A 3" queen layer would be 8.333 cu ft so if a layer weighed 31 lbs this would be 3.72 lbs/ft3 or 59.59 kg/m3. If a 3" layer weighed 43 lbs it would be 5.16 lbs/ft3 or 82.66 kg/m3. While these numbers are a little different from yours … they are close enough and it’s clear to me that within any margin of error in the thickness of the latex or the weight that they are not the same density. I have no explanation why you would have been shipped two layers that were marked what they were and are that different as it is certainly not within the normal variance of Dunlop latex. You can see Latex Systems density/softness ratings here.
I would be curious about any other differences between them in terms of the pincore patterns and in your perception of the relative softness of each layer. If you have something heavy and dense like a bowling ball then you could also put it on each layer and see how far each one sank in to have an approximate comparison of their relative firmness. A picture would be great if that was possible as well. I would also be curious to see what Sleepwarehouse said if you talked to them.
I certainly understand your frustration and I wish that the ratings that you see all over the internet for Dunlop were more comparable, consistent and accurate. I know that some companies such as Latexco actually test the layers they stock that are manufactured by other companies (such as Latex Green) for ILD and assign their own test ratings to them so at least there is some consistency there.
It’s certainly easier to test a mattress in person and let your body tell you how well it works than going by ILD numbers that you aren’t certain are accurate but of course this isn’t possible when you are ordering online or trying to “approximate” another mattress.
I should have explained a little further. The reason for our small discrepancy is because I used two different scales to weigh each piece of latex. The scales were slightly off, but close enough for me to be confident of the accuracy within reason. I only used one of the numbers while doing my calculations, but posted the range of the weight in my thread. In addition, I did several conversions between standard and metric and was rounding off the numbers. I probably should have not included any numbers except the final density, or all of the exact numbers instead of a range.
I had seen those numbers on the Latex Systems site, but they do not completely jive with the labels on their products. One of my labels states 70-75, and their site lists the softest as 75-80. My other label states 90-95, and the site lists their firmest as 85-90. I attached pictures of my labels for reference.
The pincore patterns are identical and unremarkable. I can definitely feel that the piece I calculated to be 85D (and labeled as 90-95D) is firmer than the one I calculated at 60D (and was labeled as 70-75D). I can include a picture of them being compressed by a 53 lb kettlebell if there is a reason for seeing the relative difference, but simply compressing the latex between two flat palms reveals which one is firmer.
I emailed them before posting my thread (my thread was basically a copy/paste of the email), but I have not heard back yet. I also emailed Latex Systems directly, but I do not know what my chances are of hearing back from them. Although, Radium did reply to me when I emailed them directly to confirm the Talalux ILDs.
The most frustrating thing is that the latex I received was demonstrably SOFTER than what I ordered (received Talalux ILD 19 instead of ILD 22 for the top layer, a dunlop 60D instead of 75D for the middle, and a dunlop 85D instead of 95D for the bottom layer), but when I put the mattress together, it felt FIRMER than what my wife and I both expected based on our testing. What are the chances that the ILD 19 was just too soft and was being compressed too much, allowing us to feel the firmer dunlop underneath?
Honestly, I’m not convinced it would be any easier by ordering locally. With this sort of inconsistent labeling, how can anyone building a mattress replicate their floor models? Unless I was buying the exact floor model that I tested, it seems the chances are good that what I would receive would be different than what I tested.
In the “firm” layer … the bottom part seems very odd to me and not typical of a latex layer that has a more consistent look from top to bottom (even though the top of a Dunlop layer would be softer than the bottom to some degree because of the latex particles settling during manufacturing).
Am I assuming correctly that this isn’t part of the layer itself but something that the layer is sitting on top of?
Other than that I have no good explanations for the differences and I’d be interested in what both sleepwarehouse and latex Systems say.
I would say that the odds are higher that the deeper layers are the main contributors because there is not a lot of difference between 19 ILD and 22 ILD and in a “blind test” with a 3" layer on top of similar middle and deeper layers most people would not feel a great deal of difference (and some wouldn’t feel it at all). Even though the layers you have appear to be different from what you expected (softer in specs and firmer in fee) … you also don’t know for certain how they may compare to the mattresses you tested which could also have specs that are different from what you thought they were.
What I meant is that if you buy locally then you don’t need ILD numbers at all and there is no matching to do because your body will tell you what you need to know about the balance between pressure relief and support on a mattress regardless of the ILD of the layers. The mattresses they have in stock of the same design would be using the same materials and components as the floor model regardless of how they were listed. Replicating a mattress based on specs on the other hand is always an approximation at best and depends on your ability to determine both the correct specs of a test mattress and then duplicate them with your own materials which isn’t always easy or possible whether you are buying the “replacement” materials locally or online. It’s one of the reasons I usually suggest this is a much more “risky” approach. Another reason as well is because sometimes even seemingly minor differences in design, materials, or components can also have an unexpected outcome if someone doesn’t have enough experience to know the effect they may have.
