Coolfab is a custom metal-fabrication shop in Zeeland, Michigan. They are putting out some of the most innovative rocket stove designs that I have seen anywhere, at quite reasonable prices.
I recently had a chance to test one of Coolfab’s Flaretop stoves. It is a real beast of a rocket stove, with its cooking surface standing 27.5 inches above the ground and weighing in at 52 pounds. The flaring at the top of the stove allows for a respectable 12 by 12-inch cooking surface. This larger surface area enabled me to simultaneously roast hot dogs and boil a half gallon of water. I found that using the stove was a lot of fun. My wife, “Kari” went so far as to express interest in similar cookouts every week.
At the time of this writing, the Flaretop cost $200 plus shipping at the Coolfab company’s Facebook page. (At the time of this writing, only Facebook users had online access to Coolfab products.) A basic model, which is much more portable than the Flaretop, costs $100 plus shipping — estimated at about $40. If you have a custom design of your own in mind, Caleb, the owner of Coolfab, could probably build it for you. I highly recommend his work.
Background
The great advantage of rocket stoves is that they can be used to cook while using only small sticks and similar biomass as fuel and while producing minimal smoke. If you have access to this type of biomass, a rocket stove might provide a quite viable short-term cooking solution for a grid-down situation.
I have an almost unlimited supply of small sticks and similar biomass in the woods surrounding my home. I have so much, in fact, that it is an ongoing battle to get rid of it all. Kari and I could cook all of our meals for a year on a rocket stove without even keeping up with new growth. So we always keep a rocket stove around, just in case.
Recently, I ran across Coolfab online. I was impressed by both the variety of the stoves that they offered and by their reasonable prices. I contacted Coolfab and asked if they could loan me one of their stoves for testing and evaluation. Caleb was kind enough to agree. He suggested the Flaretop as an especially interesting model. I thought that was an excellent suggestion. Not long afterward, the loaner stove was entrusted to my care.
First Impressions
The stove is constructed of three shafts of 6 x 6 inch square 11-gauge steel tubing.
The vertical shaft (chimney) runs about 16.5 inches from the base of the stove to the bottom of the flaring. The flaring then continues upward for another 9.5 inches. It is topped by a 12 x 12-inch grate that is custom-cut from a sheet of mild steel. The grate is hinged and has a handle on it for easy opening. The horizontal (air-intake) shaft runs 13 inches from the back of the chimney to the opening for the removable ash pan. Coolfab suggests leaving the ash pan open about two inches to allow for a good draft during the operation of the stove.
The diagonal (fuel-feed) shaft runs 14 inches from the chimney to the hinged door. The door has a spring handle to keep it cool even when the stove is hot.
The outside of the stove that I tested was seasoned with cooking oil just like cast iron cookware is seasoned. Caleb indicated that he had tried some other finishes, but that they tended to eventually flake off. He decided that seasoning was more food-friendly than the other alternatives that he had tried.
Stability is provided by four feet that project in pairs about four inches from two sides of the stove.
The quality of the welding on the stove is outstanding.
There is a handle on the back of the chimney, but the stove is so heavy that it would be an awkward carry for just one hand. The stove could conceivably be used from a vehicle or cart, but is really too heavy and awkward for use with a pack animal.
Fuel Collection
I used bypass loppers to prepare fuel for the stove by cutting dry branches into segments about six to eight inches long and about 1/4 inch to one inch thick. I filled a three-gallon plastic bucket with as many such segments as would fit.
By the way, bypass loppers are the most effective tool that I have found for rocket-stove fuel-processing. I recommend that you buy the sturdiest pair of bypass loppers that you can find. The largest that I am aware of can cut limbs up to three inches in diameter. If you are aware of any bypass loppers with a larger capacity, please let me know at ThomasKChristianson at gmail dot com.
Initial Testing
It was a beautiful, sunny, spring day. The temperature was 50 degrees Fahrenheit. There was a steady breeze from the west.
