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Outdoorsy stuff > DIY robust retro backpack stove

You’ve constructed your own DIY robust retro Coleman-derivative wilderness stove following the instructions on the Construction page. Now, closely follow these instructions to prepare and pack it at home, and (out in the wilderness) locate it, pressurize and assemble, light it and use it, and address issues that may arise.

Everything about operating this mini stove is identical to operating a big, green, suitcase-style, gas-fueled Coleman camp stove. The only additional steps here are hooking the rod to the tank and windscreen to the burner and placing the grill on the burner, Steps 12, 13, 14. If you can work a traditional gas Coleman stove or lantern, you can work your DIY stove, easily.

Home prep and packing
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1. Load the tank no more than ¾ full with Coleman
® Camp Fuel. (An air gap at the top is needed.) Use a funnel. (What’s Coleman Camp Fuel? Scroll down to the bottom of this page.)
2. Ensure that the tank cap is on tight and the big black flame-control knob is turned fully, firmly to the right.

“Righty tighty, lefty loosey”


Turning a knob to the right, like a car steering wheel, tightens/closes it. Like your yard faucet. This time-honored rule applies to three stove controls: tank cap, pump knob, and black flame-control knob.

3. Ensure that the pump works:

Test the pump. Follow Step 9, below. If you feel steady resistance and you know the pump was oiled recently, then skip down to Step 4. If not, then the pump needs to be oiled.

Pump Oiling: A Maintenance Task


Oil is needed for the pump to work. Consider this an endearing quirk of these stoves. Oil is needed for an airtight seal between the pump plunger, which is made of leather (yes!) or neoprene, and the surrounding pump chamber walls. Fastidious owners of a tank with a leather plunger may wish to use baseball-glove oil, in accordance with Coleman’s recommendations, rather than motor oil.

A good oiling is probably adequate pump preparation before an extended wilderness trek. However, the pump should be oiled after about a week of use or after the stove has sat unused for several months. The oil tends to vanish, either by leaking into fuel tank (harmless), by evaporation with stove heat, or simply over time.

  • Find the oil port on the tank next to the pump knob. This oil port is a small hole with the word OIL stamped next to it. (It is not the air hole on the pump knob itself.) Squirt motor oil liberally into the correct port and move the pump knob in and out and turn it left and right to distribute the oil. Retest the pump (Step 9).

  • Better yet, remove (temporarily) the pump base cap. Notice the plunger, coat it with motor oil, and drip more oil into the chamber above the plunger. Tilt the tank to let excess oil drip out. Twirl and move the plunger up and down to distribute the oil. Reassemble the pump. Retest it per Step 9, below.

  • After the pump successfully passes its test (Step 9), release any tank pressure to minimize the chance of fuel escaping in your pack: Carefully open the tank cap, and then screw it back on again tightly.


4. For packing, fold up the windscreen (steel version) or wrap the (aluminum) windscreen around the tank.
5. If desired, place the pot support inside a stiff container, as described in Construction.

Locating
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6. Set the stove components outdoors, on level ground that is free of combustible matter (tree needles, dry weeds, etc.) a distance of at least a few feet around, and where other combustibles such as tent fabrics are at least few feet away. A large, flat rock surface or gravel or sand would be satisfactory. Natural wind protection using rocks or trees might be useful, but heed the warning below.

Life-or-Death Warning !


Do not use any stove or flame in a tent or any other enclosed, restricted, or poorly ventilated space. The dangers are many:
• Stoves create carbon monoxide, an odorless, invisible gas that can kill you without warning. It kills 2,100 people per year on average in the U.S.
• Stove use consumes oxygen.
• Stove flames can light tent fabric, hair, and clothing on fire.
• Stray fuel vapor from a stove can accidentally escape, accumulate in an enclosed area, and explode.
• A stove’s liquid fuel can spill and be lit on fire by accident, or it can evaporate and then be lit and explode.

This stove and others like it will perform safely.
However, careful operation by competent persons, outdoors only, is critical.

Pressurizing and assembling
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7. Check the fuel level in the tank, and then replace the tank cap tightly. (Watch the 13-minute video.)
8. Ensure that the black plastic flame knob (see photo below) is turned all the way off, to the right.
9. Pressurize the tank using the pump:

  • Release the pump knob by dialing it to the left, and extend it from the tank as in the photo below.

  • Place your thumb firmly over the hole in the pump knob.

  • Give the pump about 30 full strokes.

  • If desired, reseat the pump knob by depressing it into the tank and dialing it to the right.


