Wednesday, June 25, 2008

Occasional Definitions: Zip Stove

(1) A sort of wood-burning stove made of discarded metal zippers. Can be zipped together for cooking, and then quickly unzipped again for breakdown and storage. When broken down, it resembles a pile of useless zippers, and can safely pass even the most rigorous customs inspection, though it can take hours or even days to reassemble if you lose the instructions, which will likely spoil your lunch and make you cranky.

(2) A sort of wood-burning stove made of sheet metal. Now called the "Sierra" stove. Has a battery-powered electric fan built into its base so it can operate like a tiny blast furnace. No, really. Has a battery-powered electric fan built into its base? What the fork? Actually works pretty well, but it's big and bulky. Some clever individuals have made their own from empty coffee cans and computer fans. A no-moving-parts, no-battery-required wood gas stove works just as well, and is simpler, cheaper and lighter. So there.
From: Fire In Your Hand

Wednesday, June 18, 2008

Gassify Me

What this is about: A batch-loaded, inverted down-draft gassifier (wood gas stove)

Name of stove: Inverted downdraft wood gas.

Type of stove: A wood-burner that works with one charge of fuel at a time to produce a hot, smokeless fire.

URL of original instructions: N/A. Rick "Risk" Allnut has done a lot of work (www.imrisk.com/woodgas/ddstove.htm), as has Ray Garlington (www.garlington.biz/Ray/WoodGasStove/). (For general info on light weight do-it-yourself stoves, see the Zenstoves links page at zenstoves.net/LinksGeneral-DIY.htm Also check out the Sierra stove at www.zzstove.com/).

Description of difficulty: Requires drilling a lot of holes, cutting and positioning springy and prickly hardware cloth, reaching into a sharp-edged small can to place bolts. Not too hard. Not harder than the DOSIP semi-pressurized alcohol stove, but if you have large hands you'll need to start with a bigger can. Overall, this is no harder than anything else here, but is larger and involves working with steel rather than aluminum. You'll need some "real" tools.

Disclaimer: This is for adults. It describes some things adults might or might not do with fuel, flames, tools, and sharp pieces of metal. Anyone working with fuel, flames, tools, and sharp pieces of metal assumes full responsibility for their own actions. Anyone attempting any activities or projects mentioned here is assumed to be intelligent, creative, responsible, and prudent. If you are not an adult, and are not also intelligent, creative, responsible and prudent, then do not act on anything you read here. The author is not responsible for anything you might do. You are.

Overview: This is about the simplest wood-burning stove that's worth building. There is a whole subculture of stove makers who have followed ZZ Manufacturing's lead and have produced wood-burning stoves with battery-powered fans, to match the "Sierra" commercial stove. All of these home-made stoves are clever, and some of them are elegant and well-finished. Then again, they are all dependent on battery power and electrical circuits.

A big step down from a stove with an electric fan is a can with some holes punched into it. This will do, but it is crude and smoky.

The wood gas stove falls in between, but not exactly in the middle. This stove is extremely simple, much more so than a can with a battery and computer fan, but yet it is also extremely sophisticated, and still has absolutely no moving parts whatsoever.

The operating principle of the wood gas stove is that burning wood produces smoke, and it is also actually not the wood but the smoke that burns. It is also the smoke that makes a stove smoky (Duh!), so the trick is to generate lots of smoke and then burn it before it gets into your eyes.

Commercial wood gas stoves use fans and flaps and doors and whatnot to control the flow of air and smoke, but our stove is just a cylinder in which you burn wood. That's a big plus. The fuel supply (if you have dry wood) is infinite, so you don't need to carry any. The stove is dead simple. Once you get it built, that's it -- nothing to adjust or maintain.

This stove also operates a little differently. Take the name: "inverted downdraft." Well, that's an updraft, an "inverted downdraft" is. Commercial wood gas stoves pull air in from the top and force it down from top to bottom using fans. This air flow is a downdraft. Our stove lets air flow from bottom to top, which is either an inverted downdraft or an updraft, depending on how fancy you want to sound.

OK, aside from being really simple in principle, the inverted downdraft wood gas stove is a little harder to make than most of the alcohol stoves here, even the fancier ones. You need an electric drill and a punch, and you have to assemble some parts using bolts and nuts and so on, so it's a bigger deal to make it. But once it's done, it's done.

It is also larger and heavier, and although you don't have to carry fuel, you do have to scrounge fuel on the trail, and you're dependent on finding suitable, dry fuel as you travel.

To use this stove, fill it about half full of fine, dry twigs, no larger than the thickness of a pencil. Even that is a little thick. Ideally, the pieces should be about an inch long and about a quarter inch thick, but it can be hard to break twigs that short, especially so as they get thicker. Finer is generally better, but also harder to find.

Once the stove is loaded with fuel, sprinkle a bit of stove oil or alcohol onto the top of the wood -- maybe a teaspoonful -- as a primer. This should soak in a bit, and supposedly stove oil works better, but alcohol works fine. Light it at the top, and the wood burns from the top down.

The heat of the flames at the top vaporizes the wood below the flame, and the open bottom of the stove allows fresh air to rush in and create a strong updraft. Additional air holes near the top of the stove mix in more air. All these vents, combined with keeping the cooking pot two inches or more above the top of the stove allows complete combustion.

