Category Archives: Gear

The Ghetto Bank

A little while ago, the first battery of my trusty Makita power drill died, and the second battery is in not that good shape either, nothing wrong with the drill itself though.

A little shopping and googling tour revealed that a spare battery for my drill is almost as expensive as a brand new drill with two batteries. So, if I wish to replace both of my drill batteries with new ones, the most ecomical way to do that is to buy a new drill set, and discard the drill. In my honest opinion, that is beyond wrong!

Therefore, I had to try to find some alternative way to power my drill, and to resist the Man.

Well, what is a drill battery?

It is some metals and electricity producing chemicals wrapped into a plastic shell, carefully designed to be incompatible with anything but one particular brand and model of a drill.

How is the battery attached to the drill then?

Naturally, with at least a pair of complicated clips, incompatible with any device known to man, except one particular brand and model of a drill.

Well then, how is electricity transferred from a battery to a drill?

Via two pieces of metal, of course!

So, the world is full of cheap batteries and drills, but only very expensive ways to attach them together.

There are no complicated control circuits or anything like that between the basic drills and the batteries. Therefore, the only possible reason for the ridiculous prices of the spare batteries must be an international conspiracy by the secret order of evil incompatibility design engineers. (Some say that they may have the influence of the Stone cutters and the No-Homers, combined!)

OK, which batteries to use in an attempt to resist the Man?

The main criteria, price and availability, leave only one option; 18650 Li-ion cells from “dead” laptop batteries.

Most of the modern households have at least one “dead” laptop battery, and most of the people are only happy if someone takes out their trash.

I happened to have an old HP laptop with a battery that was able run the computer for only some tens of seconds, and, according to the info on the screen, refused to be charged above 1% of the total capasity. So. I carefully cracked open the battery case with a knife and a screwdriver. Carefully, because there is a true risk of turning a Li-ion cell to a torch by puncturing it and causing an internal short circuit.

Next I separated the six cells by ripping off the connecting strips of metal, and measured the voltage from each of the cells. From a battery without any signs of life in last five years, I did not expect too much, but to my great surprise, the voltage in all of the cells was between 3.4 and 3.5 V, i.e. they were all “empty”, but not dangerously over-drained. Depending on the source, the dangerous level of voltage, leading to irrepairable damage, is somewhere around 2.5 V (The protection circuit cut-off value varies between 2.2 and 2.9 V, depending on the manufacturer.)

So, it was possible that my batteries were not quite dead yet, and I continued my project by testing whether the batteries could still be charged. Problem with Li-ion cells is that in addition to being dangerous in low voltage conditions, over charging can, and will, transform them to a torch and/or a low power hand grenade. In order to avoid unwanted fires or explosions, most of the commercially available Li-ion batteries come with an in-built protection circuit, which takes care of over and under voltage situations. However, in case of laptop, and many other battery packs, a single protection circuit protects the whole package, and individual cells are un-protected, prone to explode or catch fire in inexperienced hands. To keep my house, eyes, hands, and other body parts intact, I test-charged the cells one by one with a protected Li-ion battery charger in relatively fire proof environment, never leaving a charging cell alone (just staying far enough from possible shrapnels). After a good two working days of charging, all of the cells were happily charged to the chargers cut-off level of 4.2 V. No smoke, no fire, no explosions, and the cells seemed to keep their charge pretty well, at least without any load applied. After about two weeks on the table, the voltage of the cells varied between 4.18 and 4.19 V. Then it was time for some capasity testing; all of the presumably 2200 mAh cells were able to run a 10 W led lamp for 40 minutes ( to avoid over dis-charging the batteries, I did not continue any further). After the test all of the cells still had at least 3.6 V in them, and although the test was not very accurate, it proved that the cells still had decent capasity in them.

In the end, I came to a conclusion that all of the cells from my dead laptop battery were in good working order, and that the failing part of the original battery pack must have been in the external circuit board, not in the cells.

Now I had six 2200 mAh cells to play with, and I decided that instead of just trying to replace a battery for my power drill, I’d try to build a bit more versatile power pack with a smallest possible budget, a true ghetto bank.

Well, the cells I had, and they were free. I also had a container, a 0.5 liter plastic freeze box from my kitchen (value about 40 cents), and some short pieces of wire, scrap plywood, screws and such from my scrap box (combined value about 10 cents). The only things I had to buy were the trays to hold the cells, and the protection circuit for my ghetto bank. I ordered those from one of the Chinese web shops (Trays 4.34 $, protection circuit 2.74 $, including shipping).

The total cost of the basic ghetto bank was less than 8 $, that is about 7 €. For the subsequent connecting gadgets, I was prepared to spend anything up to 4 $.

