Latex ILDs compared to High Resilience PU foam firmness
| I'm pretty sure my mattress maker told me that the one inch 44 ILD talalay latex layer and the 45 HR high density PU foam 3/4" were very close in firmness. But wouldn't they still have a different sensation? Latex being more bouncy and firm PU being less so.<BR><BR>I think I've just about given up trying to make my latex layers (only 2 inches) work for me. I couldn't figure out why husband's side of the bed felt firmer than mine. I swear mine seems to compress throughout the night and yet when I open my mattress I don't see any sagging or compressions. That includes the coils. But my husband's side didn't seem to be quite that way. Well, I opened his up and found NO latex inside! I had forgotten that I took the two 44 ILD layers and one 45 ID PU foam. He, on the other hand, had three layers of PU foam. 55, 45 and 45. Coils, too. No wonder if was firmer!<BR><BR>So, I kept the 55 PU foam in both of our mattresses and sandwiched the 44 ILD between the 45 PU foam. The 55 is the base over the coils ending up with the highest layer the 45 PU foam. We shall see how it works tonight! If my back is still sore, I plan to order two more layers of HR PU foam in 45 and 55 and we can both forget the latex! I'll keep it around just in case. <BR><BR>I really am beginning to wonder if my back and latex make a good match. I'm doubting it. |
Re: Latex ILDs compared to High Resilience PU foam firmness
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I stopped by a small custom mattress maker after work tonight. They had some foam samples of PU foam and talalay latex and the PU felt a LOT firmer than the same IFD latex. This really has my interest now. Why would this be so? Here is an email exchange I have had with one of the foam companies Them We manufacture custom cuts on high resilience foam and supply it in a ILD 34 which is comparable to the talalay latex ILD 44. We also offer a ILD 45 which is firmer. The reason the numbers seem out of order is because the latex ILD numbers are softer than most other foam products. High resilience ILD numbers are firmer than most other foam products. Me ...what makes you say an HR IFD of 34 is equal to a latex 44? Are the tests performed differently? For example, is latex measured with a 5.6" or 6" sample rather than a 4" sample? I have read in PFA documents that IFD increases with thicknesses, which is why the standard specifies a 4" thick sample. Does it have to do with different "support factors", or resiliency, or what? Them The difference is the density or weight per cubic ft. of a particular foam type. The 3.0 lb ILD #34 HR vs. 5.6 lb ILD #44 latex. The tests are performed identical with different results due to density. Your correct firmness does increase with thickness. Different results due to density? But the Flexible Polyurethane Foam Association says density is not related to IFD: 1.1. Density continues to be one of the most misunderstood properties of polyurethane foams. Some people mentally relate density to the firmness of foams, and that relationship is totally incorrect. Foams with an extremely wide range of hardness can be made at an extremely wide range of densities. DENSITY STANDARDS AND GUIDELINES 25% IFD (indentation load deflection, see chapter 4) is a measure of the hardness of foams; and for example, a 20 pound/50 in2 IFD can be made at densities ranging from 1.0 PCF (pounds per cubic foot) to 10 PCF. The key is that density is in no way related to IFD. |
Re: Latex ILDs compared to High Resilience PU foam firmness
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This will be considered blasphemy by many or even most on this forum, but I am considering using a layer of firm HR foam to add some support to my latex core without spending $900 on another core. It was actually a guy at a custom mattress place who suggested it. The suggestion was for 1" of IFD 44 HR or even 55 foam placed between my two layers of 38. This seems worth a try. HR foam with a density in the vicinity of 3.0 lb should hold up for a good long time. Folks around here love their latex, and for good reason, but let's be honest, firm support isn't latex forte. I do think I would have been fine had I bought the ILD 44 core instead of the 40 (which came in on the soft side), but that's not an option for me now. |
Re: Latex ILDs compared to High Resilience PU foam firmness
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BeddyBye, I saw this post after responding to your Bonnell Coil thread, and now I REALLY think the latex is part of the problem. Latex will compress. It's very squishy even at high ILDs, but when you get off of it it pops right back up. That's why you can't actually see any sagging when you open your mattress. It's not sagging. It's compressing under your weight and pushing back against your body at the same time. The HR foam on your husband's side has completely different properties. It's passive rather than active. It's firm but it doesn't push back. My experience with it is that even at the same ILD it doesn't even seem to compress very much at all when you lie on it. But that might be because it actually is firmer than latex of the same ILD, as Haysdb's input indicated. Personally I find it much more comfortable than latex. I guess you've come to the same conclusion I have about the latex. It's not a good match for your back. I also think that 45 is too firm to qualify as a "comfort" layer over coils. I hesitate to suggest that if you really like the feeling of latex you try no more than an inch and a half of 32 ILD, because you're already having a hard time with latex. After six weeks of torture on a latex mattress I'm kind of wary of the stuff. I like memory foam as a comfort layer because it's completely passive and very good at pressure relief, but that's just me. |
Re: Latex ILDs compared to High Resilience PU foam firmness
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If you can find high density foam, whether it is polyurethane, latex, memory foam, or whatever, it should have a good lifespan. My Grandma has a sofa which has been in use for decades and shows no signs of wear. I would like to dissect it to find out what kind of foam is inside. Just from sitting on it, it feels like high ILD polyurethane. I am guessing it is also high density. I also don't understand why people here are so infatuated with latex. I think the scorn for PU foam was created by the S companies use of low density PU foam that failed quickly for many of the members here. If it is light in weight, expect failure soon. If it feels very heavy for it's size, expect it to last a while. Of course there are exceptions (like Resilitex). |
Re: Latex ILDs compared to High Resilience PU foam firmness
| I would be interested in knowing what is in that couch also. I visited two custom mattress factories yesterday and one commented that quality PU foam showed up on the market 12-13 years ago. He didn't elaborate. I don't know what the state of the art in PU foam was 20+ years ago, but I know that predates high resiliency and high density foams. |
Re: Latex ILDs compared to High Resilience PU foam firmness
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haysdb wrote: This will be considered blasphemy by many or even most on this forum, but I am considering using a layer of firm HR foam to add some support to my latex core without spending $900 on another core. It was actually a guy at a custom mattress place who suggested it. The suggestion was for 1" of IFD 44 HR or even 55 foam placed between my two layers of 38. This seems worth a try. HR foam with a density in the vicinity of 3.0 lb should hold up for a good long time. Folks around here love their latex, and for good reason, but let's be honest, firm support isn't latex forte. I do think I would have been fine had I bought the ILD 44 core instead of the 40 (which came in on the soft side), but that's not an option for me now.