10. Insert the generator tube through the hole in the windscreen and into the opening above the burner.
11. Manage the windscreen so its slot accepts the tab on the fuel tank.
12. Insert the free end of the connector rod through the hole in the tab on the fuel tank.
13. Insert the bolt on the windscreen into the hole in the burner support triangle.
14. Place the pot support (grill) securely on the burner.
15. Position the stove so wind will flow around the outside of the windscreen.

Lighting and cooking
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16. Important! Flip the mode selector up. It’s the thin, short steel rod shown in the above photo. Watch the video.
17. Turn the black flame knob to the left about ¼ turn. A steady hissing sound should be heard.
18. Place a lit match or lighter to the burner head. A steady, mostly blue flame about 3 inches tall should result.
19. Confident users may now place cookware on the grill.
20. After the burner has successfully flamed for (important!) at least 1 minute, turn the mode selector down.
21. Adjust the flame as desired using the black flame-control knob: turn left for more flame, or turn right for less.
22. Give the pump a few more strokes to make up for the pressure loss when the stove ran initially in vapor mode. Review Step 9 for stroking the pump.
23. After every 10 to 20 minutes or so of stove use, give the pump several strokes to maintain pressure. If, when pumping, high resistance is felt and/or the flame does not increase, then the tank has adequate pressure.

Relighting


You may want to relight the stove at some point. If less than a minute has passed and the generator tube is still hot, then relight with the mode selector down. Or, if more than a minute has passed (generator has cooled), then turn the mode selector up, relight, and turn the mode selector down after at least 1 minute.

After-use actions

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24. Turn the black flame knob all the way to the right until it is firmly closed (off).
25. Wait for all flame to disappear, and allow all stove components to cool, which will take several minutes.
26. Disassemble: Perform Steps 10 through 14 in reverse order.

Issues
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Tall orange flames. When first lighting the stove properly, it’s OK to see minor orange flame spurts (mixed with blue) that last only a few seconds and look like they’re settling down. Play with the mode selector (up for at least a minute, then down) and black fuel knob (close or almost close for a while, then open) and see how it goes.

However, if the stove just spurts wild, foot-high orange flames that won’t settle down no matter what tuning you try, then you either neglected Step 16 (didn’t flip mode selector up before lighting) or Step 20 (didn’t wait at least 1 minute before turning mode selector down). I’ve done this a few times.

Panic ye not. Calmly, immediately, turn the black knob to the right, off. There is no danger of the stove itself exploding. Liquid fuel has spurted out the generator into the burner assembly, has puddled there hidden from view, and is giving improper flames at the burner head and interfering with proper stove function.

This situation is potentially dangerous in a few respects: do not spill fuel onto yourself, and do not light any spilled fuel. Do nothing for several minutes except watch the flames die out while ensuring they will not endanger persons, the environment, or possessions, in that order. Notice that nothing's been said about tossing stuff onto the stove to “put out” the flame; don’t.

Even after the flames have died out, a small puddle of liquid fuel will probably still be sitting hidden inside the burner. Drain it out by carefully disassembling the stove and delicately tipping any liquid fuel out of the burner onto an appropriate surface. Choose an area of noncombustible dirt or rock away from camp, far from where any flames will later be lit. Gloves or tools may be necessary. Use extreme caution, as hot, flammable, possibly still burning fuel will drip out and tall flames may result.

Then, after stove parts are cool enough to handle, reassemble the stove. Place a lit match or lighter to any visible moist fuel spots on the burner. Watch for flames, and let them die out. Now, resume operation as normal. Observe Steps 16 to 20 more carefully this time. Do not ignite liquid fuel on the ground where it was drained.

Weak or no flame. When the flame is much weaker than expected, a few basic steps should be checked.

  • Is the tank cap screwed on (to the right) tightly? It needs to be on tight to keep the tank pressurized.

  • Is there enough pressure in the tank? Try giving the pump about 20 strokes. Review Steps 3 and 9.

  • Is the black flame-control knob turned enough to the left (open)? Try that, and try relighting.

  • Is there fuel? Turn the stove off, detach the tank, and shake or open the tank to listen or look for fuel.

  • Is the windscreen diverting wind adequately? If not, reorient the stove or move it to a sheltered location.

  • Is the pump sealing in the tank pressure? Give the pump several strokes and watch if the flame increases and then drops over the next minute. If you've addressed all the above steps but the flame is still weak, then check for a clogged jet (below) or refer down to Pump won't pressurize ... .

  • Not a basic step, but rather a long shot: Is the jet clogged? The jet is the small brass nipple on the end of the generator tube. Poke clean its tiny hole using a single bristle from a toothbrush or a thin wire taken from an electrical cord. Hang onto your cleaner tightly and don’t lose it into the jet !