Building the ghetto bank was relatively easy. First I wired the trays so that they can be used either in 3S1P or 3S2P configuration, and attached the trays to a small piece of 4 mm plywood. Then it was time to solder six pieces of wire to the protection circuit board. With proper tools that is not difficult at all, but it was quite tricky to handle microscopic connections with my snow shovel size soldering iron. Miraculously, the circuit board survived the soldering, and I was able to cover the connections an loose wires with generous amount of hot glue. As universal power outlet, I used two strips of metal attached to the plywood frame.

The whole package fit perfectly into my sophisticated tacticool container, a 0.5 liter freeze box. A freeze box is actually very good power bank container. It is very compact in size, it gives pretty good physical protection, it is practically water proof, and if you happen to fall from a boat, your ghetto bank floats!

Weight of the whole thing with six cells is 410 grams (about 14.5 oz), and with three cells 280 grams (about 10 oz).

Additional equipment I’m going to carry with my ghetto bank are a cigarette lighter plug with 5 V USB output, a small universal plug, which fits to the charger of my video camera, and a pair of jaw clip test wires to connect everything together. Combined weight of these is 40 grams (about 1.4 oz), and the combined cost of them is 1.2 $, which brings the total price of the ghetto bank to a whopping 8.9 $. Even if we add a price for all of the consumables, such as 2 bars of hot glue and 5 cm (2 inch) of soldering wire, we can still safely declare that it is possible to build a 45 Wh power bank for less than 10 $. (If you are on a really tight budget, you can make your own battery trays and reduce the total cost to about 5$).

Then to the testing of the ghetto bank.

Initial readings from the multimeter were healthy 12.5 V with 3S2P as well as with 3S1P indicating that the wiring and the connections were all good.

Tests with plain wires, various plugs, and 12 V to 5 V USB converter were all successful, Tablet, Phone, action camera, and video camera were easily charged, and 25 W lamp shined nice and bright. Everything else but the original target, the power drill, worked beautifully. When I connected the ghetto bank to the drill, the drill gave some signs of life, but refused to catch any rpms. Suspecting the protection circuit being a bit over protective, I bypassed it and connected the cells directly to the drill, and what do you know, the drill was spinning without any trouble.

After a little study session, it became obvious that due to the protection circuit’s maximum continuous operating current of 2.5 A, the max output of the ghetto bank with fresh cells is about 31 W (12.5 V X 2.5 A), where as the Makita drill would prefer 35 W. Oh, so close!

Well, my bad, but I cannot be that sorry. After all, I managed to build a dirt cheap power bank good for a lot of things, and if I can find a protection circuit with maximum continuous operating current of 3 A or above, for another investment of 8 $, building a drill specific battery is a piece of cake.

Finally, to another great feature in the ghetto bank, relatively flexible charging.

The ghetto bank can be charged as a whole pack using practically any power source providing 12 V DC, including automobile cigarette lighters. The protection circuit manufacturer recommend 12.6 V meaning that a cigarette lighter with occasional 14-15 V is a bit of an overkill, but the charging seems work with them anyway.

Another way to charge the ghetto bank is to use a proper Li-ion battery charger for individual cells. This way it is possible continue using the ghetto bank with three cells while the other three cells are charging.

In conclusion, I can say that I’m pretty proud of being able to build a versatile, flexible, small, light weight, water proof, floating, and butt ugly ghetto bank with almost zero budget.

If you are familiar with the Li-ion related risks, poor, and adventurous, I can strongly recommend the ghetto bank design. All of you normal people should stay away from it.

DIY JR27 Sled

About 15 years ago, I found instructions of how to make a sled with household tools and easily available materials. Already then, the internet was filled with stupid, more stupid, and impossible instructions of pretty much anything. Therefore, I almost ignored this “too good to be true” sled plan. Fortunately, next to the instructions there was a picture of the guy behind the plans, and I realized that I knew him. He was my former teacher from the department of genetics at the university of Oulu, and I had never heard any BS from him, or of him. Therefore, I decided to try to build his Ultimate JR27 sled. I followed his instructions to the last detail (except for the canvas belt, which I replaced with a leather one), and the end result was an absolute success. (Unfortunately, the original plans are only available in Finnish, but at his pages you can find some very nice drawings and measurements of the sled.)

Since building my sled, I have used it in every single winter trip to our hunting cabin hauling food, fuel, and clothing with unbelievable ease. In fact, in the last 15 years I have learned to not pay much attention to the amount of stuff I pack into my car during the winter time. Why bother? My sled can handle that.

This begins to sound like an average internet review of some worthless gadget that has been tested by reading the package insert and walking the gadget around the garden once or twice. Where is the real field test?!

