Side by side comparison of two Sierra Zzip stoves showed small difference in performance. One had the double wall removed and was tested under exact conditions as the one with two walls. These tests and comparisons were conducted in January of 2007. Here is the information as to how the comparison was conducted and what the outcome was::
I've modified my zip stove to eliminate the double wall feature. I believe the heating of the fan forced air to be insignificant in the performance of the stove. The volume of forced air being the major contributing factor for the stoves ability to consume wood and provide high heat at a very fast rate.
I will perform tests using my old stove side by side with the modified version as time and weather permits.
First photo shows stove apart before cutting begins
Second photo shows cutting complete
Third photo shows stove re-assembled
Fourth photo shows stove in a bare bones state without upper rim attached. Stove has sufficient strength to be used without it in my opinion. Reduces weight by 18 grams/0.58 oz.
Fifth photo
shows cutting being made with a Dremel rotory cutting tool. Blade being used is a diamond impregnated cutoff disc. The stoves weight before modification was 326.2 grams/10.49 oz.
Modified stove(with rim) weighs 203.7 grams/6.55 oz.
Total weight reduction is 122.5 grams/3.94 oz.
The stove weights given are without fan assembly.
Fan assembly with battery weighs 110.5 grams/3.55 oz.
I've completely photographed the modification procedure and will post photos and instructions after burn tests are completed.
.007 stainless steel was used to cap off the shortend inner walls to maintain the flow of forced air through the row of holes located on the lower innermost wall as seen in one of the photos.
Enough people wanted titanium zip stoves so they made them using TI. If enough people want a single walled stove they'll make them that way, don't you think so? Less walls, less weight.
first photo shows harware http://img.photobucket.com/albums/v228/ ... ove010.jpg
second fphoto shows software http://img.photobucket.com/albums/v228/ ... ove011.jpg
I chose this type of Softerware so that each test burn can have the the same amount of fuel for each consecutive burn. I will count out the exact amount of each size fuel piece for each test.
I'm using fluffed cotton yarn for my tinder starter and the different size sticks as shown in the second photo. Yep!!!!! Clothespins all nice and kiln dried, tounge depressors, and craft sticks.
Water will be taken from the tap and test will be conducted in a calm/no breeze environment.(unheated greenhouse)
Are all of you in agreement that this is looking to be a fair way to go about testing my theory????
Any suggestions or questions?
update
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I found that the ss pots were not the same weight, one was 38 grams heavier, I swithced to using Kmart grease pots with outward rolled lip. Both were identical.
I attached machine screws to the body of the fan housing to create a stop for the lever that controls the volume of air going into the stove so that each test burn the air volume will be the same.
Assembled a thermometer stand to hold thermometer in pot while stove is heating. Long stemmed thermometer to keep my face away from hot stove and be able to monitor constantly.
All fuel and water has been weighed and are in individual containers ready to go
All materials are now in unheated greenhouse to be aclimated overnight in preparation for tomorrows tests. Three tests per stove will be made.
Tests will be made Saturday and results will be posted Monday
Any Comments? Anything I forgot?
machine screews to body
thermometer stand
fuel and water weighed
fuel in unheated greenhouse
Three tests for each stove have been completed.
After lighting, each stove was given one min. of time for tinder to ignite fuel and then pot of water containing two cups of water was placed onto stove. A clock was placed in a position to the rear and off to the side for photos to show min. into burn.
Temperature of water, fuel and air was at 35 degrees for the first two sets of tests. The temperature for the third set of tests had risen to 37 degrees.
No photographs were taken of the first set of tests
This first photo shows both stoves packed with same amount of fuel.http://img.photobucket.com/albums/ ... ove024.jpg
The next six photos show the progression of testing the unmodified stove during the second set of tests.
Photo one: 2 min. into burn
Photo two: 3 min. into burn
Photo three: 3 1/2 min. into burn
photo four: 5 min. into burn, water boils, flame starts to get smaller
Photo five: 6 min. into burn, steam comes out and raises lid of pot
Photo six: 6 1/2 min into burn shows fuel remaining
The next seven photos show the progression of the testing of the modified stove during the second set of tests.
Photo one: 2 min. into burn
Photo two: 3 min. into burn
Photo three: 4 min. into burn
Photo four: 4 1/2 min. into burn, boiling water pushes lid off pot
Photo five: 4 3/4 min. into burn shows boiling water and flame pattern
Photo six: shows remaining fuel
Photo seven: shows remaining fuel 1/2 min. later
The next eight photos show the progression of the third test done on the unmodified stove. Also shows how the fuel was packed into the burn chamber. The fuel was stacked around a clothespin in the center and later removed before lighting the tinder located at the base of the clothespin. The clothespin formed a hole that was used to put the butane lighter into to start the tinder as shown in one of the photos.
Photo one: shows lay of fuel and clothespin in center
Photo two: filled with fuel with clothespin in middle
Photo three: shows butane lighter in center hole to show how stoves were llit
Photo four: 3 3/4 min. into burn
Photo five: 4 min. 10 sec. into burn, temp at 150+ degrees
Photo six: 4 min. 20 sec. into burn
Photo seven: 5 min. into burn, temp. at 200 deg.
Photo eight: 6 min. into boil water boils
The next three photos show the progression of the third test done on the modified stove. Water boiled at 4 1/2 min.
Photo one: 2 min into burn
Photo two: 2 min. 36 sec. into burn shows flame pattern
Photo three: 3 min. into burn
The next two photos show cleanliness of stoves before and after test.
Photo one: before tests http://img.photobucket.com/albums/v228/ ... ove009.jpg
Photo two: after tests http://img.photobucket.com/albums/v228/ ... ove049.jpg
Boil times for each stove:
Unmodified: Test one: 5 1/2 min.
Test two: 5 min.
Test three: 6 min
Modified: Test one:4 1/2 min.
Test two: 4 min.
Test three: 4 1/2 min.
The Results: The Modified stove outperformed the Unmodified.
I like your vacated clothespin lighting cavitiy 