Fuel should be loaded in horizontal layers. Oddly, having the fuel densely layered in is better than having it loose. Dropping in twigs vertically or letting them all jumble together does not work as well. Short pieces of fuel all laid down flat in layers works best.

When loaded, lit and used properly, this stove will burn almost without smoke. You will get an occasional wisp or two, but that should be about it. This is totally unlike the average wood fire or can stove, which has to be constantly tended, and which smokes before it gets going, while it's burning, and after it burns down again.

The wood gas stove burns cleanly, and quiets down from a roaring blowtorch to a cool smolder once all the volatile gases have burned off. At the end you get a clean, warm charcoal glow, which eventually burns out, leaving a little clean ash behind.

If you don't get enough fuel into the stove to complete your cooking, let it burn out and then recharge with fresh fuel, prime it again, light it, and start over with the new charge of fuel. Adding more fuel while the stove is burning will produce lots of smoke. Maybe that's OK from time to time, but don't be surprised by it. If this stove does not produce enough heat for you, build one using a larger can that holds more fuel. Scale up the measurements accordingly.

Technical details:

Warning: The stove described here is made using just about the smallest possible can. Larger stoves may be easier to make but will also be heavier and bulkier. You can twiddle to your heart's content. If you are a normal-sized man with normal-sized hands then you probably need to use a larger can, or check a different set of plans to see how other people did it. To make this stove you have to reach one hand inside the can to get a nut threaded onto a bolt, and the can recommended here is less than three inches in diameter. If you can manage this with tools instead of your hand, OK, otherwise you'll need a bigger can.
  • Height (can only): 4.4" (112 mm).
  • Diameter (can only): 2.9" (74 mm).
  • Full dimensions (including top and bottom supports): Height: 6.6" (168 mm); Diameter: 2.9" (74 mm).
  • Weight: 3.8 ounces (108 g).
  • Volume: Doesn't hold liquid fuel, but about an 8-ounce (237 ml) equivalent, when filled with broken twigs.
  • Composition: Steel. Steel can (Del Monte sliced peaches in the 15.25 ounce size), galvanized hardware cloth top and bottom (to serve as integral legs and pot stand), plus a few bolts, nuts and washers.
  • Cost: Free, if you have the materials. Requires some 1/2" hardware cloth, some bolts, washers, and nuts.
Materials list:
  • One empty 15.25 ounce (451 ml) Del Monte sliced peaches can or equivalent.
  • Marking pen
  • Galvanized 1/2" hardware cloth (a piece 4" by 24" (102 by 610 mm ought to be enough)
  • Ruler
  • Sandpaper (100 grit, or thereabouts)
  • Electric or manual drill, with 1/16" (or 3/32"), and 1/4" bits
  • Paper hole punch
  • Sheet of paper
  • Tape
  • Wire cutters
  • Screwdriver
  • Pliers
  • Work gloves
  • Wire
  • #6-32 x 1/2" slot-head machine screws (or equivalent)
  • #10-24 x 5/16" Tee Nuts (or equivalent flat washers)
  • Lock washers
Overview of construction process: Drill some holes in the bottom and sides of the can, then bolt a collar of hardware cloth to both the top and bottom.

Step-by-step construction:

1 - Start.

Open the can. Eat the contents. Remove the top of the can, the label, and wash the can. Sand down any sharp edges inside the top of the can.

Now try to stick your hand inside the can. If you can't, then you need a bigger can. This is OK. A bigger can is both taller and wider. Wider means more stable. It also means that the stove will be able to hold more fuel, making it easier to cook for two or more people. Look for a can about twice as tall as it is wide (think "smokestack").

2 - Drill ventilation holes in the bottom.

You will end up with two sets of holes, one in the bottom of the can, and one in the side of the can. We start with the bottom of the can.

Lay a ruler across the bottom of the can. Try to find the widest point, which means your ruler will be bisecting the can's bottom. Mark the halfway point. Repeat this two or three times and you should have a set of points that pretty well overlap, and indicate the center of the can. Put a big dot there.

Mark two more spots between the first dot and the outside edge of the can's bottom at approximately 0.5" (13 mm) intervals. This won't quite work out evenly, but think of it as a good chance to exercise your intelligence and judgment.

Repeat this on the opposite side of the central dot, and then at 90 degrees, so you have a cross pattern. Then make some more marks in an X pattern. Altogether, if you use this size can, you'll have about 33 dots.

Drill these out, first making a pilot hole with a small bit, and then with the large bit. It might help to take a nail or something else you can use as a punch and first make a small dent in the can's bottom at each dot before drilling each hole. Place the punch, give it a light tap, then drill the pilot hole.

Then use a small bit and drill a line of holes just inside the can bottom's outer edge. Check the accompanying photograph.

When you're done, you'll have the bottom of the can chock full-o-holes. This will form a fire grate.

3 - Drill ventilation holes in the side of the can.

Now for some fresh air vents near the top of the can.

Make a ventilation template by taking a full-sized sheet of paper (8.5" by 11") and cutting off a strip along the long edge. It should be 1.5" (38 mm) to 2" (50 mm) wide.