Fortunately, this particular type of sledge has been tested. In 2004, a guy named Erkki Lampen skied from south coast of Finland to the northern most border of the country. It took him a good two months and 1200-1300 km (750-800 miles). He hauled his 50-60 kg (110-140 lbs) load with a home made JR27 sled. During his epic journey, he kept an online diary with daily text messages, and I was lucky enough to notice that and follow his whole trip. According to his diary, especially for the first hundreds of kilometers in southern Finland, he dragged the poor sled in not so good snow conditions, sometimes practically on gravel. Due to the treatment of the sled, after about 800 km of skiing, a runner of the sled broke, and it had to be replaced. No other serious problems during the trip. After the trip he wrote that if he would do the same thing again, he would use 15 mm runners instead of the original 8 mm, and replace the 10 mm fiber glass tubes with 15 mm tubes.

As a conclusion from his experiences, and mine, I would say that the JR27 is pretty well tested, and if you are going to drag ridiculous loads on gravel and steep hills, thicker runners and pulling bars are recommended, but if you rank yourself mortal, the original design does its job very well.

As promised on the video, here are some building instructions:


For the sled:

4 m (13 ft) 4 to 5 in wide, 12 mm (½ in) thick board

0.5 m (20 in) 2X2 in wood

40X200 cm (16 in X 7 ft) sheet of 1 to 2 mm (1/24 to 1/12 in) high density polyethene (HDPE)

Two 180 X 2 cm (6 ft X 4/5 in), 8 to 15 mm (1/3 to 5/8 in) thick strips of HDPE

For the pulling gear:

Two 2 m (6 ½ ft) long 10 to 15 mm (2/5 to 3/5 in) glass fiber tubes

1 m (3 ft) 10 to 15 mm (2/5 to 3/5 in) id rubber tube (coolant tube from a car)

One belt

For covering and binding the cargo:

1.5 X 2 m (5 X 7 ft) tarp

5 m (17 ft) of 6 mm (¼ in) bungee cord

4 to 5 pieces of 10X2X1.5 cm (4X4/5X3/5 in) wood

For attaching everything together:

Duct tape

4 hose clamps

Some screws, rivets, staples, and nuts and bolts


Work flow:

Cut the rear panel from the board symmetrically so that the top and bottom lengths are 42 and 32 cm (16 ½ and 12 ½ in), respectively.

Cut the front beam from the 2X2 in wood to the same angle with the rear panel so that the top of the beam (the longest side) is 41 cm (16 in).

Cut the side panels to about 170 cm (6 1/2 ft).

Shape the side panels as seen in the video.

Drill the holes for the screws (2 for each corner).

Screw the frame parts together.

Plane the bottom edges of the side panels.

(If planning to paint, do it now)

Attach the HDPE sheet to the front beam with screws and washers.

Place the HDPE strips against the bottoms of the side panels (HDPE sheet between the runners and the side panels).

Drill holes for the screws (12.5 cm (5 in) intervals) using a thin drill bit.

Drill sink holes for the countersunk screws with a bit thicker drill bit .

Attach the runners and the HDPE sheet to the side panels with the countersunk screws.

Attach the rear end of the HDPE sheet to the rear panel using screws and washers.

Cut four 20 cm (8 in) pieces from the rubber tube.

Drill holes to the side panels and attach one tube to the each side of the sled using two bolts and nuts per tube.

Rivet remaining tubes to the belt so that they are evenly on both sides.

Wrap the ends of the fiber glass tubes with 2 to 3 layers of duct tape.

Slide the fiber glass tubes into the rubber hoses and secure with hose clamps.

Staple a piece of tarp close to the interior bottom edge of the side panels.

Thread the bungee cord through the holes on the side panels and the wooden locking pieces.

Pack the sled and go.

Mini Trangia and winterizer at -32.6 C

About a year ago, I tested my home made winterizer for the Mini Trangia alcohol stove at –25 C (-13 F). To my great surprise, my “not good at really cold weather” Trangia managed to boil 500 ml of +4 C (+39 F) water in about 7 minutes, mainly due to the help provided by my DIY winterizer.

Since then, it has been ridiculously warm, and now was my first opportunity to try to find the limits for an alcohol fueled stove.

So, this is how it went. First, I left the stove and the fuel outdoors at -32.6 C (-26.7 F), and 500 ml of water into the fridge for overnight.

In the following morning, I loaded sthe stove and soaked the wick of the winterizer with -32 C alcohol (Note to self: Do not spill it on to your fingers. It is damn cold!). Despite the syrup like behaviour of the cold alcohol, lighting up the alcohol soaked wick was very, very easy. However, due to the 5 m/s wind, it took albout 13 minutes to bring the water to boiling. Therefore, I repeated the experiment using a simple windscreen made out of fire retardant fabric.

With the windscreen, the boiling time was reduced to 9 minutes and 40 seconds.

As conclusion, with a proper protection from the wind, an alcohol burning stove (with DIY winterizer) still works beautifully at -32 C !

As soon as the good old -40 to -50 winter days (hopefully) return, I’ll test and report whether there really are any limits for my little Trangia stove.