This can be very frustrating but it is also the reality of the industry as a whole
[quote=“Phoenix” post=19022]In the “firm” layer … the bottom part seems very odd to me and not typical of a latex layer that has a more consistent look from top to bottom (even though the top of a Dunlop layer would be softer than the bottom to some degree because of the latex particles settling during manufacturing).
Am I assuming correctly that this isn’t part of the layer itself but something that the layer is sitting on top of?[/quote]
You are correct, what you see at the bottom of the photograph is carpet. Right now, the two layers are lying on bedroom floor while await the talalay replacement.
I’ll let you know what I hear back from Sleepwarehouse. At this point, I’m hoping they are willing to just let me hold on to these “incorrect” dunlop layers until I can try them with the new topper. I’d like to be able to do that and still preserve my rights to have the order corrected though, especially since I am skeptical that a 60D middle layer will provide enough support and I think putting the 85D over the 60D would be pointless. Wouldn’t it?
The other thing I forgot to mention is the foundation. I know that the mattress I tested was on a slatted foundation. I am using the foundation that went with the Simmons Beautyrest Exceptionale. It appears to be heavy gauge wire covered in heavy cloth. It seems very stiff and does not have any springiness that I can detect. Although most local and online mattress retailers told me this foundation would suffice (The Natural Mattress Store is the only one that didn’t), I am concerned about the spacing of the wires. I don’t even know if “wires” is the correct term. I can’t see them through the cloth, but they feel large enough to be called small rods. Semantics I suppose…
That’s good news. I kept looking at it and couldn’t figure out what it was
It wouldn’t necessarily be pointless because having the firmer layer in the middle would reduce the amount your heavier pelvic girdle sinks down into the mattress which can improve alignment and support vs the other way around. It could also slightly reduce the depth of the pressure relieving cradle and create a slightly firmer sleeping surface as well.
The foundation is probably a Triton foundation and you can see a picture here. It would be a little more giving than solid non flexing slats but I would also be a little bit hesitant to use these types of wire grid foundations in the longer term with an all latex mattress (that has latex on the bottom layer of the mattress) for the reasons in post #10 here. Softer latex would have more risk of sinking into the wire grid than firmer latex.
Phoenix, do you know if the density of a layer of latex is determined while taking the pinholes into account? Sleepwarehouse is implying (but not flat out stating) that the density rating does not take the pinholes into consideration, and that is why my layers of latex weigh less than I expected by simply using the formula d=m/v.
Do you have any resources for how much a 3" queen layer in 75D should weigh?
As far as I’m aware it is the density of the layer as it is rather than the “implied density” if the pincores were filled in. It would be difficult to calculate the density with the pincores filled in because the pincores are part of the manufacturing although the size, spacing, and pattern of the pincores certainly affects the softness of the latex (along with the compounding formula used as well as the air/latex ratio when the latex is foamed). The pincores are not “punched out” after manufacturing in other words in latex that is produced in a mold. I do know for certain for example that Latexco’s Puralux has separate density figures for their continuous pour Dunlop latex for the versions with and without pincores (that are punched into the latex afterwards if desired) and the ones without pincores (using the pincore sizes and pattern they punch into the latex) are about 11% higher density in all versions.
There is also a possibility that different manufacturers may calculate their density differently. I’ll ask a few people to see if there is a consistent response.
A queen 3" layer would be 60" x 80" x 3" = 14,400 cu in / 1728 = 8.333 cu ft.
Thanks Phoenix, “implied density” is a good way to put it. That is what I need to figure out, is the density rating a true density of the layer “as is” (with the pinholes), or the density of the latex without the pinholes.
I should have specified that what I meant was, did you have any resources like a specification sheet on a particular pieces of latex? I was going to use the weight and density rating that the manufacturer provided to do the calculations and determine if it was an “implied” or true density.
Post #2 here from an earlier reply to you should be helpful as a reference although there would be some variation in the density and ILD between manufacturers because of differences in the compounding, manufacturing, and raw materials.
These Dunlop specs originate from Latexco which tests the latex layers “as they are” and the specs for the Talalay are for Latex International.
No, right now I am not concerned with the relationship between density and ILD. What I am looking for is something from a manufacturer that provides the weight and density rating of a piece of latex with a stated size and thickness. As in, “Here is a 3” queen-sized (or any other stated size and thickness) piece of latex in XX density, and it weighs XX lbs."
If I had that information, I could then calculate the volume of that particular piece of latex, and divide the weight (provided by the manufacturer) by the volume I calculated. If the answer equals the density rating provided by the manufacturer, then I would know that the density was calculated with the pinholes. If the answer was lower than the density rating provided by the manufacturer, then that would tell me that maybe the manufacturer calculates density without the pinholes.
Unfortunately I don’t know of any sources for both of the “specs” you are looking for (density and the specific weight of a layer). Most manufacturers I’m aware of only provide density and ILD information not the weight of individual cores or layers.
You mentioned earlier that you were going to ask around about whether or not the density of dunlop is calculated with or without the pinholes, and see if you received consistent responses. Any luck on this?
