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Long Permaflate on Ice

Not a skating spectacular, not a cool, in-depth article covering winter camping on New Hampshire lakes, but just a complete collection of all the material on the Long Permaflate.

I, personally, thanks to the suggestion of Roger Caffin, who said a short version would be a good idea, and why didn't I make one, have gone from wondering why anyone would ever need a short airbed, to wondering why they would ever need a long one. The short version is now so far ahead in lightness, handling, toughness and comfort that the whole long permaflate is, well, on ice.

If you, personally, are totally convinced that you must have a long airbed, I suppose I can wake up Sleeping Beauty, but until then, the rest of this section represents a vault of sorts, in which the long permaflate project will lie undisturbed.

If you find vaults unsettling, you are welcome to head back to Index

Vital Information

If you are thinking of buying a long permaflate, or have just bought one, you should be informed that most new buyers report the following as soon as they inflate their purchase.

1. I can't push the stoppers in hard enough. When I lie down on the airbed or move it around inflated, stoppers start popping out.

2. Now I have put the stoppers in properly, when I lie straight down the middle of the airbed on my back, the two centre tubes harden up under the pressure and feel most uncomfortable.

Answers

1. There is a 'knack' to putting in most airbed stoppers and the permaflate is no exception. If you were inserting a tight cork into a wine bottle, you would have no luck until you twisted the cork as you pushed it in. Twist the permaflate bung as you push it in, so you are 'screwing' it into the hole. If you want it easier still, moisten the bung. The bung should steadily insert as it is screwed in. Once you start to worry how you are ever going to get it out again (unscrew or lever side-to-side with the fingers) the bung is definitely in far enough, and will resist sleeping or sitting pressures for weeks if required.

2. Since the airbed is built of six individual tubes, if all the pressure is taken by the central pair, of course they harden up. Although uncomfortable, the position is useful for doing some sorting to a complaining back on a camping trip. All you have to do for normal use is lie with your head, say six inches to the left, and your feet six inches to the right. This slight angle allows other tubes to share the load. When you are lying on your side with knees bent more tubes are compressed so the problem does not arise. If you insist on lying straight down the bed on your back, soften the two centre tubes by letting some air out of them until the other tubes are also taking some of the load. NOTE: This is a characteristic of the long permaflate that cannot be 'fixed'. The different design of the newer short permaflates does not have this characteristic, but the bung insertion requirement is the same for both models.

Long or short permaflate?

When the development of the long permaflate finished, it was useful, robust and not too heavy. A good friend worked very hard at persuading me to build a lighter, shorter version, I finally gave in, although it looked most unlikely that I would ever use such a device. The short permaflate is more complicated and has been built with unlikely camping in mind. I must own up to using the short version exclusively now, which at least shows I have confronted my own prejudices.

Although I now camp 'short', and the short model is considerably dearer, I would hesitate to recommend it to many campers. If you camp on flat ground, avoid low temperatures under canvas and are not walking too far, get a long permaflate. It will work straight out of the packet (provided you have read 'Read me First'). The rough nylon sleeve stops you slithering around, but also picks up fluff from carpets, and dirt from the great outdoors. Over a few nights the tubes start to slip an inch or two out of the open ends of the sleeve and need pushing back, but apart from this the long permaflate forms a very good introduction to camping with this airbed. The weight is a reasonable 920 grams, and winterising with a sheet of closed cell foam or strips is possible. After getting used to the device, if you like it then give it to your best friend, buy the short version and begin modifying and adventuring.

If you are a camping expert, or consider yourself one (which is the same thing), you are welcome to wade through the sections on why the short permaflate takes its present form, and why after purchase you are likely to need some sewing adjustments before it starts working properly for you. The short permaflate has a six tube sleeve base normally made out of ultralight slippery nylon plus six tubes similar to the long version but using lighter gauge poly film. Sleeve lengths will be available to deal with tall and short campers, but the sewn overlay that goes on top alters to personally fit the one camper that will be using the airbed.

Long Permaflate inflation and assembly

Note: This is an older section that has been left in since it contains background material, and detail about possible but unlikely problems. Short permaflate inflation is covered in the 'Short permaflate' chapter, but the hints may apply to both models.

'Read me First' contains full details for stopper insertion. Reading it will make first-time inflation easier.

Remove the long permaflate from its pillow bag. Polythene tube ends with inflation holes should be visible at one end of the sheath, which we will call the top or head end.

