I recently started taking flying lessons and found out that many pilots wear ice or cooling vests in order to stay comfortable and sooth airsickness in the warmer months when flying in planes without air conditioning. Additionally, athletes and industrial workers sometimes make use of ice vests. Working outside and feeling overheated? Just throw on your ice vest! These can be purchased, but I found that most were $80 - $100+ and this one cost me less than $15 to make. It is made using a shower curtain as a bladder that holds an ice/gel mixture that is then sewn into a vest that can provide hours and hours of relief from the heat.

Step 1: Materials

You will need:

An old vest with a lining - an old lifejacket would also work great
A shower liner - I used a light weight PEVA liner
Rubbing Alcohol
Diapers - 2 adult diapers for my size, but any kind would work it may just require more
Oven/Parchment paper

Tools:

Soldering iron
c - clamp
scissors
sharpie
copper tubing (optional)

Step 2: Create Your Pattern

Using the vest you have, create a pattern for the bladder. I kept mine about an inch in from the seams of my vest to allow for error and expansion once it was filled. The picture shows how I combined the back (top) and front (bottom) on one side of the curtain. This way I was able to fold the curtain in half (all the markings will still be showing) and get the complete bladder.

Step 3: Weld Your Seams

In order to make the seams in the bladder watertight I decided to weld them using the technique described by instructable user Aleksi (https://www.instructables.com/id/Welding-plastic-ba...).

The two pieces of plastic to be welded together are sandwiched between two pieces of oven paper and then the soldering iron is run over the top piece of oven paper in order to melt the plastic together. CAUTION: Remember to always be aware that burning plastic could potentially release toxic fumes and therefore this should be done in a well ventilated area and with proper precaution.

Be careful not to touch the plastic directly with the soldering iron as it will create a hole!

Be sure to leave an area of seam open in order to be able to fill it with gel later! I left the neckline open.

I chose to create my welds with the sandwich of oven paper and shower liner held against a copper tube in the hope that this would help the lower sheet of plastic heat up and create a more even weld. You will probably also want to practice the technique on some scrap sheets of plastic. I found that lining up my marking on the top of the copper tubing then using the side of the soldering iron to go over it with very small circular motions worked best.

I also created horizontal baffles in the bladder so that when I added the ice/gel it would not all sink down and gather at the bottom after melting.

Step 4: Create the Water/Gel/Alcohol Mixture

Time to harness the superior absorption power of diapers to make a gel that can be frozen to make a leak free ice pack! I got this idea from The King of Random (https://www.instructables.com/id/Diapers-Help-Your-...) but tweaked it a bit by also adding rubbing alcohol to my mixture so that the bladder would be more flexible once frozen and conform to the wearer (alcohol has a higher freezing temperature than water).

The materials we are wanting can be harnessed from the diaper by cutting it open when it is dry and pulling out the cotton and absorptive materials (more messy because the particles fly into the air) or saturating it with water until it can't absorb anymore and then tearing it open. Put what you collect into a bowl and the rest of the diaper can be discarded. Keep adding water and mixing, the cotton can be pulled apart into smaller pieces, until you get the consistency of "gel" you want. Mine was about the consistency of snow and in retrospect I wish I had added more water.

Add about 2 capfuls of rubbing alcohol for every cup of the gel you have and mix well.

Step 5: Fill the Bladder

Scoop the mixture into the bladder through the area that you left open when welding the seams. As you fill it you will have to work it through the baffles in order to evenly distribute it throughout. Use the broad sides of your hand/fingers to do this in order to avoid weakening or punching through the plastic. Make more gel as needed. I filled each area to a depth of about 1/2 inch which took two batches of the gel (two adult diapers).

Step 6: Finishing Up

Now that the bladder is filled, the seam that was left undone needs to be welded shut. I left about a half inch of seam open on the shoulders where there is no gel in order to let any air escape. Since the neckline is curved I welded this area by angling the smaller side of the copper tubing around and underneath it and then holding it in place was able to put the soldering iron to it. DON'T FORGET the oven paper on either side of the plastic. Also be careful with that soldering iron tip as it will instantly make holes that must be patched if it inadvertently hits the plastic directly (happened to me twice).

With the bladder complete all that is left is to insert it into the lining of your vest and sew your lining back. I tore the stitches out of the neckline of my vest which allowed me to slide the back panels and two front panels in with minimal restitching.

Step 7: Enjoy!

After freezing I left the vest out for 5 hours, 1.5 of which it was being worn and it was still cold! So it will provide many hours of relief from the heat. As with any time you are icing, be sure to be conscious of how long you leave ice on at a time and avoid direct contact with bare skin.

Pat yourself on the back for saving $100+. Beat the heat and stay cool!

Additional notes: Some people have expressed concern about mold, and while constant freezing should slow its growth dramatically should any begin to grow, another avenue that could be explored would to be adding chlorine or something similar to the gel mixture.