How to tar wooden skis

When I want to exercise during the winter, I take my wonderful pair of cross country skis, and hit the tracks maintained by my beloved home town. My skis are very, very light weight, made of glass fiber, and some “nanotech” thingies, which I don’t even try to understand. I just love those skis. They are absolutely perfect for pleasant 10 to 25 km (6 to 15 miles) exercise trips on man made tracks. However, when the man made tracks end, they are also absolutely useless.

For deeper snow, one needs skis wide enough to carry the skiers weight, and, in most of the situations, short enough for convenient handling. For that purpose, whether one wants to conquer the south pole, or just to have a pleasant week long deep snow trip, there are plenty of carbon fiber – titanium composite, honeycomb structure wonders available for only a few hundred euros/dollars.

Well, since my off track skiing is limited to hauling stuff to our hunting cabin, and occasional hunting or ice fishing trips, my choice of off track skis for the last 30 years, has been wooden military skis (Swedish army surplus) worth of 10 euros/dollars (including bindings).

For the last three decades, my 210 cm long, and 10 cm wide (7 ft, 4 in, respectively) wooden skis have been loyal partners in many, many winter trips in various snow conditions, and I’m planning to use the very same pair of skis for the next three decades as well.

To make a pair of wooden skis last for 30 (or 60) years, there are couple of things to remember. 1) The wood has limited flexibility. If you are aiming for the olympic gold in moguls, for training, use skis made of some other material. 2) To maintain the original flexibility of the wood, store your skis outdoors or in cold storage space protected from the direct exposure to the sun. 3) Tar your skis.

There is an ancient Finnish saying: “If sauna, booze, and tar does not cure it, it’ll kill you.”

And what is good for a man, must be good for skis too. Well, sauna may be beneficial for the skis in some situations, and some booze may delight the skier, but tar is absolutely essential for the well being of wooden skis.

OK, why, and how, to give tar to your wooden skis?

First, Why? What does the tar really do?

First of all, the tar protects the wood from water. It has been used for that purpose for thousands of years, and not only for skis. For a very long time, tar was the most important export product of Scandinavia and Finland. It was used for all imaginable items made of wood, including wooden ships. For centuries, the British Royal Navy was the biggest customer of the nordic tar industry.

In addition to protecting naval vessels from water born damage, tar preserved woods original spring like nature. After the end of wooden ship era, and developments in chemistry, tar slowly became less and less important in industrial and household use, but it still is the best thing that can be applied on to wooden skis. It protects the skis as well as it used to protect huge sail ships, but it also acts as an universal ski wax. No other material, as far as I know, has those beneficial properties so perfectly combined.

Then, How?

First, find some good quality tar made from pine trees (should be available at the local hardware store, if not, try some all natural boutique for tree-huggers). Next, find a hot air gun or a blow torch. Then, the only thing missing is a tool to apply the tar. For that, a perfect thing is an old tennis sock or any other cotton rag.

Start the tarring project in a warm day, or by bringing the skis indoors. (if you are doing this indoors, protect the floor. Tar is messy and sticky stuff.)

Pour some tar onto the bases of the skis (as seen on the video). Then heat the tar with the hot air gun or with the blow torch (if you are using the blow torch, do it outdoors). Spread the tar with a cotton cloth (an old tennis sock). Heat the tar again, and rub it in with your old sock (Be careful, not to burn your fingers or to melt the floor cover.)

When the skis have absorbed all the tar, leave the skis indoors for the final drying for few days (or place them into the sauna for few hours), and you are ready to go for the next 100-200 km (65-130 miles).

Now that I have convinced you about the tar’s superiority against anything else, and you have carefully tarred your skis, I must warn you that for the first couple of kilometers, after newly applied tar, the glide of the skis is somewhat questionable, but after that, the skis should serve you really well for the next 200 km at temperatures from 0 to -20. For warmer weather and wet snow, it is a good idea to have a candle stick in your pocket, and when the wet snow begins to stick to the skis, rub some candle paraffin on top of the tar, and just keep on skiing.

Traditional wooden skis are comparable to the Jeep among cars. You wouldn’t race your Jeep against Ferraris or Hummers in their own fields, and there are plenty of better cars for everyday commuting, but if you want to do a little bit of everything with one car, Jeep is not the worst choice.


DIY Walking Trailer

For couple of weeks in a year, the partially frozen or flooding river makes it impossible to use a boat, and there is not enough snow to haul heavy stuff to our hunting cabin using a sledge. Being well prepared in advance, those few weeks usually are not a problem at all, but it would still be nice to be able move things by some easier way than by making several round trips dragging a fully loaded backpack. Therefore, I decided to build a cheap walking trailer, not weighing more than 10 kg (22 lbs), hopefully capable of handling at least 50 kg (about 110 pounds) load on an uneven terrain.