If you ordered captive stoppers (or bungs, a different name for the same items) they should be visible on their nylon anchors close to the inflation holes. If you are using loose bungs, locate the bag that holds them.

In each of the three sewn divisions in the fabric sheath are two tubes. Make sure the three uppermost tubes all have their inflation holes facing you, turn the sheath over to look at the other three tubes and make sure their inflation holes are visible as well. If any inflation hole is facing inwards, pull the tube most of the way out of the sheath, flip it over so the hole faces outwards and slide it back. If you are doing this for the first time with a long permaflate, it pays to have enough floor space handy to lay the sheath out flat. If the tube will not go all the way back inside, you can reach in from the bottom end of the sheath and pull it, or pull its companion tube out a few inches then hold the two tubes in contact and push the pair in a few inches. Pull the companion tube out a few inches again, and repeat the process until the pulled-out tube is reinserted.

Since both sides of the sheath are the same, you can start on either set of three tubes. Pull the first tube out a couple of inches to get easy access to the hole and blow it up. Working with loose bungs is as easy as the anchored variety, as long as you always have a bung ready in your hand when you are blowing up a tube. Slip your finger over the hole when the tube is full, then slide the bung in to replace your finger. Inevitably there will be some air loss while this is done, but there is no need to make efforts to keep a rigid inflated tube. Do not yet follow the 'Read me First' instructions on proper bung insertion, as you may well need to alter the pressure. Once the bung is temporarily in, you can push the tube back into the sheath. then repeat the process for the other two tubes on the first side. Flip the sheath over and pull out the uninflated tube in the first division. When you have blown this up and stoppered it, you may well find you cannot push it back in. This is intentional. An over- inflated tube pair cannot be pushed down a sewn division. If the night is frosty, leave the tube to cool and get on with the others. The pressure will drop as it does so, and you may then find the inflated pair of tubes will slide in their sewn division. If conditions are normal room temperature, you will have to let a little air out of one or both of the inflated pair of tubes until they can be pushed in. In the long permaflate, where length makes the pushing harder, you may pull at the open bottom end if required. Repeat until the second three tubes have been inflated, adjusted if required and the pairs slid back. You may then follow the 'Read me First' instructions to screw the bungs in firmly. Since you cannot push in an underinflated tube, and an overinflated tube will not fit, all six tubes in the permaflate will be at nearly the same pressure.

The above detailed instructions read like a Marathon, but really do only contain the obvious.

Most airbeds lose air so fast that temperature effects are not noticed. The permaflate retains air for about three weeks, although there is a slight initial loss of oxygen by diffusion. If the evening is cold, within ten minutes the tubes will be much softer than when you inflated them. There is still normally plenty of air without reflation. What not to do is to blow up six tubes, then reflate the first tube you blew up because it is noticeably softer than the others. Of course it is since it has cooled down.

If you have a long permaflate with pillow bag, load clothing into the pillow bag and tie the end. The writer uses a twenty year old sleeveless padded nylon jerkin in the pillow, which is most comfortable. If you want to find loose spare bungs in the dark, leave them in the tied end of the pillow. The pillow has a slight 'wedge' shape, the tie end being larger when filled with clothes. This can be used to advantage to level the head when camped on a side-slope.

One horrible night you are going to find a flat tube. If you are too sleepy to care, put any odd clothing in a line on top of the airbed to fill up the groove that should not be there. This is surprisingly comfortable, and two grooves per airbed can be filled before the system gets out of hand. The centre sewn division, where all the weight goes, really needs two inflated tubes.

There are no tube replacement problems with the short permaflate. With the long model one method of tube replacement, which can be done without disturbing the other inflated tube in the sewn division, is to produce a short length of adhesive tape (insulation tape, duct tape) from nowhere. A sticking plaster will do. Stick the head of the replacement tube to the tail of the failure, and sleepily pull the failure out of the sheath. A painless source of insulation tape is to stick a length to a small poly bag. Before replacing the tube, check that the bung has not caused air loss by working loose by repeated contact with your head or the pillow. If the head end of the permaflate is in contact with the tent wall, your head and pillow will align far enough down the bed to avoid the bungs.

Without adhesive tape, pull out the failed tube, and working from the head end of the airbed insert the tail of the replacement into the sewn division, above the inflated tube, making sure the inflation hole faces upwards. Slide the inflated tube about a foot out of the head end. Hold the replacement tube to the inflated tube and push the inflated tube in again. Both will advance a foot into the sewn division. Slide the inflated tube a foot out once more, and repeat until the new tube has been inserted. Practice before it is needed, and you will find this can be done in minimal space in the tent, with a torch held between the teeth. Both you and the sleeping bag will have to be clear of the bed at the time.

