Making a UHMWPE Sled
(Ultra High Molecular Weight Polyethylene)
My new sled ready for action
My new sled, although fairly expensive to make, weighs only about 8 pounds and has almost no friction on snow.
Here is how I made it, complete with errors and lessons learned.
- 1/8 inch UHMWPE 16 inches wide by 8 feet long
- 2 3/4x3/4 inch square ash 8 feet long for the gunnels. 26mm Chicago bolt and 3/4 inch #6 truss screw
- 3 3/4x3/4 inch square ash 14 1/2 inch long for the thwarts.
- 1 16 inch long hardwood for the front bumper
- 1 3/4x2in hardwood 14 1/2 inch long for harness strip.
- 2 SS eyelets, two SS washers and 2 bolt caps for the harness.
- about 24 3/4 inch long SS truss screws to attach the UHMWPE to the wood. Truss screws have a lower profile than standard.
- 12 brass 20-26mm chicago bolts for primary fasteners.
- 1/4 inch wood doweling and waterproof glue.
- at least 30 feet 1 inch webbing, 16 aluminum pop-rivets, 6 ladder-locs
The SteamerShowing a cheap and simple home-made steamer designed for doing the first few feet of the gunnels. Showing the opening to allow for some steam escape.
Materialsolder non-metal electric kettle
3 feet of 1.5in plastic pipe
45 degree fitting
2x4 for bracing
small amount of silicone caulking
some automotive wire
Soak the ash in warm water for 24 hours before steaming. The basic rule for steaming is 1 hour per inch of wood. As my gunnels are 3/4x3/4 I just steamed for one hour. I've been told that serious over-streaming can permanently damage the wood fibers. I only wanted to bend the first couple of feet of the ash gunnel, so I only needed to steam the first 3 feet.
The picture shows the set-up. Notice the 1.5 inch hole cut in the top of the kettle. This allowed me to add more boiling water via the spout. Adding cold water to the kettle will stop the steaming process so only add boiling water. The rag in the spout acts like a cork but is easy to remove when needed.
Stuff a cloth at the top of the steamer to partially close off the top. Stuff such that only about 25% of the steam should escape, the rest condensing and running back down into the kettle.
The JIGThe jig was nothing more than a piece of plywood, six small blocks of wood and a longer piece of wood further down from the curved area. The curve on the jig should have a piece of plywood or metal to smooth out the bend. Rounded the small blocks helped as well. My curve was based on a 10inch radius. I also wanted about 10 inches from the top of the curve to the base. Ended up with about 9.5 inches.
Tips on building and using the jig.
- Start bending from the top of the gunnel. This gives sufficient leverage at the tip.
- Trying to clamp the tip last won't work.
- Use a strip of plywood on the clamping side to avoid damaging the ash with the clamp. This also helps smooth out the bend.
- There is no such thing as too many clamps.
- Having a second pair of hands is really nice during the bending phase.
- A few small wedges can be used to tighten up the curve if needed.
Assembling the SLEDAligning the gunnels and thwarts before drilling. Showing the dowel and Chicago bolts. I decided on fixed thwarts rather than letting them float. As screws don't hold in the ends of wood very well, glued dowels were used. The harness attachment bar was originally a hockey stick. It has one wrapping of fiberglass cloth and inexpensive epoxy. When pulled, I wanted the attachment point low enough that the sled would not dig in but yet high enough that I wasn't lifting the front. I settled on 3 inches vertically from the base. The bumper should cover the ends of the thwarts.
Underside of the toboggan showing the harness attachment eyelets, chicago bolts and SS screws. Closeup of the top showing the Chicago bolts, bumper and harness attachment bar
Scuppers were routed into the ash gunnels, front and middle thwart. Scuppers, of course, being used for tie-down points. I sewed, glued and riveted loops into the straps and then just slid them over the gunnels before affixing the gunnels to the uhmwpe. The rivets are flattened aluminum pop-rivets; the glue is used to protect the sewing.
A closeup of the scuppers and strapping loop.
The 4 tie-downs at the front half are simply straight straps with ladderlocs. The back two are X overs so that they hold the wannigan and milk-crate on properly.
The blue milk-crate holds extra rope, repair kit and other odds and ends. It has a plywood lid with a piece of glued-on foam as to make a great seat.
The green tarp that covers my sleeping gear and extra clothing is the footprint for my tent. It is important that this stuff stays dry.
Isn't life grand. A leisurely lunch on a beautiful day.
If anyone has better ideas on building this type of sled or any questions, please drop me a line. I am thinking about a non-metal keel on the sled so that it won't slide sideways when crossing inclines. In the meantime, happy winter camping.