DIY - My Designs

Send any questions or comments to the designer Roger Caffin

Home page


My Designs

I have spent a number of years trying to reduce the weight of my pack with lighter gear. This was difficult. Local manufacturers have to cater to the bulk market and make their gear strong enough that they are not inundated with returns from novices who don't know how to handle lightweight gear. They like to have a 'bomb-proof gear' reputation. Understandable. But with that strength comes weight, so what's on the market here is really too heavy. I started to research the market for lightweight materials, and found that our local gear is made largely with stuff from 30+ years ago: there are much lighter high-tech materials available now. So I started developing my own gear, and found I could significantly reduce the weight. You can see the results on the Ultra-lightweight page.

What to do with all this information? I am sure it might be of benefit to others (he hopes!). So I decided to document my designs and make them available through the FAQ site. If you want to reduce the weight of your pack, read on. But read the Disclaimer on the /FAQ/ page as well.



You didn't think you could just have designs without some discussion of my general design philosophy, did you? Fair go. A lot of it is actually written up on the Ultra-lightweight page, so I won't repeat (all of) it here. You will get my own biased opinions here rather than some attempt at an unbiased concensus. I should add right here that this information is provided for your entertainment: bushwalking and mountaineering are hazardous sports and you do them at your own risk. I accept none.

Copying these designs

What does this page offer? I am putting my ultra-lightweight designs here for anyone to copy for their own private use. In some cases I can make fairly detailed plans available, while in other cases the information is still being put into a releasable state. Even so, the ideas are there for free. I retain copyright over these designs, and commercial use is not authorised. If you want to make an item for yourself using my design, feel free. If the prospect is a bit daunting, I could be persuaded to make the gear up for you (given adequate time - sorry). However, no responsibility is accepted for what you do with the gear.

April 2012: I am trying to get a firm interested in commercial production. While this is happening the detailed plans are on hold. Sorry.

Design Details - how to get them

The tent designs were developed on various CAD systems, but the actual shapes have been described mathematically and come as spreadsheets of (x,y) positions along all the edges. Other details are given in the accompanying documentation. The tent poles and joiners, and especially the bent joiners at the apex of the poles, do get a little technical. A workshop may be needed. There didn't seem a lot of point in putting all the numerical data for the tents on this web site, so for the present send an email request to me at the address above saying which tent design you are interested in and I will try to send you a zip file. If you want the design altered slightly, let me know and it may be possible as some of the designs are mathematical. The zip file will contain both the spreadsheet data and some documentation describing how to sew the design together. Doubtless this will be incomplete, so you may need to ask for further hints. Some experience in sewing is needed.

The pack details are simpler and the information may be a little more sketchy at this stage. The pack bag design is simpler as it is mainly square, but the frame is very technical. However, a simple copy is possible using slightlky lower tech materials.

The sleeping bags are a different proposition again. Designing a sleeping bag is not that hard, but getting the really light down-proof fabric and the down is more complex. Both of the Australian gear repair companies (Venus and Rapid) can fill bags for you. However, I do not know what quality down they can provide. I am also working with one major gear maker on this: he may be willing to fill bags with top quality down for a reasonable charge as well. You can fill a bag yourself if you want, but be prepared to have a house ful of floatie down for the next week! For the rest, see the Sleeping Bag page.


Pillows - for comfort

One piece of equipment we all need, and use at home every day, is a pillow. But try to buy a realistic lightweight pillow in the shops, and face frustration! Most walkers try to use a bag of some sort, and stuff it with spare clothing at night. But every time the subject comes up in discussion, you find that no-one is very happy with the result. And when you are into the ultra-lightweight style in mid-summer, there may not be a real lot of spare clothing available anyhow! So the scene is ready for a good lightweight pillow.

In winter 2003 I wrote here "Yes, all this is leading up to the announcement that I have reached the prototype stage with a UL pillow. It is soft, as thick as a normal pillow used at home, and weighs about 75 gm. Field trials are progressing. More will follow." I have to admit things did not go as well as expected - surprise! I tried using inflated pillows of various sorts, but they were either very noisy or my head rolled around on top of them. So the project went into hold mode while I worked on the packs - my apologies to all who emailed me asking for details.

However, the latest version has been more of a success. Before describing it I should give some background. I have been using bits of open-cell foam from places like Clarke Rubber as a temporary pillow, but they were either too soft once warmed up or too hard (like the last bit I bought). So I had a look at the internals of a good Dunlopillo pillow. It is foam, but the foam is full of long holes like corings. I thought this might work with the slab of foam I had bought from Clarke Rubber (the heaviest open cell foam they had), and ran the experiment. This is illustrated in the following sequence of pictures.

I took a bit of thin-walled stainless steel tube about 25 mm diameter, sharpened it on end and mounted it in a drill-press. I imagine a pistol drill might work almost as well. Then I created a grid of holes on a sheet of paper, stuck this on top of a block of foam about 190 mm x 230 mm x 100 mm high, and did a long 'cork-boring' effort. This gave the left-hand picture. Then I wrapped a bit of Polartech 200 fleece around the foam to give the middle picture. Finally I put some ordinary poly-cotton sheeting around it as a pillow-slip, to give the right-hand picture. I prefer to sleep with my face on (poly)cotton rather than pure synthetic: it just seems more comfortable. This design worked very nicely: it held my head up all night, it did not make a noise, and it did not let my head roll around either. Normally the foam would soften when it gets warm, but this did not seem a problem here. It weighs about 100 grams, which is not bad for a good night's sleep.

Some words of advice should you want to make one. Sharpen the tube so the cutting edge is on the outside of the tube and the hole it cuts is not smaller than the tube. If the light soft foam grabs on the outside of the tubing you will discover just how strong the foam can be as it rips the tube out of the drill chuck. Make sure the tube is mounted squarely in the drill: if it flails around it can be a bit (too) exciting. Make sure you drill square: if the holes merge at the other face it is not nearly as nice a job. Be careful: the sharp spinning tube can be lethal! No responsibility accepted here!


© Roger Caffin 6/6/2002