Deflation - normal and winterised long permaflates

The short permaflate chapter again covers the short model, but read the following for handy hints.

Remove all six rubber bungs. The anchor lines on the captive bungs are made to resist moderate pulling, but if you try to remove forced-in bungs by pulling on the anchor line, the monofilament anchor knot will pop out of the top of the bung. You can reinsert it by a careful push with a very small screwdriver. The deflation process is best done inside an empty, or emptying tent, with the groundsheet providing a secure working surface. Pull down all six tubes in the sheath so the tube toe ends are at the very end of the sheath. Reach in to the toe ends, and smooth them out so they are lying flat in their original 'layflat' creases. The pair of tubes in each sewn division do not have to be one on top of the other, and will naturally lie side by side with some overlap.

Leave the whole airbed lying flat (no folding). Turn up the first inch or two of the toe, and roll the airbed not too tightly towards the head end. You will end up with a smooth roll the width of the airbed, with all the air in the bed removed. Now the air is out, unroll the bed until it is flat again. Flip one sewn division over so it lies on the centre sewn division, then flip the other edge sewn division on top.

For a normal or single insulation strip permaflate, roll up the three stacked sewn divisions. The resulting normal roll can be put in the pillow bag, but the single strip variant has a larger diameter, and you have some sewing to do if you want a pillow bag.

The winter permaflate cannot be rolled, since the three foam layers start to 'fight'. Fold the short head end in at the top of the three strip pile, and the long tail end at the bottom. The three strips can then be doubled over to protect the tubes.

The writer is a 'slow and deliberate' camper, like most solo operators. On the living-room floor the entire deflation operation described above (roll-deflate, unroll, flip-fold then roll again), took 100 seconds.

Rinsing out - all permaflate models

Any mouth-inflated airbed slowly fills with moisture, and the colder conditions are, the faster this happens. We have not yet seen a Thought Police campaign on the incredible risks of inflating other people's airbeds, but anything is possible. Not only does moisture build up, but after a year or so musty smells may appear as something or other starts growing in the friendly environment.

By holding the inflation hole of a permaflate tube to the cold tap, you can run in about half a litre of water, swill it round the inside, then roll the tube up to expel all but a teaspoonful. This takes about two minutes a tube, and clears out the nasties for another year. As far as we know, no other airbed design allows rinsing out.

Initial assembly

Persuading the set of tubes into an empty short permaflate sheath presents no difficulties at all since they just slide in. The following applies to long permaflates, particularly in confined spaces.

Do NOT place a rolled-up tube in the entrance of a sheath sewn division and blow hard. The resulting jerky, explosive progression down the sheath will severely damage the tube, and may actually hole it.

Slide your hand inside an empty sewn division until it appears at the other end. Take hold of two tube ends, one on the other, inflation holes upwards, and pull them back up the sheath while they unroll. Repeat for the other two pairs of tubes.

Your arm will not be long enough to insert as above on a winterized permaflate. Working from the end of the sheath that has no foam inserts, you should be able to push two rolled tubes about half way up the foam-insert section. Anchor the two inflation holes from outside with your other hand, while you take out the first hand, unrolling the tubes as you go. You can then reach in far enough from the head end to pull the pair of tubes up to the top.

If you don't like either method, a softly-inflated tube can be pushed straight up an empty sewn division, or one holding a deflated tube.

Winter permaflate camping

Before starting, a book recommendation for a series of slim volumes on camping written by Cliff Jacobson and published by ICS Books Inc in the USA. They will be referred to in the text as simply 'the Book' since they are that good. Winter camping is of course covered.

Airbeds are well-known as three season devices that are left behind when the snow falls. At minus 20 C the gentle cold reaching up from underneath starts to turn into a hungry monster. To go into a little more detail without stating the obvious, a sleeping bag expands a great deal when unpacked, and since thickness is the way insulation works, over the top of you where there is no pressure it keeps you warm. If you were tough enough to lie straight on the ground and sleep, the body points in contact compress the sleeping bag material beneath them, and cut the bag insulation dramatically. The result is a series of icy points on the contact areas. A closed-cell mat insulates better than an airbed, but you will notice when you try it you are still virtually sleeping on the ground as far as comfort is concerned. The closed cells do not compress overnight, so there is some good insulation, but underneath you the sleeping bag is still heavily compressed at the contact points, so the insulation is not as good as it might be. If you sleep on an airbed, some heat is lost since it is a poorer insulator, but the spreading of the body weight that makes it so comfortable also allows the sleeping bag to regain some of its thickness underneath you. An airbed is a little colder than a mat, but not a great deal.

