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.
http://www.foamforyou.com/Foam_Specs.htm
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.
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.
http://www.foamforyou.com/Foam_Specs.htm
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.
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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".
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".
I'm thinking either a bunch of these (Thera Med ICE GEL CryoPack, Large - Walmart.com) or a chilled water-bed would be a good solution for that.
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)
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Sreten:
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!
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!
Ron:
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.
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.
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Kindhornman:
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 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 a physicist or chemist, but this doesn't sound right to me. That all the "blue" gels I've seen change state from gel->solid->gel as they freeze and thaw is one thing. But more importantly, for virtually any material undergoing a thaw, if it doesn't "absorb
I'm not disputing things here, I'd just like a better explanation and understanding.
Sofa:
Perhaps the gels have improved since the book was written, (1970's), and maybe they do freeze now. The advertising for them say they remain flexible, which would tend to indicate they are remaining in a semi-liquid state, but perhaps I got it wrong. In which case, I will try the gels-they are certainly cheap enough.
I think the point with the very cold but unfrozen salt water in the water bottle and the blue gel which I told the chemist remained unfrozen, they do not take in surrounding heat from the environment because they are not undergoing a change of state.
If the gels do in fact freeze in the freezer and then unfreeze as they are applied to the body, that would change that.
Perhaps the gels have improved since the book was written, (1970's), and maybe they do freeze now. The advertising for them say they remain flexible, which would tend to indicate they are remaining in a semi-liquid state, but perhaps I got it wrong. In which case, I will try the gels-they are certainly cheap enough.
I think the point with the very cold but unfrozen salt water in the water bottle and the blue gel which I told the chemist remained unfrozen, they do not take in surrounding heat from the environment because they are not undergoing a change of state.
If the gels do in fact freeze in the freezer and then unfreeze as they are applied to the body, that would change that.
Let's see.
I don't want to get into the physics here so I will just say I don't think so on the state of change references and the difference between the gel and water.
I'll stay out of whether this sounds safe for your health.
If you took a piece of foam as large as you are talking about and got it wet it would be very heavy, it will hold a lot of water. As far as getting an open cell foam in a spray can I highly doubt that it is either flexible foam or open cell. It is most likely closed cell low density foam for insulation or something like that. Unless this was some sort of sculpted foam shape I don/t see that you would get anything less than a flat hard block of ice with a foam filler. You would still need to put it inside of something to hold the foam and water, otherwise it will form to the freezer and stick to the walls and never come out.
I don't want to get into the physics here so I will just say I don't think so on the state of change references and the difference between the gel and water.
I'll stay out of whether this sounds safe for your health.
If you took a piece of foam as large as you are talking about and got it wet it would be very heavy, it will hold a lot of water. As far as getting an open cell foam in a spray can I highly doubt that it is either flexible foam or open cell. It is most likely closed cell low density foam for insulation or something like that. Unless this was some sort of sculpted foam shape I don/t see that you would get anything less than a flat hard block of ice with a foam filler. You would still need to put it inside of something to hold the foam and water, otherwise it will form to the freezer and stick to the walls and never come out.
I have gotten ~1ft^2 freezable gel packs from vegetable transport boxes. For free. Also from medical transport boxes. May be worth a try at those prices. The freezepop idea seems like good outside the box thinking (or more literally, inside the box) but they may not be large enough to be useful, so quite a few would be needed. Anyhow, I'm thinking of the closed-cell foam used as an insulator, with a multi-pocketed "pillowcase" that holds the frozen contents in place, decreases heat absorption from the wrong side, and the entirety is form-fitting and reusable.
I use the gel packs designed specifically for medical use and they work fine. The gel can be put in a freezer or heated up in a microwave; they work just as well as heat or cool pads. They come with a liner to go on the outside to reduce the risk of frostbite or local burns. The gel kind of looks like pea-shaped blobs.
If I were you I would check them out, maybe start with a search on Amazon where you can also check out some reasonably reliable reviews.
Your foam idea is not out of the question but I don't think it would be as effective. Note (already mentioned) that most manufactured foams are UV-sensitive and break down with exposure to light. A typical example: auto upholstery; they are always covered with a UV-blocking material such as cloth, vinyl or leather, and often a UV-blocking plastic between them for good measure.
Closed cell foam would be used for things like floating docks or insulating foam (don't absorb water; hold air in the cells), you want the open cell stuff if you need sponge ability.
I can't offer much advice on what exact foam to get; the truth is polyurethane is so versatile a material that the properties are nearly unlimited (so the choices being currently manufactured are mind-boggling); softer than (natural) sponge thru harder than any (natural) rubber.
If I were you I would check them out, maybe start with a search on Amazon where you can also check out some reasonably reliable reviews.
Your foam idea is not out of the question but I don't think it would be as effective. Note (already mentioned) that most manufactured foams are UV-sensitive and break down with exposure to light. A typical example: auto upholstery; they are always covered with a UV-blocking material such as cloth, vinyl or leather, and often a UV-blocking plastic between them for good measure.