One problem people can suffer from in the search for the perfect component combination is hypersensitivity/princess-and-the-pea syndrome. During my search I suffered this affliction but I've long since gotten past that and now I just sleep without any analysis. Good luck in your search. This message was modified Sep 26, 2007 by kbell
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Re: Latex ILDs compared to High Resilience PU foam firmness
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Something I find interesting is that IFD's of Polyurethane foam take bigger jumps than latex. PU goes from , for example, 33 to 44 to 55 to 77. I have inquiries into several places, including the Polyurethane Foam Association and "the foam guy" from a local custom mattress maker, to see if I can gain some understanding of why PU foam might be "firmer" than latex for a given IFD. One problem with mixing latex and PU foam is that people tend to prefer latex OR polyurethane foam, including memory foam. There just isn't much information out there about mixing the different foams. I occasionally read a comment from someone saying not to mix the different foams, but without any particular explanation for why they think it's not a good idea. Can anyone shed any light on that? |
Re: Latex ILDs compared to High Resilience PU foam firmness
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haysdb wrote: Something I find interesting is that IFD's of Polyurethane foam take bigger jumps than latex. PU goes from , for example, 33 to 44 to 55 to 77.</p><p>I have inquiries into several places, including the Polyurethane Foam Association and "the foam guy" from a local custom mattress maker, to see if I can gain some understanding of why PU foam might be "firmer" than latex for a given IFD. One problem with mixing latex and PU foam is that people tend to prefer latex OR polyurethane foam, including memory foam. There just isn't much information out there about mixing the different foams. I occasionally read a comment from someone saying not to mix the different foams, but without any particular explanation for why they think it's not a good idea. Can anyone shed any light on that? Heck, I have all three in my mattress. PU, latex and some memory foam. Now we'll see how they work together to make my back feel good! I may just have to go to all cotton if I can't come up with a solution soon! |
Re: Latex ILDs compared to High Resilience PU foam firmness
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I submitted the following question to the Polyurethane Foam Association: Are the IFDs of flexible polyurethane and latex measured the same way? A foam supplier has told me that an HR foam with an IFD of 34 will be about equivalent in firmness to an IFD 44 talalay latex. He says it relates to density, but pfa.org documents are explicit that IFD is not related to density. http://www.pfa.org/jifsg/jifsgs1.html It can't be related to resilience or support factor because latex will typically be at least as good as a PU foam in these two areas. Their reply... [1] IFD is measured the same way for both products. Many latex foam rubber products have greater compression modulus than conventional foam and HR foam products. In common terms, that's Support Factor. Here's what it means: IFD at 25% is a measured resistance to compression force. You could specify an HR foam with a 45 lbs IFD at 25% compression and essentially it would be equal to a latex product with an IFD of 44 lbs at 25% deflection IN TERMS OF SURFACE FIRMNESS. If you were then to measure the IFD at 65% compression, theoretically, the latex sample would have a higher number (greater support). Bob Luedeka Executive Director In other words, the ILD 44 latex should be MORE supportive than the 44 HR since it will have the same 25% ILD, and therefore the same surface firmness, but a higher 65% ILD, and therefore a better compression modulus or "support factor," for superior deep down support. I have also asked this question of Dewey at FloBeds. He didn't know the answer but was going to talk to his foam guy whom he says has a good feel for the equivalencies of the two foams. I am going to "get to the bottom of this" if it's humanly possible. [1] The forum rules specify that we can't quote emails, but this is purely informational and not personal in nature. This would seem to be in keeping with the "spirit" of the rules, if not the letter. This message was modified Sep 28, 2007 by haysdb
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Re: Latex ILDs compared to High Resilience PU foam firmness
I received samples of three different ILDs of 3.0 lb HR foam today from FoamOnline.
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