Handwarmers S07E05: Hack a Thermacell and use as a propane/butane powered hand warmer
Channel: Mountain Parameters
Date: 2022-12-30

We've all seen the portable propane powered catalytic heaters such as the Little Buddy and Portable Buddy series from Mr Heater, or the Coleman Sportcat. It makes you wonder, why not a pocket sized version of those? Well, I wondered the same thing. Then looking at the Thermacell in front of me, I realized I already had one. Although the Thermacell is marketed as a portable device to repel insects, it uses heat fueled by butane to do that. And another property of butane is, as a hydrocarbon, it will react with a catalyst to create an exothermic reaction, and this is the principle that liquid fuel hand warmers is based on. LNG will work as a fuel source as well as naptha. This, along with an initiative undertaken by some resourceful outdoorsmen who figured out they can hack the Thermacell butane refills themselves in order to refill them and save money, makes the proposition of turning a seasonal device into a year round tool quiver that mitigates two discomforts rather than one, seem lucrative if you are an impecunious senior with no friends on a fixed income such as yours truly.

In a catalytic heater, the catalyst is typically applied to a ceramic substrate in the form of a thin coating or layer. There are several different methods that can be used to apply the catalyst coating to the substrate, including physical vapor deposition (PVD), chemical vapor deposition (CVD), and electroplating.

There are several different materials that can be used as catalysts in propane heaters, including metals such as platinum, palladium, and rhodium, as well as ceramic materials like alumina and zirconia. The choice of catalyst material depends on the specific application and the desired properties of the heater.
In this experiment, we are going to use the same catalyst material that we use to rebuild an old hand warmer: platinum catalyst on a substrate of saffil. And, we are going to substitute a mix of butane and 35% propane that is commonly used as the fuel for winter camping stoves used in mountaineering (as demonstrated in a previous video we made 4 years ago in our 'Off Grid' playlist called 'Refilling butane camping canisters').
The idea behind this is, we are going to use a butane/propane mix of fuel to feed an exothermic reaction with the same catalyst we use in a liquid fuel hand warmer such as a Zippo, Peacock, Jon-e, etc. But, you may ask, "can butane be used to react with platinum to create an exothermic reaction"? Well, I asked ChatGPT to answer this question for me, and here is what it said:

"Yes, it is possible to use butane to react with platinum to produce an exothermic reaction. Platinum is a highly reactive metal that is able to catalyze a wide range of chemical reactions, including those involving hydrocarbons such as butane.
When butane is burned in the presence of platinum, the chemical reaction that occurs can produce heat and light. The heat is produced by the exothermic reaction between the butane and the oxygen in the air, and the platinum serves as a catalyst to facilitate the reaction.
When butane reacts with platinum, the main product of the chemical reaction is carbon dioxide (CO2) and water (H2O). These gases are produced as a result of the exothermic reaction between the butane and the oxygen in the air. The platinum serves as a catalyst to facilitate the reaction and lower the activation energy required for the reaction to occur.
The chemical reaction between butane and oxygen can be represented by the following equation:
C4H10 + 6O2 (goes to) 4CO2 + 5H2O + heat
In this equation, C4H10 represents the butane, O2 represents the oxygen, CO2 represents the carbon dioxide, and H2O represents the water. The heat produced by the reaction is represented by the heat term on the right-hand side of the equation."

Timeline:
00:00 Thermacell disassembly
01:00 anatomy of the Thermacell
02:00 recommended fuel blends
03:00 adding catalyst to the Thermacell burn chamber
03:30 optional hack, using SS mesh to retain the catalyst in burn chamber
04:45 lighting the catalyst: piezo or flame
06:50 heat output test
07:12 cautions
08:45 using a pouch 
09:16 Thermacell caution label
09:50 pyrethroids explained
11:23 SWMBO models pouch on lanyard
11:40 why do this?
13:00 refilling and fuel blends
14:00 conclusions

Links:
Order form for catalyst, carbon felt, and other handwarmer items:
https://forms.gle/yhcMy4Akuq9bdfTo7

Refilling butane fuel canisters tutorial:
https://youtu.be/KGZP-RyMw80?list=PLDXT34Ltvhm_5PNaiwbu_XxhE47eaSAMH