Take this strip of paper and wrap it around the can, overlapping the ends. Mark the point where the paper overlaps itself, remove the paper from the can, and cut off the short end.

Measure down from the top rim of the can about 1.4" (36 mm) and see where you are. The side of the peach can is corrugated. You want to be in the trough (low point) of one of these corrugations. Find the nearest trough and record that distance. It might be 1.4" or 1.5" or 1.55" or 1.6", but it shouldn't be less than 1.4". Let's assume that it is exactly 1.4".

Take your actual measurement and mark your strip of paper with it. You want to get a line running the length of this paper strip, and 1.4" (36 mm) in from the factory edge, but use your actual measurement. Then fold the paper in half four times and crease it hard. Unfold it and punch a hole at each point where the line you drew intersects with a crease. You will have 15 holes.

Wrap the paper strip around the can again, with one side of it snug up with the top of the can, and tape it in place. Arrange it so that none of the holes or the taped ends fall over the seam in the side of the can.

Mark the can at the center of each hole you punched in the paper strip, and put a sixteenth mark at the point where the two ends of the paper strip meet, in line with the other marks.

Now drill a small hole at each mark, then go back and drill them out to full size with a larger bit.

Now you'll have the bottom of the can full of holes, and you'll have another 16 holes in the side of the can roughly 1.4" (36 mm) from the top edge of the can, and the can will have no top. Sand off any sharp edges.

4 - Drill holes for the pot support.

Take a strip of paper as before and wrap it around the can, then cut it to length. It should be 0.6" (16 mm) wide. It will turn out to be just about exactly nine inches (229 mm) long. "Just about exactly" is close enough for us.

Measure in three inches (76 mm) from one end and draw a line across the strip. Repeat from the other end. Now you'll have a strip 0.6" wide by nine inches long (16 by 229 mm), with two marks dividing it into thirds.

Wrap this strip of paper around the top of the can. Arrange it so that none of the marks or the taped ends fall over the seam in the side of the can. Then use a small drill to bore a hole at each mark.

This hole may be big enough, depending on the size of your drill bit and the size of the machine screws you're using. But you can drill them out a little larger if you like. And in fact this might be better because it gives you a little fudge factor for positioning. Bottom line, as they say, you can always make the hole bigger later on, but no matter how often you drill it, it will never get smaller.

Just so you have three holes equally spaced around the can, and about 0.6" (16 mm) down from the top edge of the can.

5 - Drill holes for the stove base.

Do the same as in the last step, but use a strip of paper 0.5" (13 mm) wide. Wrap this around the bottom of the can. Arrange the paper strip so that none of the marks or the taped ends fall over the seam in the side of the can and drill your holes.

OK, now you have a can with three evenly-spaced holes in its side, near the top, and another three near the bottom.

6 - Cut and attach stove base.

Warning: To do this part, you'll have to stick your hand inside the can in order to get a lock washer and nut attached to the three machine screws that hold the stove base in place. If the can described here is too narrow for your hand, then you'll need to use a larger can. Or figure out another way to do this. Also, make sure you've dulled any of the can's sharp edges, or you WILL get cut.

The pot support and stove base are both made from half-inch hardware cloth.

Hardware cloth, if you're not familiar with it, is sort of like cheesecloth, but with a looser weave, and made from steel wire instead of cotton. And then it's galvanized (coated with zinc) to keep it from rusting.

For the stove base and pot support, you want to cut hardware cloth, gently bend it into a cylinder, and then bolt it to the stove. And look out for the edges. There is a sharp nubbin of wire every half inch, and they all bite.

Put on your work gloves to protect your hands. Using your wire cutter, cut a piece of hardware cloth 1.5" by 10.5" (38 by 267 mm). Using your wire cutter again, trim back any stray pieces of wire as much as you can. Sand down any nubbins that are still too sharp.

Bend the strip of hardware cloth into a loose cylinder to match the shape of the can. There should be one square of overlap at the ends (1/2 inch) when you wrap this around the can.

Slide a machine screw through one of the flat washers. (Note: I used Tee nuts, flattened their teeth with a pliers, and used a hacksaw to cut their necks off, to make them flat enough to fit. I did this because I couldn't find any flat washers that were both big enough in diameter and as light as these). Use what you can find -- you just need some fairly light washer that's big enough in diameter to cover the 1/2" by 1/2" hole in the hardware cloth.

Squeeze the hardware cloth together with one hand and fit it over the bottom end of the can. A heavy rubber band might be helpful to hold this together. With the other hand, slide the machine screw with the washer attached through the topmost square in the hardware cloth where the two ends overlap, and then through the hole in the top of the can.

Reach inside the can and slip a lock washer over the machine screw, and then thread on a nut. Hold the nut in place first with your fingertips, and then with a pliers and tighten the screw with a screwdriver, but don't cinch it down yet. Just get it snug.

Place the other two machine screws, make sure that everything is in place and level, then tighten down all three screws to the max.

Now one "rung" of the hardware cloth should be resting on the bottom edge of each machine screw, and the flat washers on the outside will be holding the hardware cloth tight against the side of the can.

Go back to the place where the two ends of the hardware cloth overlap and add a piece or two of wire as needed to hold those two ends tightly together. Twist the wire it into place using a pliers, then clip off the excess and tuck it in so it won't snag on anything or cut you.