For serious hikers there are some very nice monowheel trailers commercially available. Good monowheel trailers can be pulled through relatively difficult terrain. Problem with the mono wheels is that in order to maintain good balance of the loaded trailer, both the frame and the pulling gear must be made of very rigid materials, which tend to be ridiculously expensive and difficult attach to each other with the tools that can be found in every household.

Since I’m not planning to drag a trailer in a pathless forest, and I do not have equipment to weld aluminum or laminate carbon fiber, I ended up with a plan to build a simple two wheeler using no more than 70 euros for the whole project.

The original design was to build a flat 0.5X0.5 m (20X20 in) deck on top of two 12 inch wheels, and connect it to some military surplus harness using two rigid poles.

First I went to a local bike shop and asked the price for the front wheel of a children’s bike. When a cheap bike costs less than 100 euros, I was a bit shocked to hear that just a front wheel (no tires included) was 35 euros. It seemed like just the wheels would break my budget. So, I walked out of the shop and googled the local flea markets. After a quick search, I found a nice little bike for 20 euros. Instead of buying another bike, I decided to use both of the bikes wheels for my trailer project. The gearwheel and the brake bits were not that difficult to remove from the rear wheel, and I didn’t believe that the small difference in the width of the axles between the front and the back wheels would cause too much trouble (which later proved to be true).

For the frame of the trailer I used two 42X42 mm (1 2/3 X 1 2/3 in) 0.5 m (20 in) long pieces of wood (local hardware store didn’t bother to charge for those). To make the frame pieces wide enough to accommodate the fork structure for the wheels, I glued three pieces of 2 cm (4/5 in) thick wood to the both sides of both of the frame pieces.

For the forks, I used four 25 cm (10 in) long pieces of 3 mm (about 1/8 in) thick flat iron. The supporting structure was made from 2 mm (1/12 in) flat aluminum. Two of the flat aluminum bars were left a bit longer than the others to support the rear end railing made of a 6 mm (¼ in) threaded rod covered with a plastic tube.

Then I finished the deck with 12 mm (½ inch) wooden bars and supporting pieces of flat aluminum.

For the pulling gear, I happened to have a 2 meter (about 7 feet) piece of round 20 mm thick (about 4/5 inch) wood. To reinforce the pulling bars, I inserted them into 20 cm (8 inch) pieces of steel tube, and drilled the necessary holes for the assembly.

Since I’m going to be the sole user of the trailer, I attached the pulling gear in the fixed angle. For a multi user version, one must design some kind adjusting system. At this point it was absolutely essential to measure the angle very carefully so that the pulling bars are at comfortable level on your waist and that in the same time the deck of the trailer is level to the ground.

After some trials and errors, it became obvious that for the required rigidity, in addition to the attachment to the frame, the pulling gear needs two supporting points. For the supporting structure, I bolted two pieces of flat aluminum between each of the pulling rods and the frame of the trailer.

For the actual pulling harness, I combined a surplus German army military belt (5 euros) with a surplus Alice suspenders (a copy of Alice made for the former Yugoslavian army, (3 euros)). The pulling harness does not have to be German-Yugoslavian, any rugged, relatively comfortable harness works equally well. (I say relatively comfortable because it is truly surprising how small amount of weight or pulling actually comes to your shoulders or waist.)

To attach the pulling bars to the harness, again after some trials and errors, I decided to drill a small hole through the pulling bars, push some paracord or equivalent through the hole, wrap it around the pole couple of times , tie a loop to the paracord, and use the loops to attach the bars to the harness.

Of course it is possible to design more or less “tacticool” attachment systems, but based on my experience, the paracord loop system is easy to make, adjust, and if necessary, to fix in the middle of nowhere. A two meter (about 7 ft) piece of paracord, which can be used for many other purposes in camping conditions as well, is pretty much all of the spare parts one may need to fix the pulling gear.

I made my walking trailer couple of months ago, but I didn’t want to publish any instructions before some test rides were completed. Therefore, after some initial short tests, I took a nice little 55 km (about 35 miles) stroll with a friend of mine, loading the trailer with some 30 kg (about 65 lbs) of stuff. (The stuff was bound to the trailer with cheap bungee cords). After 55 km on asphalt, dirt roads, and some relatively uneven hiking paths, there were not to many things to complain about.

The trailer was nice, easy, and surprisingly light to pull. 12 inch ground clearance was quite enough, and the whole load stayed where it was supposed to stay through the whole trip.

The only thing I would have changed was the length of the pulling bars. In my original design, the bars ended to my waste, and occasionally it would have been nice to have some handle bars in front of me to steer or support the trailer through tight spots on the path. Therefore, I decided to replace the original bars with the new, about 40 cm (15 inch) longer ones.

Before changing the bars, it was time to test the real weight handling capacity of the trailer. For that, I had an opportunity to haul some 25 kg (55 lbs) bags of concrete on an uneven terrain. 50 kg (110 lbs) was easy. The same was true with 75 kg (165 lbs). 100 kg (220 lbs) was surprisingly light and easy to haul, but on one, kind of a sharp bump, both of the pulling bars cracked. No other damage to the trailer though.