I set up a table by the end of the pole barn, and placed two rocket stoves on it. One was the Coolfab Flaretop. The other was a Minuteman K stove that I had previously reviewed and had decided to keep for long-term use.
I took two empty #10 cans, and poured a half gallon of water into each. I then placed one of the cans on each of the stoves.
Then I opened the ash drawer of the Flaretop several inches and the fuel feed door all the way.
Next, I lit two Diamond Strike-a-Fire fire starters simultaneously. The wind promptly blew both out. I tried again with two more fire starters. The wind blew those out as well.
I relit two of the extinguished fire starters with a butane lighter. I then dropped one of the lit fire starters into the fuel feed tube of each stove. Next, I added one of the other two extinguished fire starters to each of the stoves. Then I added as many sticks on top of the fire starters as the combustion chambers of each stove would hold.
The smaller stove caught more quickly, but the bigger stove held far more fuel. I soon had fires whooshing through the chimneys of both stoves.
The flare top dispersed the heat more evenly over the larger cooking surface, while the K stove concentrated its heat into a smaller area. The more even heat distribution would be better for grilling, while the more concentrated flame would be more effective for rapid boiling. The cans on both stoves were steaming significantly within 15 minutes, but by then I also began to run out of fuel. It is surprising how many sticks a rocket stove can burn in 15 minutes.
I allowed both stoves to burn out over the course of the next 25 minutes or so. By that time, the fuel in each stove had been reduced to ashes, but the water in each can continued to steam.
A three-gallon bucket of sticks was not sufficient to fuel both stoves long enough to bring the water on them into a rolling boil.
Continued Testing
The next day was also beautiful and sunny. The temperature was 52 degrees Fahrenheit and sunny. There was a gusty breeze out of the northeast.
I used the bypass loppers to fill a five-gallon bucket with sticks.
I brought the flaretop rocket stove out by the fire pit near the pole barn. I used a hand truck to move it, since it was so awkward to carry.
I faced the air-intake shaft toward the breeze, and lit a Yooper Fire Starter with an ancient wooden match.
A Yooper Fire Starter consists of shredded paper strips coated with wax and encased in a wax-coated toilet paper tube. They are manufactured by Lakestate Industries of Escanaba, Michigan. They were a gift from one of the Elders of our church. He knows that I am a pyromaniac.
The match and its accompanying box were probably collectors’ items. The box is made out of paperboard thin sheets of wood with a Phillips 66 label on the top. The matchsticks have darkened with age, but they still light. I can’t remember where I got them, but I think that I have had them for about 35 years, and they weren’t new when I got them. I may have been a Philistine to so casually burn an artifact from the past. But at least I was a Philistine with a fire.
In any case, I dropped the burning Yooper Fire Starter into the fuel-intake and followed it with sticks until the combustion chamber was full. I put a #10 can containing a half gallon of water on the cooktop. Soon, the stove was drawing and flames were whooshing up the chimney.
It was almost lunchtime, so I popped a couple of hot dogs onto the grate next to the can. I continued to add fuel to the combustion chamber whenever there was space. Within 15 minutes, the water was simmering, and less than 10 minutes later, it was at a full rolling boil. The hot dogs also cooked quickly. Kari and I ate them wrapped in tortillas with ketchup, mustard, and French’s crispy fried onions. We continued to pop a couple of new hot dogs on the grate whenever we took a couple off. By the time the water boiled, we had consumed an entire pack of hot dogs, which we downed with a couple of bottles of water.
Conclusions
The Coolfab Flaretop Rocket Stove is an effective and versatile off-grid cooking solution. It is also fun. It is too heavy for typical mobile field use, but great for a fixed location.
Disclaimer
Coolfab loaned me a sample of their Flaretop Rocket Stove for testing and evaluation. Minuteman Provision Company had provided me with a sample of their K Rocket Stove for an earlier review. I did not receive any other financial or other inducement to mention any vendor, product, or service in this article.
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