To keep warm in winter we all have to carry more bedding. The immediate and very sensible response is to carry a closed cell mat and an airbed. The airbed stands on the closed cell mat and things are much warmer. If the airbed fails, you may not sleep, but you will not die. The writer did this for a number of years. The Book says the insulation is better if the mat is put on top of the airbed. One cold night this was tried after starting to feel the ground reaching up from underneath. It worked. The sleeping bag warmed up and it was back to sleep. A mat on top is much harder to keep neatly in place, but yes, it is warmer. Cheap closed-cell mats tend to compress at pressure points quite quickly, which levels out the bumps at the expense of keeping warm. The worst quality (chinese) mat we can find collapses immediately at the pressure points if you sit on it on the ground, but when used on top of an airbed the load spreading is such that it does not compress at any point, and functions as well as more expensive mats.

Practical long permaflate winterizing

To reduce the encumbrance of a full length mat, it is possible to shorten it so it starts at the shoulders and terminates below the hips. The pillow insulates the head, and since the legs weigh very little compared with the trunk, the sleeping bag beneath them is much less compressed, and they stay warm. Specific, and reversible modifications can be carried out to a standard permaflate nylon sheath to provide an insulating area that is incorporated into the airbed rather that flapping around on top.

You will need some 8 mm thickness EVA closed cell foam. Just buy an El Cheapo closed cell camping mat and cut the pieces from this. Three strips are needed 215 mm (8.5 inches) wide and 980 mm long. Insert (with difficulty) one strip into each of the three sheath partitions, and wiggle them until they fit neatly and flatly into the sewn divisions. With the tops of the three strips flush with the end of the sheath, pull them about 200 mm farther in, since head insulation is not needed.

All you need to do now for your winterized airbed is to load the tubes under the insulating strips and blow up the airbed. The strips curve as the airbed is blown up, and the result is what feels more like a mattress than an airbed, and insulates very well indeed.

If you deflate a winter permaflate, and then try to roll it up, you will have no success. A single flat fold with the lower half of the bed inside the fold is the most practical. Although the weight increase is only 100 grams, the size has greatly expanded. Ultralight camping is now compulsory, but fortunately not for the winter. I pull a sledge, myself, which deals with weight and bulk problems.

This winterized airbed is adequate for minus 20 C, which is as cold as the Australian Alps will go. The polythene used for the tubes is also specified for flexibility at this temperature. If you are using a permaflate in colder conditions than this, we would love to hear from you.

If you are confining yourself to moderately cold nights, say minus 10 C minimum, instead of inserting three closed cell strips into the sheath as above, much of the benefit can be gained by inserting just one strip into the centre partition of the sheath, since most heat transfer to the ground occurs from the centre area of the airbed. This variant can be rolled up, and thus remains reasonably compact and insulating as well. If you are going to tough it with a single airbed for summer and winter, this is the best compromise.

Assuming you are camped on snow in some shelter, with plenty of ventilation through your tent to sweep the moisture out a rough guide to minimum temperatures is as follows, assuming you have a one litre or so full plastic water bottle with a plastic screw cap, standing upright in the tent.

The cap freezes to the neck of the bottle, but the water is unfrozen.
Minimum minus 5 C

There is some, but not a lot of ice in the water.
Minimum minus 10 C

With the bottle standing on insulating clothes, and a shirt over it, some ice is still forming.
Minimum minus 15 C

With the bottle wrapped up in all your spare clothes, a small quantity of ice forms.
Minimum minus 20 C

Frugal Living

The Frugal Living newsgroup is an introduction to people who, from interest or necessity, are living on very little. The writer cannot read more than a few postings without thinking of how much he wastes.

A periodic question is "Can I use a camping airbed for everyday (or night) sleeping?".

The answer normally posted is certainly not. Even if you are lucky enough to find one that will stay up all night, within two or three weeks of use it will begin to leak, and the leak rate will accelerate. This answer exactly duplicates the writer's findings.

With the domestic 'testbed' permaflate approaching its first birthday, we could perhaps now substitute "possibly" for the above answer. The 'testbed' permaflate is not on sale, but Frugal Living exponents are adept at making things for themselves. The 'testbed' will be fully described below, along with the results and implications so far.