The last test proved that my simple cheap home made trailer is capable of handling a lot more weight that I would ever imagine trying to make it handle, and that the weakest part of the trailer was the pulling bars (which I was going replace anyway).

Based on my experience from the trailer project, I can pretty safely say that it is possible to build a decent walking trailer weighing less than 9 kg (about 20 lbs) for dirt roads and relatively easy hiking trails using cheap materials and household tools for less than 70 euros.

List of parts:

1 m (40 in) wood (42 X 42 mm (1 2/3 X 1 2/3 in)) 2 € (usually for nothing)

4.5 m (15 ft) wood (42 X 12 mm (1 2/3 X ½ in)) 6 € (or free from discarded hat shelf)

Six small pieces of wood (20 X 42 X 100 mm (4/5 X 1 2/3 X 4 in) (ask any carpenter or hardware store for free)

two 12 inch Wheels (used children’s bike) 20 € (70+ € as spare parts for big spenders)

Two 140 cm (55 inch) Pulling bars (22 mm (7/8 in) diam.) 5 € (Broom sticks are good for this)

1 m (40 in) flat iron (3 X 30 mm (1/8 X 1 3/16 in)) 2 €

6 m (20 ft) flat aluminum (2 X 20 mm (1/12 X 4/5 in) 24 €

50 cm (20 in) steel tube (20 mm (4/5 in) inner diameter) 1€ (or abandoned piece from a coat closet)

50 cm (20 in) threaded rod (6 mm (¼ in) diameter) 1 €

50 cm (20 in) plastic or rubber tube (6 mm (¼ in) inner diameter) 50 c

Surplus military belt 5 €

Surplus military suspenders 3 €

Nuts, bolts, wing nuts, screws, and washers 3 €

The final cost of my project was 63 € 50 c, which, in my opinion, was quite reasonable price for a very usable walking trailer weighing less than 9 kg (20 lbs). With any luck with friends and relatives with small children, and the content of your scrap boxes, the costs can easily be less than 40€, and even if you start with absolutely nothing and buy everything from the shops, it is very difficult to use a lot more than 100 € for the whole project.

Using a once frozen water filter may kill you

Modern hollow fiber water filters are true technical wonders with their ability to get rid of bacteria, protozoa, and even viruses from unbelievably large amount of contaminated water. After reading the descriptions of some of the best filtering devices in the market, one easily gets impression that problems with dirty water are ancient history, at least for the wealthy westerners. However, somewhere from the manufacturer’s website you may find a following kind of warning: “After iniatial wetting, do not expose your water filter to temperatures below freezing. There is no definitive way to tell if a filter has been damaged due to freezing.”

I have heard of several occasions where a hiker has ran into trouble with a clogged water filter due to cold weather, “but after I kept the filter inside my jacket for awhile, everything was OK, and the filter worked again.”

No, everything was not OK! After the thawing, the water filter did let the water flow again OK, but most probably, it did not any more do its job as it should have, as the freezing process itself had destroyed the filtering structures.

And here is what happened. (Warning: light science content!)

As you may remember from high school science class, water has some interesting properties.

Water has the highest density, pretty close to 1g per cubic cm (0,999973 g/cm3, to be exact), i.e. it is heaviest, at +4 C temperature. When water freezes, its density decrease to about 0.917 g/cm3, i.e. it becomes lighter than liquid water. One can easily test that by dropping an ice cube into a glass of water, and see whether the cube floats. The reason why the ice cube floats is in the formation of ice chrystals, which need more space than free water molecules, and therefore when a gram of liquid water happily fits into a single cubic centimeter of space, a gram of ice needs about 1.09 cubic centimeters. And the ice truly takes its space. There are some variables in the behavior of the ice, but it can be pretty safely said that in standard natural situation, freezing water applies some 100 Mpa pressure against anyone or anything trying to resist it (that is about 1000 kg/cm2, and about 14500 psi). So, no wonder that boulders crack and water pipes burst during cold spells, and it is not difficult to imagine what happens to the tiny filtering pores and the tubes in a water filter filled, or even partially filled with freezing water. Yes, they crack, and even if the water flows beautifully through the filter after thawing, the filter is no longer filter, but a sieve, no longer capable of filtering harmful bugs.

The internet is full of “expert” advices of how to test whether your water filter is OK after freezing, and each advice is, if possible, even more stupid than the previous one. For example, one rather common “expert” way to test the filter is to try to blow air through the filter against the direction of the water flow, and according to this wonderful advice, if you cannot blow the air through the filter, your filter is in perfect working condition. OMG! The only thing the blow test is good for, is to check whether the filter is still capable of filtering bugs such as ants or cockroaches. Size of bacteria is typically about 0.5-5 micrometers, and there is no way that someone could detect some 10-100 micrometer cracks by blowing air to the filter, where as our friend, the bacteria, which used to stay behind the filter’s 0.1 micrometer pores, now happily swims through the giant cracks.