When you're done, you'll have the bottom of the can sitting 1/2 inch (13 mm) off the ground, held up by the cylinder of hardware cloth firmly attached to the can. This will provide enough room for air to flow in and up through the stove. There will be one "rung" of hardware cloth up against the BOTTOM of the machine screws.

7 - Cut and attach pot support.

Put on your work gloves to protect your hands. Using your wire cutter, cut a piece of hardware cloth 2.5" by 10.5" (64 by 267 mm). Using your wire cutter again, trim back stray pieces of wire and sand down any nubbins that are still too sharp.

Repeat the process you used to make the pot support.

The pot support will have its weight bearing down on the TOP of the screws that hold it, while the stove base will have its weight bearing up on the BOTTOM of the screws there. This probably doesn't matter too much since the screws and washers are going to be squeezing everything pretty tightly together, and the whole shebang isn't really that heavy. You'll see how it works as you put it together. Now you know.

OK, done. The parts won't all be exactly square with each other, but they should be close enough so you can't tell from a foot away. The stove should stand straight and not be obviously leaning.

One advantage of the hardware cloth is that it has all those little sharp, pointy nubbins. These are like sharp little teeth, and while you have to be careful not to cut yourself or snag clothing on these, they also help to hold your pot in place, and on the bottom side they will grip too (even though you want to use this stove on a fireproof sheet of metal, just to be safe).

8 - Burning in and testing.

The stove needs to be fired before using it to cook with.

The hardware cloth you've used is galvanized, and the inside of the can may be as well, depending on what product it was used for. Both these parts need to be seriously scorched before you use the stove to cook with, because zinc is the galvanizing stuff, and fumes from zinc are toxic. You don't want to breathe these fumes or get them into your food.

Choose a safe, fireproof area such as a fire grate at a local park and charge the stove with dry twigs until it is about half full (don't overfill, less fuel is better, leave the side vents uncovered). Then light the stove and let it burn out. This will take around 20 minutes, because once the wood burns down you'll be left with charcoal, which will slowly burn down without smoke. You will be surprised at how long this takes.

Repeat this a couple of times. You should see very little wood smoke, and after the first burn, you should notice no smoke from the galvanized metal parts, or smell anything odd. The zinc smoke is very acrid. Don't breathe it. Keep a pot of water nearby in case you need to quench any flames, or the stove gets knocked over while it's burning.

As always, watch for problems, take your time. Relax, and keep it fun. Try boiling a pot of water. Yowsa! This stove puts out a huge amount of heat compared to the alcohol ones, and it burns just about forever, relatively speaking.

9 - Using.

Plan on using a pot lifter. You'll want to take your pot off the stove before the fuel burns out, and you won't be able to grab it with your bare hands, or gloved hands either. You do not want to introduce the sleeves of your clothing to the roaring flame that this stove produces. Using a pot gripper will allow you to manage the handling of your pot(s), and you may be able to both heat water for a meal, and then put on some more water for a hot drink without burning a second batch of fuel.

If you try putting on a pot of water and just letting the stove burn out, you may just boil away all your water, so plan ahead. You can buy a separate pot gripper or lifter at outdoor shops, or you can get a small pliers to take along. Maybe your pot has a bail handle that will let you use a tent stake or a long stick. Whatever works for you.

To use this stove, put down a sheet of aluminum foil (either from a roll or cut out of an oven liner) charge with fuel, set the stove on the foil, and light it.

The fuel for this stove is twigs. Finer twigs are better -- they should be no thicker than a pencil, and should be broken into one inch (25 mm) pieces if possible. Unless you find extremely thin twigs you will not be able to break them this short, but shorter is better. Do your best. Experiment.

Once the stove is charged, sprinkle a bit of flammable oil or alcohol on top of the fuel. Use about one teaspoonful and let it soak in briefly. Do not under any circumstances use gasoline, turpentine, thinner, acetone, or anything else explosive. Lamp oil is said to be best, kerosene is not explosive and should work. I've used only alcohol, which evaporates, or soaks in a little too fast, but it does work, and I always have it around for my alcohol stoves. You may be able to use some light paper, or fine, wispy, dry inner bark, if you can find this. But you will have to experiment.

Once lightly primed with a flammable liquid, light the fuel at the top.

The fuel will take half a minute or so to get fully lit. Before long you'll have a flame that looks a lot like it's coming out of a jet engine with the afterburner turned up to 11, and there will be almost no smoke.

Three things are critical: good ventilation through the bottom of the stove, where most of the air enters, ventilation from the holes around the side of the stove, which inject extra air into the smoke and flame, and the height of the pot support.

The height of the pot support is critical. The pot should be two inches (50 mm) or more from the top of the stove. The stove we've just made here has a space that is a little less than that, but it works well enough most of the time. Decreasing the free space between the top of the stove and the pot results in a stove that smokes badly, so if you have problems with smoke, chances are that the ventilation through the bottom isn't good enough, the vents in the side of the stove aren't good enough, or the pot support is too short. In the last case, make a taller pot support and retrofit it. You may also have fuel problems, but fuel varies from use to use, so it's hard to make a strict, foolproof rule.