Pump won’t pressurize far from civilization. You neglected to adequately oil the pump before embarking on your wilderness trek (Step 3, above). Now the pump gives no resistance when you stroke it, fuel won’t flow to the burner, and you’re far from any supply of motor oil. But you are a resourceful do-it-yourselfer.

  • Try human saliva. It works. Raise just the tank (with tube, minus all other parts) to your mouth, and seal your lips around the pump base. Feel with your tongue for the oil port. Use your tongue to squirt your spit down the oil port. If your spit has magically left your mouth and hasn’t dribbled down your chin, then it’s gone down into the pump. Twirl and move the pump knob up and down. Review Step 9, above, to test.

  • Other alternatives (I’ve never tried these) could be cooking oil, margarine or butter (preferably melted and clarified), warmed-up Chapstick or other lip balm or grease, or detergent. Rather than use the above mouth-injection method with such concoctions (yuck, and likely ineffective), you’ll want to take off the pump base cap and apply your lubricant to the plunger and into the pump tube. Review Step 9, above, to test. Take care not to lose the small parts of the pump base cap.

  • You’ll likely achieve a pump plunger-to-wall air seal with one of these last-ditch efforts. But, your lubricant could do odd things to the pump valve inside the tank or to the fuel, deliver odd stove performance, and cause internal rusting. When back in civilization, a rinsing of tank and pump, preferably using Coleman Camp Fuel, will be in order.


Generator tube cleaning
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I’ve never needed to do a tube cleaning, but nonetheless I’ve done it simply out of fastidiousness. Carbon deposits can accumulate inside the generator tube, the slender one that sticks out from the tank. It unthreads from the controls on the tank, and the brass jet head unthreads from the tube. Scrape out the tube using some wire (coat hanger) or pipe cleaner, blast out using compressed air, and reassemble.

While you’re at it, clean the jet orifice (tiny hole in brass nipple) using a tiny wire or toothbrush bristle. Also clean out any spider nests inside the burner tubes. Yep, they love it. I’ve seen it. The stove, though, is called robust for a reason, and tube cleaning (very rare), nipple jet clearing (occasionally), and pump oiling (frequent) are all the maintenance it needs.

Coleman Camp Fuel
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The best fuel for this stove is Coleman Camp Fuel. It’s easy to find and packaged in gallon cans wherever camping supplies are sold: sport shops, mountain shops, and hardware, drug, and grocery stores. Per ounce it’s around an eighth the cost of cartridge fuel (butane and related mixtures).

Coleman fuel appears to be a light naphtha formulation, a petroleum distillate consisting of hydrocarbon molecules in a narrow range of five to nine carbon atoms per molecule; the middle of that range is seven carbons, or heptane. It’s chemically situated between butane, which has four carbon atoms, and gasoline, which has an average of eight carbon atoms per molecule (i.e., octane). Gasoline is a witch’s brew of petroleum distillate hydrocarbons with four to twelve carbon atoms per molecule, plus benzene (a nasty carcinogen), oxygenates (nasty for stove valves and seals), and who knows what else, good (like detergents) and bad.

Coleman Camp Fuel is thus a neat hybrid. It can be poured, contained, and generally handled like gasoline, as a liquid. Use a funnel though, and cap whatever container it’s in very tightly, especially when hot weather descends upon you. Handling Coleman Camp Fuel is common sense, not especially tricky, but not foolproof either. It vaporizes readily (less well than propane or butane but faster than kerosene) and thus performs nicely in appliances designed to run on it, as our DIY robust retro Coleman derivative most surely is. Coleman fuel’s exact formulation isn’t public knowledge, but suffice to say it’s a relatively pure, quality-controlled, dependable, inexpensive, widely available commercial product free of most oddball components in gasoline.

Can gasoline substitute? It’s definitely cheaper, some $3 to $4 per gallon versus $13 for Coleman fuel. And it does work, yes, although longer time in vapor mode, with selector tab up, may be needed. I’d use gasoline when in a pinch or “emergency.” But I wouldn’t load my stove with gasoline just to save a buck ($1) when a precious wilderness trek by me and companions lasting several days will depend on a stove’s operation. Stoves include delicate seals and narrow jets, and one can’t predict how long those seals will stay tight and jet orifices will stay open under the onslaught of additives and longer-chain hydrocarbons in commercial gasoline. Consider gasoline use a discouraged, DIY application you would attempt only at your own risk.

Disclaimer
Execute this project and use any resulting product solely at your own risk.

Disclaimer
This web page and the information therein have received no input, authorization, or endorsement from,
and the author has never had affiliation with, The Coleman Company Inc., or any other mentioned manufacturer.

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