So, please, if you even suspect that your wet water filter could have been exposed to freezing temperature, get rid of it, buy a new one and be 100% sure that you know where your water filter has been at all times!

In my honest opinion, a warning about the dangers of freezing the water filter should not be hidden somewhere in back pages of companies web sites, but written with flaming letters (with proper explanation of hows and whys) at the home/front pages of all of the water filter manufacturers!


FYI, here is a screenshot from FAQ:

Screenshot from 2015-03-04 22:21:15

Mini Trangia DIY Winterizer test at -25 C


A little while ago I made a pre-heater for my Mini Trangia stove. Initially, I was able to test it at -12.5 C temperature, and was pretty happy with the results (500 ml of water from +4 C to boiling in 7 minutes and 39 seconds).

Now, the winter finally seems to kick in, and it is time to test what the winterizer is good for.

To begin the test, I left the Trangia stove and a bottle of fuel outdoors for overnight, and some water into the fridge. In the morning, the temperature was -25 C. Not as cold as I was hoping for, but so far the coldest weather during this winter anyway. So, I filled up the stove, and soaked the glass wool wick of the winterizer with -25 C alcohol, and stroke a match. The ignition was kind of lame, but easy and instantaneous anyway. Next I poured 500 ml of +4 C water into the Trangia pot, placed it (with the lid on) on to the stove, and prepared myself for a long wait.

To my pleasant surprise, after mere seven minutes and six seconds the water was boiling merrily. That was over 20 seconds faster than in my first test run at -12.5 C! How could that be? When comparing the conditions of the two tests, in addition to the difference in the temperature, the only remaining variable of any significance was the wind, which, during the first test wasn’t particularly strong, but strong enough to slightly disturb the flame and to cool down the pot a little bit, whereas during the second test the wind was hardly noticeable.

The test results confirmed the general belief that a good wind protection is essential for successful cooking with camping stoves, but more importantly, the results proved that my DIY winterizer works beautifully even at -25 C temperature. I can’t wait for the arrival of really cold weather to test the winterizers limits (if there are any).

Melting snow with the Mini Trangia at -8.2 C

Unpressurized alcohol stoves are not suitable for melting snow. That is one of the most common statements one can find from a countless number of camping stove reviews.
Well, I happen to have a Mini Trangia, I don’t have funds to get any nuclear powered wonder devices, and where I hike, the most convenient way to get water, about six to seven months of the year, is to melt some snow. Therefore, I absolutely had to test whether my poor little Trangia really is useless for melting the snow.
The test conditions were not very wintery, only -8.2 C below freezing, but on the coolish side anyway, and enough snow to perform the test. (I’ll repeat the test in colder conditions as soon as it gets cold, however, the weather forecast for the next 15 days is somewhat summery, from +1 to -5 C, so this is the best I can do right now).
Alcohol is a bit tricky fuel in cold environment, therefore, I used my home made winterizer for the Mini Trangia in my test. With the winterizer, the fire was easy to light up. Then I loaded the mini Trangia 800 ml pot with fresh snow, and started cooking, or melting in this case. I kept filling up the pot with more snow till I had 500 ml of water. To get half a liter of water from snow, in -8.2 C temperature, took 6 minutes and 30 seconds, which, in my opinion, is not bad. Then I placed the lid on top of the pot and continued cooking. 8 minutes and 38 seconds later, I had 500 ml of boiling water, not bad either.
Total time from snow to boiling was 15 minutes and 8 seconds, which is not lightning fast, but, again in my opinion, not ridiculously slow either. I have had slower boiling times in the middle of the summer (in windy conditions, without the winterizer, of course, and without the lid, though).
Of course, most of the multifuel burners, and some gas burners are a lot quicker, but, based on my test, announcing that one cannot melt snow with unpressurized alcohol stove, is wrong.
In -8.2 C, melting snow with the Mini Trangia is absolutely possible, and not even that slow.

Longer report of the Mini Trangia’s behavior in various conditions will be published sometime in the future.

1-piece Hobo Stove


Although there are not too many actual hobos wandering around these days, the internet is full of instructions of how to make more or less sophisticated hobo stoves, and there are some good reasons for that: Hobo stoves are fun to make; no need for expensive or complicated materials or tools, quick to test and to modify, and if everything goes wrong, just throw away that cheap can and try again. A good hobo stove is also pretty capable camping stove; no need to carry any fuel with you, especially during the summer time, when relatively dry sticks, twigs, and pine cones are easily available. Although longish simmering with a hobo stove is somewhat labor intensive, for a quick boiling job, it is an effective tool; boiling 500 ml of water can be done in less than four minutes in most of conditions. And additionally, during a forest fire warning, in which all open fires are prohibited (at least in some countries (including mine)), placing a piece of sheet metal underneath the stove, officially makes it a contained camping stove, which is OK to use, even during the forest fire warning.