Note: The vents in the side of the stove are also critical, and should be able to breathe freely, and should not be drilled higher in the stove. A little lower down is OK, but too high up is not. You need to inject fresh air into the smoke to help it burn, and that's what these side vents do.

The can used for these plans is very small and narrow. Because of that it's also relatively unstable. It's one of those ultralight tradeoffs. Using a wider can for your stove will give you a more stable stove, and your stove can also be taller overall while retaining stability. This is one of your personal choices, which is what the ultralight idea is all about anyway. Feel free to experiment.

This set of instructions is from my books. I have a big book with lots of stories and things, as well as a section on making stoves ("Fire In Your Hand"), and an excerpt of that containing just the stove making instructions ("Make Your Fire").

Fire In Your Hand (at Amazon)

Fire In Your Hand (at Lulu.com)

Make Your Fire: Make your own stoves (at Lulu.com)

Thursday, June 12, 2008

Perfect Pack Pockets.

Pouches, hidey-holes, tuckaways, pockets.

You find them all over, on all continents. Pocket gophers, kangaroos, hamsters and more all have some place to keep their valuables. Backpackers need them too.

Take a look at some climbing packs. Smooth, slim, sleek and clean. No external pockets. If there is any external cargo space it's usually a closed container, not something open ended as you'd find on a hiking pack. Climbers have their reasons.

First, they don't want things falling out. Things that climbers bring along tend to be high-value and irreplaceable, like the pieces of expensive, specialized equipment they need. Even if it's "only" food, climbers can't afford to lose it. They go to dangerous places in dangerous ways at dangerous times and need to guard against loss. Of food, of tools, of life. So they like slim, tight, sleek packs that let them move freely and do not catch on rock and do not spill.

OK for them. Backpackers are different. Not hikers but backpackers. If we can use the term "hiker" to mean the same as "day hiker" then we can cut to the chase and say that hikers don't count. Not that hiking or day hiking isn't good enough but that if you are out for a day (which is most of my hiking as well as yours) you (and I) don't have to be all that fussy. After all a day hike is a hike during the day, a few hours only and pretty much any pack that holds together will do.

So we'll let day our day hiker selves stand aside for the moment and watch.

Now let's talk about backpacking needs. Backpackers need pockets. A backpacker is someone who is out on the trail for days on end, maybe weeks, maybe months. I didn't make it to the big time. My longest trip was two weeks, but solo and unsupported (no resupply) as it was, there were plenty of issues to deal with.

Pockets help a lot.

The right pockets can make a huge difference. The right number of pockets, of the right size and shape, configured the right way, in the right places, with the right closures. In a way backpacking is all about pockets.

If you have a shop in the garage you know all about hanging your tools within careful outlines on pegboard and keeping all your screws and nails and washers in little labeled drawers. If you cook you do the same, but without the screws and washers and nails. You have spice racks and shelves and knives and pans, and spoons and forks, each in its own place, close to hand.

Pockets on a pack provide a major convenience factor. Efficiency doesn't matter much if you're walking five miles a day and can bail out at any time. It does matter if you're walking 20 or 25 miles a day and might be 10 or 20 miles from the nearest road. Pockets help you load up in the morning. They keep everything important handy all day, and they help you unload at night.

When you use pockets the right way you are organized. Pockets are organizers.

When I stop on the trail for either a short rest or for lunch I want at hand all those things I'll need but no more. Pockets do that. There is no need to rip open my pack and make it vomit its contents across the landscape. If I have the right pockets.

When I need to tank up on water at the end of the day I want to pull out my water bladders, fill them, drop them back into my pockets, and walk. When I need a wind shirt or an aspirin during the day I want it right there, right now. Pockets do that.

I've even been thinking for a couple of years about how I'd design a pack that was all pockets. No big bag to stuff full, just separate pockets, all out in the open, easily accessible, organized. Might not be possible but it may be worth another season's thought. Something to do. Thinking about gear design gives me something to do while I hike.

Pockets have two fabric types, mesh and solid.

Mesh pockets let you see what's inside them. Some say they stuff in wet gear and let it dry while they hike. If you can do this, please come and show me how, because I've never seen a folded wet wad dry out, but that's what they say. Anyway, a wet wad is better in a mesh pocket than inside the pack. Mesh pockets also snag if you aren't careful, and can tear easily. Really strong mesh makes a sturdy pocket but is heavier than solid fabric (surprising but true). Solid fabric is extremely strong and also smooth and slippery.

With mesh you also have the possibility of a small item tearing its way out through the mesh and disappearing behind you.

But solid fabric is opaque and leaves you groping blindly inside a pocket for the one item you need. I always try to put the same things in the same place every day but almost always end up swearing at myself for getting it wrong. I'm like that. A lot like that. You are probably a lot smarter. I want to be like you when I grow up. Send help.

Pockets are attached in different ways.

Most are sewn to the pack bag. This is good. It's a solid, secure and firm way of keeping the pack and the pocket together. And wouldn't you guess, it has a downside too. If the bottom of the pocket is sewn flat against the pack (even if it's pleated) you have a lot less room there. The pocket's volume shrinks from the top down like a funnel, and this makes the pocket less useful. But if the pocket has a cleverly designed box shape at the bottom then you have a big floppy pocket that sticks out and wobbles around and is more likely to get into trouble.

