Polyurethane Upholstery Foam As A Large Sponge?
There are a lot of people on this forum with knowledge of various materials, as well as people with experience upholstering car seats, so I thought this forum would be a good place to come for advice.
I have the need for a very large sponge, about 4 feet by 3 feet. The thought occurred to me to try upholstery foam. There is a store that sells all sorts of foams in the area in large rolls, but I wonder if I should make sure I get open cell foam or will closed cell do?
The sponge will be frozen and then thawed repeatedly, will that disqualify polyurethane as a material? It will be coming into extensive contact with my skin, would that be a problem?
Apparently there is open cell and closed cell polyurethane foam manufactured, as this webpage testifies.
Any advice on the use of polyurethane foam as a sponge, or advice on how to get a large piece of sponge material if polyurethane is not appropriate, would be appreciated.
You would definitely want to use open cell foam for that application. If you use closed cell foam it will not want to absorb much at all. Think about it, the cell walls are closed. As far as freezing and that it depends on the actual formula that is used. The range of polyurethane material is as wide as you can imagine. As far as skin contact I am not sure exactly what you are insinuating there! But polyurethanes are commonly used in medical applications as they are typically fairly inert once molded. 4' X 3' shouldn't be a problem but that is where you lost me and contact with your skin. Do I know of which I speak, yes I have been a polyurethane molder for many years. All types of thermoset urethane's and then some.
You don't say whether you are interested in water absorption or not. I would think freezing a water saturated sponge would cause breakdown, but that is simple to experiment with.
Sunlight is usually a no-no with upholstery foam - turns it yellow and breaks it apart.
Is this a camping roll? Generally those are closed cell, but they make open cell ones with an attached bladder and valve that are called "self inflating".
Thank you very much for both of your swift answers.
The reason I am interested in this is that my entire back needs icing. A big absorbent sponge might prove useful, hence the questions about freezing and skin contact. :)
Have you heard of reusable plastic ice cubes ? Might work well
placed is a cloth bag with insulation on the back and sides.
Or those freezable sheets of plastic gel pockets.
Just did a quick search and found a couple recipes for DIY cold packs using freezer bags:
one uses straight dish soap
one uses a mixture of water and rubbing alcohol (3:1 and 1:1 are mentioned)
Thank you for your suggestions.
I've seen the reusable plastic ice cubes but my problem is that the plastic around the ice is fairly thick, and since plastic does not conduct heat well it will probably take a long, long time for those cubes to chill something.
I was warned off the gels, (generally blue), because of a training book I read long ago which said they don't send the cold deep into the muscle. This opinion was seconded by a research chemist who told me that when ice changes state-from solid to liquid or liquid to gas-it absorbs all the heat in the surrounding area to make the change. Gels do not change state, hence they are just cold items on top of the muscle that don't send the cold deep.
Previously I tried using salt water in a water bag so the water wouldn't freeze in the freezer, thereby saving me the effort of loading ice cubes into it. Didn't work-it was much colder with salt water than with ice cubes in fresh water, but the cold did not go down into the muscle at all. This was before the chemist told me about the change-of-state thing, which explained it all.
There are freezable sheets of pure ice pockets, but once again the pockets are thick plastic and there doesn't seem to be much ice in those pockets. It looks like it would take a long time to cool anything.
10 trays of ice in a double-bagged contractor's trash bag is what I am using, and while the plastic in the bag slows down the cooling, the plastic walls are relatively thin, (two .002 in layers), that there is enough ice in the water to largely overcome that.
The method is effective, my back is improving, but oh my gosh is it ever unwieldy and time consuming. Not to mention that I live in fear of springing a leak all over the couch! :)
Thanks again for your suggestions. As I explained before the gels really don't thrust deep into the muscle, only ice does that.
Not sure what a chilled waterbed is, but it sounds expensive. I would need actual ice in the water, just cool water doesn't seem to work as well.
The frozen packs with the dish soap and alcohol solution are good, but as long as they are liquid I might as well just fill them with water. I'm worried about leakage out the freezer packs as they get used repeatedly, as well.
Here's one thing I was thinking of-tube ice. Just put a whole mess of these onto a towel, (backed by a plastic sheet), on the bed and lay down, let them melt inside the tubes and impart the cold into my back. I don't think the fact that there is some sugar in the water inside the tubes will change the cooling action too much. When I'm done and taken a hot shower afterward, I'll just put them into a box and stick 'em in the freezer.
Only trouble is, so far no supermarkets are carrying them at this time of year. But I plan to keep looking.
Again, your suggestions are most appreciated.
I went to the store that I thought carried foam, and found that I was in the wrong store. Only trouble is, now I can't remember which could be the right store. Which brings up an unrelated question, which is in worse shape, the back or the brain? :)
Since you work with polyurethane foam, I wonder if you could answer a question or two.
1. Do you know any kind of store which might carry open cell foam? There is an upholstery store nearby, but if they don't have it I was wondering if open cell foam might be used in some industrial process where the place might let you have a small piece for a small fee?
2. I have seen some mention of open cell polyurethane foam in spray form, and I wonder if that can be used safely once it dries. They say don't let it get wet, but that is only because it's value as insulation declines if it gets wet, not necessarily because of danger.
Any advice you might have would be greatly appreciated.
I'm not disputing things here, I'd just like a better explanation and understanding.
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