I wish to make a specially shaped ice bag for my back, for which I am undergoing physical therapy, (no slipped disk or arthritis, just have to strengthen the muscle through exercises).
The commercially made ice bags are nowhere near thermally conductive enough, I like cold ice water to numb for 15 minutes followed a few minutes later by a nice hot shower. Helps a lot.
So far I have been double bagging polyethylene garbage bags, wastebacket size and filled with six ice trays plus a quart of cold water tied off with twine. They let the cold of the ice water through very well, but I have to move them twice to cover the area I need. So instead of a 15 minute icing session, it turns into a 45 minute icing session.
So I elected to make my own thermally conductive ice bag in the shape I want. I figure I will cut two identical pieces, then glue them together.
There are thermally conductive plastics, but I really need something in the next couple of days.
The materials I selected to cut the specially shaped bag are:
A) Sheet vinyl, obtained from a vinyl shower curtain sold at the dollar store. Unlike polyethylene, which is hard to glue, many things will stick to vinyl. I would estimate it's thickness at about 6 mils, a little thikcker than the polyethylene garbage bags but probably okay thermally.
B) Thick aluminum foil. Yes, I know it will probably need replacing after several uses, but I am willing to do that.
I tried using PVC pipe glue for a piece of test vinyl sheeting, and the vinyl stuck fine but the glued edges become crinkly. I can live with that, but anybody know of an available glue that won't crinkle the vinyl and make a waterproof seal? I have some PC 11 epoxy, but I am open to suggestions.
And what would make a waterproof seal with aluminum foil?
Any help along these lines would be appreciated.
The commercially made ice bags are nowhere near thermally conductive enough, I like cold ice water to numb for 15 minutes followed a few minutes later by a nice hot shower. Helps a lot.
So far I have been double bagging polyethylene garbage bags, wastebacket size and filled with six ice trays plus a quart of cold water tied off with twine. They let the cold of the ice water through very well, but I have to move them twice to cover the area I need. So instead of a 15 minute icing session, it turns into a 45 minute icing session.
So I elected to make my own thermally conductive ice bag in the shape I want. I figure I will cut two identical pieces, then glue them together.
There are thermally conductive plastics, but I really need something in the next couple of days.
The materials I selected to cut the specially shaped bag are:
A) Sheet vinyl, obtained from a vinyl shower curtain sold at the dollar store. Unlike polyethylene, which is hard to glue, many things will stick to vinyl. I would estimate it's thickness at about 6 mils, a little thikcker than the polyethylene garbage bags but probably okay thermally.
B) Thick aluminum foil. Yes, I know it will probably need replacing after several uses, but I am willing to do that.
I tried using PVC pipe glue for a piece of test vinyl sheeting, and the vinyl stuck fine but the glued edges become crinkly. I can live with that, but anybody know of an available glue that won't crinkle the vinyl and make a waterproof seal? I have some PC 11 epoxy, but I am open to suggestions.
And what would make a waterproof seal with aluminum foil?
Any help along these lines would be appreciated.
You are going to hurt your back more, making the perfect ice pack 😛
The 'old athlete's stand-by is to fold up many pieces of paper towels, wet them, put that into a zip-lock bag, and freeze it. Make two, so one is always ready to go in the freezer, and swap them when the first one warms up. They will conform to your back.
**you could always lay these on a "mold" in the shape of your back, in the freezer.
=FB=
The 'old athlete's stand-by is to fold up many pieces of paper towels, wet them, put that into a zip-lock bag, and freeze it. Make two, so one is always ready to go in the freezer, and swap them when the first one warms up. They will conform to your back.
**you could always lay these on a "mold" in the shape of your back, in the freezer.
=FB=
try a 2 litre "camel Bak" bladder, fill with ice water.
not exactly thermally conductive plastic but a nice sealed, soft, thin, durable waterbag.
Have you tried the good ol' goony bag? (cask wine bladder)
I suggest partially filling it, then placing it across a cross shape in the freezer so you end up with 4 pieces of ice. top up with chilled water.
not exactly thermally conductive plastic but a nice sealed, soft, thin, durable waterbag.
Have you tried the good ol' goony bag? (cask wine bladder)
I suggest partially filling it, then placing it across a cross shape in the freezer so you end up with 4 pieces of ice. top up with chilled water.
A thought came to me that possibly RTV Silicone would bond aluminum foil. The kind used in automotive work for valve cover gaskets and such. Usually black in color and waterproof without question.
whatever you use to stick it on with might be even less thermally conductive than what you are trying to replace.
neutron7 said:
Yes, you are quite correct on that, especially if I go with the aluminum foil for a material instead of the vinyl.
That glued part, however, would not be the part contacting my back. That would be a single sheet of aluminum foil or vinyl sheet, whichever one I go with. The glued part would be on the side.
Incidentally, on second thought the vinyl sheeting is probably not 6 mils thick, that was just an estimate. I shold probably weigh it and divide by it's area to find what it's thickness is, but it is likely closer to 3 mils or so than 6 mils.
True, that would make it less thermally conductive than the cheap polyethylene wastebasket bags, double bagged, that I am using now, but I don't think the reduction will be that significant. It is certainly bound to be much, much closer to what I have I have now than the cloth covered latex water bags they sell in the store, which really cuts down on the thermal conduction.
SY said:
You mean like hot melt glue? I haven't had a lot of success of that in the past even for wood.
Do you mean something else? Please elaborate.
Try a neoprene based contact adhesive.
Around here its called Ados F2. Don't know what it would be in your part of the world.
Watch out for frostbite using Al foil.
Around here its called Ados F2. Don't know what it would be in your part of the world.
Watch out for frostbite using Al foil.
kelticwizard said:
Aggh, sorry I missed this before. Heat activated adhesives are provided in sheet form with all different sorts of compositions, thicknesses, and activation temperatures. Cut the sheet to the shape you want, place it between the two layers you want to bond, and use an iron to seal.
I don't know retail sources offhand (we bought large quantities from Bemis), but I suspect a little web searching will turn one up.
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