Some pockets are built into hip belts or attach to them. I don't have any experience with them really. Some hikers like them for cameras and small things. They add a lot of weight and probably add a lot of expense to packs because they're complex little buggers. The removable pockets are fine until you discover that one decided to stay in camp when you left.

They are small too, and if I want a small pocket for maps or pills or sunscreen it's easy to whip one out with a sewing machine and tack on a bit of velcro. Weight: about a quarter ounce.

I prefer to carry my camera in a small case on a webbing strap hung around my neck. Keeps the awkward weight off the hip belt, is handy to carry around without the pack, and I can still lose it whenever I want.

The last category of pocket attachments is the buckle-on or strap on pocket. These have been around for a long time. You generally find them in a bin at the outdoor shop. They are usually of fabric heavy enough to stop small arms fire, and a couple of them may weigh more than a whole ultralight pack. I think I have three, bought when I was lugging around a medium format camera and needed places for rolls of film or a spot meter, or just a bottle of water carried far away from my $5000 of camera equipment (since sold off at a big loss, but before film became totally irrelevant).

The strap-on pocket is basically a good idea but you pretty well have to make your own. If not, then you get something heavy, clunky, and huge, but they do have the advantage that they can be added or removed in minutes. I'm working now on a personal pack project that will have several of these, but designed and made by me for a pack I design and make myself. Me, myself, and I. We usually work well together.

Coming right down to it, pocket closure is really the big item. Hard to believe, but what a pocket is made of or exactly how it attaches to the pack is less important than how the pocket closes up.

This sounds nuts but it's true.

Most pockets these days, the ones on lightweight and ultralight packs, are made of mesh, and they lie flat against the pack when empty. They also have an elastic band at the top. In the store this looks really cool, and it is really cool if you carry nothing in them. Or only smallish, light, and flat items. Like a featherweight wind shell, or a ziplock bag containing a couple of maps.

The elastic eventually ages and sags out, but it's easy to fix. The main problem with these pockets is that they have no room to carry anything. Like a two liter water bladder or a full rain suit, or a day's food (all three meals), and your fuel, and stove, and cook set. When you are doing serious backpacking you need some serious external storage, and these flat tight pockets don't do it.

Besides being too tight the elastic isn't secure. It's fine if you tuck in a cap and a pair of fleece gloves, but two liters of water weigh four pounds. The mesh strains. Severely. You worry. Toss in a few small items and you're never sure you'll still find them with you at the end of the day. Because there is no way to close this kind of pocket securely.

Zippers are pretty well out. You will find zippers on heavyweight packs but even heavy zippers can break or jam. A heavy zipper used with light fabric is not a good match, and light zippers are useless all around. You can't depend on zippers.

Instead of using elastic or zippers to close pockets you can use a drawstring, especially if you make your own pack. A drawstring is a secure and solid closure if used with a decent cord lock. You can pucker the pocket as much or as little as you want, and a drawstring never gets old and sags. It is a truly positive closure. The downsides are that you probably will have to make your own, and you will have to manually adjust it each and every time you deal with the pocket.

Another problem is that if you stuff the pocket until its eyeballs bug out it will still stick out and flop around.

Pockets that close with a flap at the top are basically in the same category as those with zippers. These pockets are really for small and light items, and are not secure. I made a crude little map/pill/sunscreen pocket about five years ago. It works fine. Besides the velcro attachment I also have a safety pin holding it in place, just in case.

But I carry it high, on a shoulder strap, and can always glance right down at it. Even if it fell off I'd probably see, and would be able to rescue it. Not so if it was a big pocket on the back somewhere, and the top flap secretly came open.

This sort of flap can close with a secure buckle of some kind, but then again there would be the same problem as at the bottom of the pocket, only doubled now. The flap flattens the pocket and reduces the volume, so a pocket made this way would lie flat against the pack at both its top and its bottom end, and hold much less.

The last way, the one I'm tending toward, is a regular sewn-in, pleated pocket of solid fabric with either a drawstring or elastic closure at the top, but with one other feature: a vertical tensioning strap attached at the pocket's top.

The strap attaches at the pocket's top edge giving an upward pull to the fabric, and then locks into a buckle anchored on the pack bag. When the pocket is stuffed full and overloaded you can cinch the strap tight and put tension on the fabric. This squeezes the whole pocket closer to the pack bag and makes it flatter, but the squeeze comes only after you've loaded the pocket, and you also have control over the tension.

This sort of strap also spreads the weight, and the stresses. The pocket's bottom normally holds most of the weight, with the pocket's side seams assisting. A strap adds support at top, and is anchored either at a point on the pack bag or at one of the pack's strong top seams, taking a lot of strain off the pocket's seams.

This sort of strap can release in a second but not until you say so. Again there are tradeoffs. Straps and buckles add weight and complexity. Straps are more likely to catch on brush or rocks. They are one more thing to fuss with. A really smart buckle can find some way to get itself lost, without your permission.

I'm really sorry to say this but I'm afraid there is no perfect answer.

Every time I come up with another great idea I see the same set of constraints. Either you make something dead simple, light, with no options or you make something customizable, flexible, adaptable, complex and heavy. And more expensive.

