| 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? |
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I posted this link in another thread but the chart on page 5 here illustrates some of what I mean http://www.pfa.org/intouch/pdf/ntouch51.pdf If you look at the 7" layer of 1.5 density 43 ILD with nothing on top you will see that it provides more pressure relief for certain parts of the body than much softer layered constructions. This is becasue of it's lower sag factor (allows more sinking in) than some of the softer higher sag factor foams. A lot of thought can go into understanding what is happening with the different constructions illustrated here and understanding "why" there are so many counterintuitive differences in pressure relief. This chart is for back sleeping as well which is "easier" than the greater differences in profile with side sleeping. If someone was using ILD alone to make their mattress with these materials, they would almost certainly have some "issues". Sag factor, and resiliency, and layer thickness plays a major role in mattress construction. Phoenix This message was modified Dec 4, 2010 by Phoenix
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Phoenix wrote: I posted this link in another thread but the chart on page 5 here illustrates some of what I mean http://www.pfa.org/intouch/pdf/ntouch51.pdf If you look at the 7" layer of 1.5 density 43 ILD with nothing on top you will see that it provides more pressure relief for certain parts of the body than much softer layered constructions. This is becasue of it's lower sag factor (allows more sinking in) than some of the softer higher sag factor foams. A lot of thought can go into understanding what is happening with the different constructions illustrated here and understanding "why" there are so many counterintuitive differences in pressure relief. This chart is for back sleeping as well which is "easier" than the greater differences in profile with side sleeping. If someone was using ILD alone to make their mattress with these materials, they would almost certainly have some "issues". Sag factor, and resiliency, and layer thickness plays a major role in mattress construction. Phoenix I sent you a PM with long list of what I have done in terms of layering. |
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LONG list is right (laughing). It'll take me a while to look through it and see if I can see some patterns. Two quick questions ... Could you check your underlying mattress by laying or sitting on it and moving around a bit and pressing on it in different places to see if it seems like it is consistently firm throughout. In your PM your second layout was this: 3/3/09 Firm Dunlop latex, 1" Natura pad. No hip pain, no shoulder pain, legs good, no back pain. It didn't say what happened to cause you to change this. Can you remember why you changed this one? Phoenix |
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Phoenix wrote: Yes ... I would remove the medium talalay and either use the convoluted with the bumps down or the memory foam on top. Either one will give us a good place to start and I would just use the allergy cover with nothing else (except sheets of course). Well I didn't have time to check this yesterday so I slept on the config I described (mf over soft over med over med, no toppers). It felt pretty firm but I fell asleep ok. However I woke at 4 feeling soreness in my shoulders from side sleeping. Got up for a while and when I went back to sleep I think I mostly slept on my back. Have a bit of a backache this morning, which is unusual (in the past thats been a sign of too many soft layers, but I dont think it means that here?). I think Leo's points are valid; I tend to sleep on my back and side, want things really soft for side sleeping but probably need things a bit firmer for back sleeping. I also have another problem - altho I've only had the foam a few years it definitely feels softer to me in the hip area and harder at the middle and edges where no one sleeps. Maybe this is because I am heavy (230-ish) but it seems to be true even on my wife's side. So I hesitate to buy more really soft foam because I don't know how well it will last. Anyway, given that these 4 layers felt too firm, do I really want to try just 3? My wife can sleep on almost anything but she gets pretty tired of me ripping things apart all the time, and I don't know that she would sleep on a loosely filled 7" mattress. Thx again... |
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Anyway, given that these 4 layers felt too firm, do I really want to try just 3? Yes please (smiling). And preferably with the convoluted latex on top. Since you would not be bottoming out onto your base with 4 layers, the "firmness" is coming from an inside layer. It's always best and easiest to find a simple reference point first and work from there. This more simple beginning point will do a lot to help decide where to go from there. I'm "targeting" certain layers to gain information. Before we start, are you sure your wife will be OK with this as we will likely be making a few changes to test effects over the next week or so. I would suggest trying each layering scheme for 2 nights unless it is so uncomfortable that you can't go to sleep on it. Phoenix This message was modified Dec 4, 2010 by Phoenix
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on another thread. This message was modified Dec 15, 2010 by Leo3
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OK ... thanks. "I am sure I started out with 1" then 2", then 3", etc. etc. toppers. When I had less I believe I had back pain." This is also really helpful information as it "points to" a thinner layer being fine for your hips, but we need to make sure it is supportive (has enough resilience) to fill in the small of your back. Phoenix This message was modified Dec 4, 2010 by Phoenix
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Phoenix wrote: Anyway, given that these 4 layers felt too firm, do I really want to try just 3? Yes please (smiling). And preferably with the convoluted latex on top. Since you would not be bottoming out onto your base with 4 layers, the "firmness" is coming from an inside layer. It's always best and easiest to find a simple reference point first and work from there. This more simple beginning point will do a lot to help decide where to go from there. I'm "targeting" certain layers to gain information. Before we start, are you sure your wife will be OK with this as we will likely be making a few changes to test effects over the next week or so. I would suggest trying each layering scheme for 2 nights unless it is so uncomfortable that you can't go to sleep on it. OK, I'll try it. The big problem is what to do with the discarded layers and toppers. Right now they are on the floor in our room; thats the part wifey hates the most... By the way, just read the link on poly foams. Interesting, altho difficult to fully understand. On the chart, I assume lower is better? I've always liked the feel of poly foam (ie my couch) more than latex (ie my bed) but worried that poly foams just weren't durable enough for bedding (esp given my weight). Maybe thats not true, and a poly layer would help? |
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st3v3k4hn wrote: OK, I'll try it. The big problem is what to do with the discarded layers and toppers. Right now they are on the floor in our room; thats the part wifey hates the most... By the way, just read the link on poly foams. Interesting, altho difficult to fully understand. On the chart, I assume lower is better? I've always liked the feel of poly foam (ie my couch) more than latex (ie my bed) but worried that poly foams just weren't durable enough for bedding (esp given my weight). Maybe thats not true, and a poly layer would help? removed. This message was modified Dec 15, 2010 by Leo3
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Using a high quality polyfoam is always an option as a good quality HR foam is slightly less than latex with similar qualities (although in spite of what they say it's certainly not proven that they would last as long). They also I don't believe have the same point elasticity as latex so have some drawbacks there. The chart was very interesting and I spent some time there to make sure I had a logical explanation for the different effects. One of the most interesting things is that ILD is only about the upper 25% of a layer. If you compress a HR foam that is softer in the upper 25% to 65% then it could be much firmer than a lower quality foam which starts off (first 25%) much firmer but doesn't have as much difference when it is compressed and so is softer with deeper compression. This is why compression modulus (sag factor, comfort factor etc) is so important as it is rare that someone actually sinks into a layer exactly 25%. In other words ... the response curve of higher quality HR foam can start off softer but "curve upwards" faster and end up firmer in deeper parts of the layer. If latex was a polyfoam, it would be considered an HR foam. Different formulations of latex will also affect it's qualities although they would all be considered HR. Phoenix This message was modified Dec 4, 2010 by Phoenix
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