Arm Coolers?

Maybe a squeeze bottle with mister?

…. I mean like the arm warmers but designed to offer Broad spectrum uv protection and a cooling effect

You mean something like a wet shirt sleeve(;

Check out Desoto skin cooler line. I use a long sleeve jersey and cap for cycling. Even the black is supposed to reflect sun nad provide cooling. Get it wet and it feels great. Read the FAQ regarding UV blocking. Blocks UV B but not A. They still recommend wearing sunscreen.

http://www.desotosport.com/category/skincooler

*edit…just realized you were talking MYOG. Regardless….the Desoto stuff works pretty well. If you're only interested in the armcoolers, they have those.

I'm experimenting with a couple different ones after burning my arms. From what I can gather, it's all in the material. If you can find the right kind of material, they are easy to make, it's just a tube after all. I doubt you will be able to find the right kind of material, at least not easily. Check out Pearl Izumi, Columbia has some, and Novara are 3 companies I've looked at. The Pearl Izumi ones are weird, the black and the white fabrics are completely different.

The skincooler pannels appear to be very breathable fabric. However when you make a fabric very breathable yhou increa the spacing between fibers and that can allow light to get through. The skincooler fabric is located on the underarms and sides of the body because those locations get less sun exposure. That is also why that also recommend sunscreen.

The rest of the shirt appears to be a slightly denser wiking fabric. Any good dense fabric that you cannot see through will block UV. For hundreds of years people have been whereing long sleave cotten shirts to prevent skin burn. prior to invention of sunscreans skin cancer rates were muchlower than they are today. I have been wearing long sleeve shrits for sun protection for about 20 years when hiking and have never gotten sunburned under the shirt.

In short the only way fabric can cooler is by allowing it to breath more, reflect more light, and by wiking moisure away from your skin. The Desoto shirst do that very well but as a consiquence they don't provide your with as much sun protection as your would get from a dense nylon or cotten shirt. A wet shirt will provide way more cooling fthan any dry fabric.

As a road cyclist and a hiker, my opinion is that arm coolers work quite well when on the bike but, they are almost useless while hiking to cool your body. When on the bike, you are riding 15-20 mph and faster and with the air flowing over the wet fabric, you get the cooling effect. Also, taking an extra bottle of water with you to rehydrate the arm coolers is no big deal, as you can almost always refil your bottles when needed and the weight penalty on a bike is a non issue.
While hiking you just don't get the same effect as you do with the higher traveling speeds on a bike and to carry enough water to keep the sleeves wet every 10-15 minutes is counter productive because of weight.
I know this is far from MYOG but, I bought myself a couple of very light weight, white, long sleeve, UPF 30 material shirts from Rail Riders for desert/summer hiking that work very well.

Terry

If you ever decide to purchase I would check out the mountain hardwear product "Way2Cool Arms." Its made of a new fabric for them called Cool Q Zero, really neat stuff. The fabric supposedly "provides an immediate and ongoing cooling sensation." I can attest to a cooling sensation, at least in the short term, as the demo was pretty quick.
http://www.mountainhardwear.com/Way2Cool%E2%84%A2-Arms/OM5505,default,pd.html