firm under you (unless by two you meant your half and your wifes half). If a medium Dunlop you have is split then you could get away with switching your half of it if your wife is OK with what she has. Not surprised at the FBM ... have been suspecting medium but it may even be more. It's tough to work with "unknown layers" when there are enough unknowns already :). Makes it tough to really know for sure what is causing the effect of a change. With the medium Talalay under, it may compress before the medium Dunlop depending on the relative ILD @25% and what compresses when after that depends on the relative sag factors. This is what I called "order of compression" before. When softer is under firmer, the softer compresses first. This helps parts to sink down but not "sink in". so it could help with alignment but not so much pressure relief. It may even reduce pressure relief slightly as it may change the order of compression so that the talalay compresses before the soft upper part of the medium Dunlop. The Dunlop would start to compress when the compressed Talalay under it became firmer than the top part of the Dunlop. I think a thin firm layer like the mattress pad in the layering can work really well (or even cardboard and other thinner stiffer materials). I am tracking down a place to buy stuff like this but they haven't answered their phone either. I've been hoping someone would try this when I suggested it before as I think it could make a big difference in some cases (depending on what was used) but so far nobody has. If you go this route I'd just put it under the hip area to stop the Talalay from compressing and make the top part of the Dunlop compress. Cardboard or similar may work as well at least for a short while till it crinkled too much to stay firm. I'd sure be interested in how it changed things for you. It could even work better in between the medium/medium Dunlop if it stopped the lower layer from compressing too much and "forced" the upper layer to do the compressing. Phoenix This message was modified Dec 28, 2010 by Phoenix
|
|
1) The guys with the extra firm, thats foamorder.com, i'm pretty sure thats where i got one of the "bad" pieces of foam I currently have. I'm gonna stick to places people trust... 2) I did experiment with putting some poster board under the dunlop piece. Started with like 10 pieces which made things super hard. Was surprised to find that even 1 piece made a noticeable difference. I didn't sleep with it though. 3) What I did sleep with was the soft over dunlop-med over tal-med. And, I think I finally get it! But I clearly need more comfort layers as well. I do notice that when I add the allergy cover and the mattress pad things feel a bit firmer. Do you have suggestions for what I should do? Remove the mattress pad maybe? Add more foam? Wool? Do you think blended vs natural matters for topper? I think I'd probably want something thats like 1.5" latex + wool. You mentioned the Rejuvenite and the Pure Latex Bliss toppers, are those the ones you would add? (I can only find rejuvenite in 3" layers.) Any sites you recommend for ordering? Steve (feeling encouraged!) This message was modified Dec 29, 2010 by st3v3k4hn
|
|
Did I see light bulbs? :) I am guessing that the "bad latex" came from FBM and not foamorder which is a much more reliable supplier. They are very open about what they sell and while their prices may not be the best, I would certainly have confidence that what I ordered from them was what they sent me ... unlike FBM. I am assuming that when you are talking about ordering 2 pieces of firm you mean 2 half pieces ie. one complete layer? I'm hoping that's the case since I don't think you will need 2 firm layers. If you have say 40+ ILD Dunlop under the medium Dunlop, then the medium dunlop would compress first and the top part would feel soft and so "add to" the 3" of comfort you have with the soft Talalay. It would then start to compress and get firmer faster and with this "deeper firmness" in combination with the firm Dunlop under could also give you the support you need. Once you have tried this ... any minor adjustments you may need will be much more clear. I doubt that most people would feel the difference between blended and natural Talalay in a comfort layer but the natural in theory would be a little springier and resilient and perhaps a little bit more "point elastic". I really do doubt though that the difference is enough to make an issue of it. I was mentioning the PLB and Rejuvenite as examples of what I might put over a thicker layer of Dunlop to "duplicate" the OMI. They wouldn't work for you because you already have 3" soft Talalay which should work fine. You may need a thin layer with this but the medium Dunlop could give you what you need if what is under it is firm enough to "make it compress" first. Phoenix This message was modified Dec 29, 2010 by Phoenix
|
|
Yes, light bulb. FInally! I like to think I'm pretty smart but this sure took me long enough... Anyway, I just got off the phone with Shaun at SleepEz. Told him what was going on and he recommended 1 piece of FIRM BLENDED TALALAY. He suggested I could put the firm over the medium dunlop. His reasoning was that either talalay or dunlop should be firm enough (in terms of support), but that the talalay would have a little more give / comfort and so it should help more with the pressure points. Your thoughts? By the way, I think I am going to order a new terry cover because I can feel my sleepez cover is compressing (apparently I am a princess). Thanks (for the millionth time |