Those reasons were good enough for me to try to make my own hobo stove. The requirements I set for my stove were: Low price, easy to make, simple structure i.e. no moving parts, and not too heavy.

All of the set requirements were met by a stainless steel cutlery stand, which I happened to find at a local supermarket for 3,90€, (Price requirement – check). Due to its original purpose, the stand was full of evenly spaced holes, so, the only thing to do to convert the stand to a stove, was to cut three 3X6 cm pieces from the top edge of the stand. After about 15 minutes of work with a hack saw (could be done in 2 minutes with Dremel or equivalent tool), my 1 piece hobo stove was ready to run (easiness and simplicity requirements – check). Most of the hobo stoves I have seen, have some kind of legs to take care of the air flow through the bottom of the stove, and some kind of, usually detachable, structure to act as a holder for pots and pans. Finding fist size stones for legs of a stove has never been a problem in my hiking grounds, so, I skipped the legs. By cutting the three pieces from the rim of the stand to create a chimney effect, the remaining three pieces of metal formed a perfect stand for pots and pans, therefore, I had no need to design any additional structures to do the job, and, that was a pure accident, the diameter of the stove happened to be exactly 10 cm, which makes my hobo stove compatible with the pot from my Mini Trangia camping stove. The weight of my hobo stove is about 400 grams, which means that it is not the lightest of all of the hobo stoves, but on the other hand, considering that I don’t have to carry any fuel with me, it is not that heavy (weight requirement – check), and stainless steel stove with 1 mm thick walls is practically bullet proof, and it looks good too. 😉 This one should last for a life time.

After a quick field test, I can say that I’m pretty happy about the results; The stove is easy to use, easy to feed (although for feeding with the thickest and longest sticks, or the largest pine cones, one has to lift off the pot), and very effective.

If I’d have to complain about something, I’d say that the efficiency of the stove would probably improve by blocking the two top most rows of the holes. However, blocking them would increase the weight of the stove, cutlery stands without the top most holes are not to be found easily, and the stove works pretty well as it is.

In conclusion, I can strongly recommend my hobo stove as a trusty 1-piece hiking companion, or as a starting point of long term hobo stove development hobby.

More info about camping stoves can be found from:
Zen Backpacking Stoves


DIY winterizer (pre-heater) for Mini Trangia


One of the most common complaints about alcohol burners is that they are difficult to light up in freezing temperatures. To solve this winter time problem, Trangia sells winter attachment kit for larger Trangia stoves (series 25 and 27). It contains an aluminum plate, which prevents the hot burner sinking to the snow, and a pre-heating cup with some fire proof sponge, which, when soaked with alcohol, acts as a wick underneath the actual burner. Unfortunately, the pre-heating cup of the kit does not fit into the Mini Trangia system. Therefore, one must figure out an alternative way to pre-heat the Mini Trangia. Fortunately, the Mini Trangia has its own, in-built pre-heating cup, the aluminum burner holder/windscreen. Between the burner holders wall and the burner, there is just right size space for home made glass wool wick. Well, the wick does not require any making. Just place the burner on its place, and stick small pieces of glass wool loosely around it. Fill up the burner. Then soak the wool with alcohol, light it up, and voila’, the pre-heater for the Mini Trangia is up and running. Glass wool works pretty well as a wick. Fire seems to damage it a little bit, and it may be necessary to replace the wick after it has been used for couple of times, but the glass wool is very light weight, and the amount of it needed for the pre-heater is very very small, so, that should not become a problem. Pre-heating also requires some extra alcohol, but IMHO, 10-20 grams of additional weight per cooking session is a small price to pay for a nicely working winter cooker.

The pre-heater makes it very easy to light up the Mini Trangia in freezing temperature (it has been pretty warm lately, and I have been able to test the pre-heater in only -12.5 degrees, but I’ll update this page as soon as it gets cold). (Update: Test at -25 C, test at -32 C, Snow melting test ). Pre-heating also significantly reduces the cooking time; bringing 500 ml of +4 C water to boil in 0 to 10 C outdoors temperature usually takes anywhere between 11 to 16 minutes, depending whether the lid has been on, strength of the wind, and such. By using the home made pre-heater with some 15-20 ml of extra fuel, the boiling time can be reduced to less than 8 minutes in twelve degrees below freezing. In my opinion, that is pretty good performance for an unpressurized alcohol stove. And finally, a word of warning; when using the pre-heater, the flames can be rather high (30-40 cm), therefore, the pre-heating should not be used near any flammable objects.

More info about camping stoves:
Zen Backpacking Stoves