Probably the best approach is to have at least two packs, a simpler, lighter and less flexible one for short trips and a more complex and heavier but customizable one for longer trips, where weight isn't as big an issue but flexibility of configuration is.

Anyway, it's nice to have problems like these. They give me something to think about while I'm trudging away. My mind really needs the exercise.

References:

BackpackGearTest.
Gossamergear.
LuxuryLite Modular Frame Pack.
REI.
Six Moon Designs.
ULA Equipment.


Wednesday, June 4, 2008

Pick A Pile Of Perfect Packs

OK, this will be fun. Useless (maybe) but fun.

I'll cover what makes a good pack.

First let's define pack. I'm talking about backpacks only, not day packs, fanny packs, book bags or any of the rest. That narrows things down but is still too broad a category to be useful. Too bad for me. I'll have to live with it.

And within backpacks let's assume that the packs we're considering could be used for anything from a one-nighter to a week long trip. In my experience that isn't a problem. If you can use a given pack for a week long trip then you can use the same pack for up to two weeks, for a trip with no resupply. You will have to fudge but you can make it work.

So we're really talking about maybe 95 per cent of all backpacking.

Oddly enough (you might think) the main criterion is comfort. That seems like kind of a sissy approach but it's realistic. If you use an uncomfortable pack that means right off that you have a serious problem, and it isn't a comfort problem. Tough guys may think that they can take it. They can't. We're all bags of meat with a few odd bones added for fun. No one is tough. Being tough means only that you can fake it for a while. Faking it is not what we're after. If you have to fake it you're already a loser. Get lost already.

An uncomfortable pack is one that doesn't work. Period. This is not a matter of feeling sort of OK versus feeling almost sort of OK. That might be the case for an hour or two but multi-day trips don't work that way. Especially 10 to 14 day solo unsupported trips, when you are carrying everything you need and you are totally on your own.

In those conditions you have very little margin for error, and what bugs you in a minor way during a two hour day hike can become either a major annoyance or even a serious injury over the course of a two week trip.

What is comfort?

Comfort means that the pack fits your major dimensions. The pack bag should be long enough for your torso but not too long. Short enough but not too short. Etc.

Measure from the top of your hip bone (pelvic collar) to the base of your neck (the large vertebral knob where your neck meets your shoulders). That's the length.

The shoulder straps should be long enough, and adjustable. Same with the hip belt. Everything should fall into place. Try out the pack with a full load in it.

Maybe the pack does not feel right at first. Unfortunately only experience will tell you how your pack should feel. If you're missing that comfy feeling but you can adjust the pack into compliance then maybe that will work but maybe you should try another one, because you've just used up your fudge factor, and you may need that on the trail.

The shoulder straps should be wide enough but not too wide. This is a personal decision. They should be padded well enough (when in doubt, go for more). They should be long enough to accommodate you wearing all your clothes and then some, and you should be able to shorten them so far that they hurt while you're wearing only a T-shirt.

The straps should not feel comfortable around your neck because they shouldn't get close enough to your neck to make that an issue. They should conform to your rib cage where they make that twist down there, where they go from being flat against your shoulders to flat against your ribs.

Back to the bag. First you measure it against your torso size, then against the tasks you will assign it. If the bag is too long or too short for your body you will suffer, but it also has to be large enough to handle the loads you will be carrying. That pretty well translates into diameter. Diameter is variable. Smaller is generally better but it doesn't matter too much.

For lightweight backpacking many of these criteria will be less important than for heavy ("classic", "traditional", or "ordinary") backpacking. I've seen empty packs that weigh 10 pounds. Insane. That's an issue right there. With a light pack lightly loaded you have a lot more leeway because the pack will not be stressing any part of your body as much, and the load you carry will not be stressing the pack so much.

There is a large "but" here, and it's not me.

The but problem is that if you are out for seven to 14 days most of the weight you carry will be food and fuel. Mostly food. Depending on who you are and what you need, food weight will be one and a quarter to two pounds per day, and this begins adding up scary fast after about four day's worth.

For a 14 day trip you may have 10 pounds of gear and 28 pounds of food. That's still pretty light overall, but stuff it all into a frameless pack with a small comfort margin and you will experience hell for the first week. And your pack may fail if it's not up to the job. This is not good, especially if you are out alone and 20 miles from the nearest road.

Keep that in mind.

I also think that a hip belt is mandatory. Some packs have removable hip belts, but that sort of feature makes the pack heavier, more complex, and probably more expensive. You might be able to handle a pack that has a waist belt rather than a load-bearing hip belt. If so, I still recommend it.

Some kind of belt or strap around your midsection is priceless if you have to stabilize the pack. You can cinch that sucker down tight and not have to worry about your pack wobbling as you make some tricky maneuver. Personally I like real hip belts because they take almost all the weight off my shoulders, which get really cranky if they have to carry all the weight, or even a lot of it. If you are on your feet, walking, for eight or 10 or 12 hours, then a hip belt really does make a difference. If you decide you don't want one after all you can cut it off as a last resort, but it's ever so hard to add one later.
Added to all this, weight is important. Weight and durability go together. They don't have a one to one relationship but they play in the same sandbox. Greater weight, greater durability. Usually.