Closed cell foam would be used for things like floating docks or insulating foam (don't absorb water; hold air in the cells), you want the open cell stuff if you need sponge ability.
I can't offer much advice on what exact foam to get; the truth is polyurethane is so versatile a material that the properties are nearly unlimited (so the choices being currently manufactured are mind-boggling); softer than (natural) sponge thru harder than any (natural) rubber.
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I have some therapeutic gels - they do get hard, then soft after a while - they last a fair amount of time. I know that most gel ice packs are not meant to be in contact with skin without a (dry) cloth barrier. You can get frostbite.
The change of state issue is the latent heat of freezing, which allows the pack to stay at essentially the same temperature as long as there is a mixture of ice and water. The same thing happens as a liquid boils - the liquid stays the same temperature until it boils dry.
When I had a knee injury, I got this really neat bag that surrounded my knee and was connected by a tube to a thermos of ice water. You would raise the ice water above the knee and the bag would fill with cold, then when it got warm, you lower the thermos, water drains out and mixes with ice, gets cold again, and you raise it above the knee again.
I'm thinking you could get a long length of tubing, zig-zag it across your mattress - lay on it and pump cold water from a 5 gallon bucket full of ice water through the tubing with a pond pump
I might have rejected this idea too quickly. Previous to this morning the reusable ice cubes I saw online seemed to be thick plastic with a little bit of water inside which I didn't think would get things very cold, and freezable sheets of gel or water seemed encased in thick, thick plastic-great for durability, not so great for thermal conductivity.
However, I saw these sheets here just now:
Amazon.com: Flexi Freeze Refreezable Ice Sheets 3 pack: Sports & Outdoors
They are large and full of genuine ice. It might take 4 or 5 sets of three to do a whole back at once, but at $14 the total price would still be well under $100 which is reasonable.
Got a couple of other things going right now, but these are fascinating and might well be the way to go.
Sorry, came to this late.
Yes, open cell foam.
Probably OK for contact unless you have an unusual sensitivity to small concentrations of formaldehyde.
The stuff about depth of cold penetration is nonsense. Thermal flow depends on temperature gradients- as long as you keep changing out the gel packs to maintain the low temp, the skin/fat/muscle doesn't know what the thermal absorption medium is.
Yes, open cell foam.
Probably OK for contact unless you have an unusual sensitivity to small concentrations of formaldehyde.
The stuff about depth of cold penetration is nonsense. Thermal flow depends on temperature gradients- as long as you keep changing out the gel packs to maintain the low temp, the skin/fat/muscle doesn't know what the thermal absorption medium is.
When I had a knee injury, I got this really neat bag that surrounded my knee and was connected by a tube to a thermos of ice water. You would raise the ice water above the knee and the bag would fill with cold, then when it got warm, you lower the thermos, water drains out and mixes with ice, gets cold again, and you raise it above the knee again.
I'm thinking you could get a long length of tubing, zig-zag it across your mattress - lay on it and pump cold water from a 5 gallon bucket full of ice water through the tubing with a pond pump
Sounds like a good idea.
For some time I have had my eye on this-I'm pretty sure I'll get one eventually. Only thing is, it would require 4 bags to cover my back, and I have to check with the seller to see if the unit can power four big back bags at once-I don't want to have to shift position 3 times.
Aqua Relief System (Pad Included) | Hot and Cold Therapy Machine
Much thanks, SY.
Some time ago I got two tips on cooling. One is to take an 8 ounce styrofoam cup, fill with water, freeze overnight then peel the styrofoam halfway down and apply the frozen water to the area. If you can reach the area with your hand, it's the best.
However, this is my back.
The other advice was to use a bag of frozen peas or other vegetables. I tried that, it was okay. I'm going to try it tonight. I'mputting a chedap plastic dropcloth on the bed, then a towel, then a whole mess of frozen veggie bags, followed by a wet towel on top, (something I didn't use before), then lay down on top for 15-20 minutes.
I figured I can't lose. If it works, I found an easy way to cool my back. If it doesn't, after 14 one pound bags of chopped broccoli, I won't have to worry about colon cancer for quite awhile!
Some time ago I got two tips on cooling. One is to take an 8 ounce styrofoam cup, fill with water, freeze overnight then peel the styrofoam halfway down and apply the frozen water to the area. If you can reach the area with your hand, it's the best.
However, this is my back.
The other advice was to use a bag of frozen peas or other vegetables. I tried that, it was okay. I'm going to try it tonight. I'mputting a chedap plastic dropcloth on the bed, then a towel, then a whole mess of frozen veggie bags, followed by a wet towel on top, (something I didn't use before), then lay down on top for 15-20 minutes.
I figured I can't lose. If it works, I found an easy way to cool my back. If it doesn't, after 14 one pound bags of chopped broccoli, I won't have to worry about colon cancer for quite awhile!
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Definitely a unique and useful idea for the long run. If I find a convenient way to ice, I plan to do it once a week even after the back heals, (which it is doing rapidly, by the way).
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