The permaflate tube length and diameter was chosen so ten side-by-side would fit a single bed. The sheath has the same 9.25 inch wide partitions as the normal one, but there are five partitions rather than three. At the time a light coated slippery nylon was being used for camping sheaths, so a heavier, rough polyester was used. The current rough nylon sheath material would no doubt be adequate. Small Velcro strip closures were sewn to one end of each of the five partitions at the 'head end' to stop the tubes over weeks of sleeping from working their way out backwards. The entire airbed was slid lengthways into a sleeve made by doubling over an army surplus heavy woollen blanket and sewing one end and the side. Much later a small closed cell camping mat was cut in half, and the pieces slid down the inside of the woollen sleeve so one was held above the foot end of the airbed, and one below. These pieces make the foot of the bed feel much more like a normal mattress, and the accelerated tube-end wear caused by pounding with the feet has stopped. Every few days the mat pieces start to move out of position, and are relocated as part of standard bed-making.

The bed base was an old, but not antique wooden slat type with nails, as usual, working their way out of the slats. These were hammered back in and a quarter inch thick sheet of hardboard (masonite etc) laid on top to make a flat base. Because of the tube separations, a permaflate is not a total vapour barrier, but air circulation through the base of the bed was judged not worth preserving. The tubes were inflated, the Velcro closures sealed over the bungs, and sleeping trials began. With the extra mass of the woollen blanket sleeve the bed 'makes' just like a normal one, with conventional sheets and blankets. A few tubes slowly failed at the base and were re-welded a little shorter, but otherwise it has been an uneventful year. Unless all the tubes explode tomorrow, the tester may never sleep on anything else.

On warm humid nights (there is an air conditioner for the real heat) the bed is noticeably damper than a conventional spring or open-cell foam mattress where the base can absorb moisture during the night, and release it during the day. On cold nights (Melbourne rarely freezes) an obvious chill came up from underneath, with only two thicknesses of the blanket sleeve for insulation. A piece of 8 mm closed cell foam was laid on the top half of the hardboard base, and the insulation was adequate. The bed is run fairly softly inflated, and the closed cell foam also makes sitting up in bed more comfortable. In climates where the room temperature drops below freezing overnight a thicker closed cell mat would be essential.

Almost all of the body pressure falls on the centre pair of tubes, which need a little more air about every three weeks. The next pair of tubes each side get air about every six weeks, and the two outer sets may be topped up after three to six months. Out in the bush inflated life is not as long, but when undisturbed except by sleeping a permaflate lives up to its name. At least another year of testing is needed before a positive recommendation is possible, but the permaflate may meet the needs of Frugal Living.

More time has passed, and it is possible to update the above research, and draw firmer conclusions. At least five tubes had been re-welded with an improved weld when the previous ends had been destroyed by foot pounding, and the closed cell sheets mounted over the bed end. Just over six months later they all failed over the space of a few days, as the result of a small stress fold at the foot of the tube. Such consistency indicates foot impact is no longer an issue. Some time later a minor stress leak opened near a valve at the head end, after over a year of use.

This indicates the life of the present tubes slept on every night is a little over six months. If you develop your own polythene welding repair technique, average tube life before the tube is not repairable will probably be between eighteen months and two years. At US $30 per six tubes, this is more comfortable than a cheap foam mattress, but not as economic.

Urban Camping

Urban camping, or squatting as it is less politely known, is the technique of camping out in unused and empty city accommodation. It has the advantage of being rent-free, and for that reason is illegal.

Since this is a nomadic life, normal camping requirements apply. Real living is being done, sleeping bags rapidly soil, and it is well worth doing the full 'boy scout' with washable inners, possibly using a thin jumbo sized sleeping bag with an inner blanket sleeve as well. In this application a six tube long permaflate acts like a normal airbed, apart from remaining inflated, and is recommended. The recently updated six month life means you will not be sleeping for nothing, but if rent is being avoided due to personal mobility, you should be financially ahead at an airbed cost of about US $5 per month.

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Photo Gallery - most of the short permaflate photos are in the dedicated section above.

.... Airbed and pillow (67 Kbytes)

.... Close-up of the tube ends and stopper system (66 Kbytes)

.... Rolled-up permaflates, normal and semi-winterized (81 Kbytes)

.... The full winterized permaflate (68 Kbytes)

.... Pack comparison of the normal and full winterized versions (103 Kbytes)

.... The pillow bag when travelling (72 Kbytes)

The full view is on file view.jpg (224 Kbytes) which is a JPEG file for viewing or filing for later use