Sorry if I missed this. How do you do this?
Hey Napper:
I remember a thread where they talked about this here.
It’s sort of like using old physics conversion formulas from high school. I have quite a few laid out depending upon if you’re looking to figure out the approximate density of a piece with known dimensions and weight, or if you’re attempting to determine what the weight of a piece “should” be with know density and dimensions.
If you have a specific scenario, let me know and I’ll be happy to lay out in “longhand” the appropriate conversion calculation, but it might have to wait until I am back in my store on Monday.
Jeff Scheuer
Mattress To Go
Hi Jeff,
Thanks for the response, one choice I am considering has some Chinese involvement in some way. The company is listed on the Certipur website. I was just reading some info on here about being careful with those companies and it also explained if fillers are added to foams along with some other info.
Phoenix shared a link that talked about and mentioned this in the post to show that the base layer spec was inaccurate on a mattress.
Also based on shipping weight (which isn’t always listed correctly) and using it to calculate the weight of the memory foam layers.
I wanted to use this to make sure that the layers were really as advertised if possible or at least add up to the right weight.
Funny , I have been thinking about shipping weights more lately too
Hi Napper,
Well, I can give you an example and you can use the conversion to work back and forth.
If you had a queen 6" polyurethane foam core rated a 2 lb. feet cubed density, to acquire an approximate weight, you could first determine the area of the queen foam block, which would be 60" x 80" x 6", which would equate to 28,800 inches cubed. Divide this by one cubic foot (12" x 12" x 12"), which is 1728 inches cubed. 28,800/1728 = 16.67 feet cubed. If the foam was 2 lb. feet cubed in density, the foam core should weigh approximately 33.33 pounds (16.67 x 2).
Now, I mention this would be approximately, as foam densities are not exact numbers and are variable, but this will give you an idea if you’re in the range of where you’re expecting to be.
You’re also correct that shipping weight isn’t necessarily a reliable indicator of the actual weight of the product, as it can be rounded to a certain level, and in a finished mattress can include the weight of the cover, FR barrier, glues, and even the packaging. You’re better off weighing individual foam layers by themselves.
As for fillers, you may be referring to the polymer density of a foam. So if you had a base foam that was 2 lb in density, and then some gel beads were added to it, it could “weigh” in at a higher density, but the added weight of the gel beads wouldn’t be contributing to the polymer density (the actual foam material). Finding a breakout of the polymer density of a foam that has something like a gel bead additive isn’t something you’ll find expressed generally by foam companies.
I hope that helps.
Jeff Scheuer
Mattress To Go
Hi Napper and Ari,
I’ll “ditto” Jeff’s comments and regarding the polymer density add that regarding density, when it comes to polyfoam and memory foam, the polymer density of the foam (relative to other foams of the same type) is the most significant factor in its durability. This is a matter of foam chemistry. Density is primarily a matter of how much material is in the foam and the composition of that material vs air content. The primary benefit of density is durability. Higher density memory foams in the 5 lb range and higher will be the most durable, medium density memory foams in the 4 lb range will be less durable but may be preferable for some people because of the differences in how some of them feel and perform, and I would avoid any memory foam that is less than 4 lb density unless you are in the lowest budget ranges because of potential durability issues. Ultra high density memory foams in the 6 lb range and higher may be slightly more durable yet but the benefits of greater durability begins to level off above this range (see page 4 here or here for a bit more information about polyfoam density).
Foam additives can be used either as a filler to lower the cost of the foam, increase fire retardancy, make production easier, or they can be added to a foam to change or improve its properties (such as gel materials or some types of filler to improve stiffness) so when there are fillers added to memory foam or polyfoam it’s difficult to know the effect it will have on durability. These fillers can include silica, carbon black, calcium carbonate, various clays and even gel particles, all of which can give the memory foam a higher total density than the polymer density of the foam before the fillers are added.
While additives can increase density and in some cases improve support (especially at the very end of compression), they can also reduce foam durability and make the foam more likely to tear. Being an additive and not part of the cell structure, they can act as abrasives that can break down cell walls. This is why it is important to look at the polymer density when considering foams. Of course chemists are always striving to improve foams and these technologies, but I’m still very comfortable with my recommendations based upon this and the feedback and information I receive on a continual basis from my many industry contacts. So in essence … polymer density remains the single biggest factor in memory foam durability. There are other factors (such as the use of different chemicals and polymers) but these are secondary.
Phoenix