Unless you're dealing with one of the big manufacturers that believes any and every gimmick they can add is a good thing. Remember too that if you buy from a large company you're also buying a significant safety margin. Not for you but for them. They don't want their products to fail in any way because that's when they get sued, so they overbuild.

Small companies sell to savvy buyers, so they can significantly cut safety margins. Not eliminate them or sell crap, but find a practical balance point. Everyone wants a pack that will last forever but if you buy a six ounce pack and it lives through a couple of seasons of moderate use before wearing through somewhere, then you'll forgive it. You understand, or you wouldn't have bought it. You wouldn't even have known of it if you were clueless, so you cut the maker some slack. You know how to use real, light equipment wisely.

When we talk of a pack's durability we're usually thinking about its fabric. Most of the pack is made of fabric. Pay attention to that, and watch the seams. But don't forget that some significant parts aren't fabric. Eyeball the hardware -- all those buckles and cord locks and ladder locks -- all the plastic doodads that are essential for the pack to keep working.

Normally a pack's hardware will not be something you really need to think hard about. Most of it is pretty standard, but do take a look at it. Make sure you have what you will need and that it is in working order before you bet your life on the pack. Just because.

Some other important aspects of your pack are more subjective and require more experience to judge.

One of these is how easy the pack will be to load and unload. This isn't hugely important because normally you will load the pack once a day and unload it once a day, and both times you'll be in a pretty stable environment -- your camp. But it still matters.

One of my packs is a Moonbow Gearskin. I like it. A lot. But it can be a real booger to get loaded in the morning because unfolded, flat, for loading, it is only a piece of fabric. There is no place to stuff anything. Some days I feel like I need six hands to get my things into the pack and get on the road. This is especially true since I use a backpacking hammock and often camp on steep slopes. I keep laying things into (onto) the pack, in a pile, and then they slide off madly in all directions.

Use your imagination if you haven't done this. Lay out a piece of fabric, then pile all your gear and food onto half of it, and fold the other half the fabric over and cinch the two halves together. Now do this on a 45 degree slope.

Hard. Very hard. Damn near impossible some days.

That's one reason I've taken to designing and making my own packs. Another reason is that I don't normally need something as big as the Gearskin. The packs I design and make suit me because I build them based on what I've learned the hard way.

But I don't know what's right for you. Like everyone else, you have to learn what's right for you.

Besides loading and unloading you need to pay attention to another "soft" aspect of your proposed pack. That is how easy is it to get at things you need during the day, while you are hiking?

This is actually a pretty big deal. Not a life and death issue, but having the wrong pack can make your life annoying to you. I'm still working on this one.

The Gearskin can be good for access, if you cinch things in tightly and take a chance or two, because with its open sides you can reach inside from the top or either side and pull out what you need. If you need clothing, this is OK, but if you stuff a water or fuel bottle so it can be pulled out the side, then you have to be really careful, because it might sneak away when you aren't paying attention.

Here is where we start getting into minor issues.

External pockets. I'm a fan. Big time and hassle savers, but still not perfect. How many pockets, where they go, how deep they are, how they are closed off, and so on. No perfection. No right answer. But I like them.

Aside from pockets themselves there is the question of whether you want an extension collar at the top of the pack. Can be useful. Can be handy. Can lead you to take too much stuff and overload the pack just because there is a little extra room at the top of the pack. An open top, whether it has a drawstring closure or a roll top is also a potential entry point for water. Then again it is a potential exit point for your stuff, when you need to grab it fast.

Because of how I camp and how I travel I like a front loading pack. Sort of a cross between a Gearskin and a traditional front loader. No zipper though. I use a flap of fabric to close it off and then have compression straps to tighten the pack and keep things together. Because my packs are frameless compression turns the pack into one solid wad, and gives it rigidity. This lets me reach inside for some things. It works up to a point.

An expansion collar at the top tends to defeat rigidity by making the pack bag bigger and sloppier, but eliminating it severely limits the amount of stuff I can shove into the pack, and makes my gear harder to get at quickly, so it's another tradeoff.

Pockets help, but then again large pockets all over change the pack's balance, and filling a large pocket that's not tightly secured leaves it wobbly, a potential gear-loser.

One thing I do really like about the Gearskin and my own designs is the ability to reduce or expand the volume of the pack as needed, using compression. I'm still working on this in my own designs, but getting closer. The pack bag stays the same height all the time, and swells in diameter as I carry more, or shrinks during a trip as I use up food.

But because of compression straps running horizontally I can keep the pack cinched tightly together into a stiff cylinder that feels good against my back. I'm working on some ideas now to use an add-on supplemental pouch or two (maybe even one on front) to carry extra food, or to distribute weight. This would also help in carrying things like rain gear and extra clothing in cold or wet weather, but let me reduce the size and weight of the pack in the summer, by leaving the extra pouches home.

Color.

This is about the last thing to worry about. Some people like bright colors, some don't. I prefer dull colors of neutral density: medium gray, medium green, dull blue as a last choice. I almost always stealth camp and an inconspicuous pack helps. But this is totally a matter of personal preference, and maybe as good a reason as any to make your own gear, because you can use any color you can get your hands on.