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Luna update
11/10/2023 at 01:10 • 0 commentsThe Luna sandals which arrived in 2020
https://hackaday.io/project/88623/log/177225-luna-sandal-details
went on to work quite well for walking but not running. They have the grip required to climb hills. The hot snotted fabric strap never had any problems as long as the hot snot was manetained & the laces were loosened before putting them on. There were dreams of printing a more robust attachment or looping fabric through the existing holes. There was a dream of sewing fabric on fabric instead of gluing.
The suede coverings needed washing after every outing. They eventually shrank & didn't stick on so they were left off. The bare rubber was acceptable for walking.
The original link was lost to time, but lions believe they were the mono
https://lunasandals.com/collections/luna-collection/products/mono-winged-edition-mountain-crystal
What was $80 in 2020 is now $110 so these will be the last lunas in the lion kingdom. It's not clear what lions will use for walking when they wear out. It might go back to shoes since walking was never subject to causing blisters. $110 was once the domane of top tier Hokas. The $140 Hokas are now $200 but inflation in a lion's mind doesn't equate to something getting less attainable, just the money being less valuable.
The replacement might be unpadded rubber since the only thing preventing the EVA sandals from being used for walking is compression.
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Pleather failure
06/25/2023 at 02:10 • 0 commentsMany toenails were turning to the dark side when sitting directly on 16mm EVA soles. Lubricant had a very negligible impact. The mane suspects were the foam compressing & riding up the front of the toes & the stickiness of the foam. The 12mm EVA soles were much easier on the toes.
The big needs in an upper material were grip in rain & blister reduction. Bare EVA was falling short in these departments.
The next step towards a better top material was spray adhering scrap fabric. This was a total mess. TSA gloves are definitely required. The fabric didn't all look the same color, but it all adhered. The lion kingdom's scissors are horrible at cutting fabric.
Completed pair. A better method is to glue an oversize piece & cut it later. The gluing jig could use more improvement, maybe cutting bits of angle aluminum to precisely fit. The big question was how the fabric would handle wear & water.
Early testing had debonding around the edges in heat. As for reducing blisters, fuggedaboudit. Fabric might even worsen blisters. It might be more tenacious than EVA & more like socks because it absorbs water like socks. Paws felt a bit raw after a hot 7 miles on fabric.
They might have reduced dry skin. They might still do better in rain, but that's a few months away. With the blister problem, fabric is still a total waste except for rain.
Elmers adhered where it wanted to & proved impossible to release without damaging the foam. Hot water helped.
Suede might still be the ideal upper material, but the original 1/16" suede https://www.hobbylobby.com/Crafts-Hobbies/Leather-Craft-Supplies-Tools/Leather-Pieces/Assorted-Suede-Remnants/p/80917344 is now unobtanium.
There are heavy suedes for a price. This piece is a 1/8" brick.
https://www.michaels.com/product/suede-leather-trim-by-artminds-10297420
The next material was fake leather.
Fake leather was Elmered on. It required some clamping. Suspect more permanent adhesion is going to require full clamping.
The big question was if the fuzzy side would adhere.
Cutting oversized pieces after adhesion didn't go any better than cutting them before adhesion. The scissors can't navigate around the laces.
Some sections didn't adhere. It was hoped enough would adhere to do some testing. Fake leather had a new carpet smell lions haven't smelled in 30 years.
After 8 miles on fake leather, it held on just enough but started to come off. There was no obvious benefit over EVA. It might have better grip in rain & might be less blister inducing because it dilutes the foam compression. It didn't noticeably make the sandals heavier.
The best solution might be a patch of hard material under the toes which doesn't compress. Making the entire upper out of hard TPU might work, but would be expensive.
The original reason for suede was to have a less grippy upper than rubber. Hard TPU might be too abrasive. There could be a hard TPU layer on top of EVA to even out the compression. Fake leather could go on top of the TPU to provide grip in rain.Pleather was not removable without taking off foam. A piece of cardboard went in under the toes with less tenacious school glue. Cardboard is not much stiffer than foam & it has problems in water. It actually yielded a noticeable improvement. Harder materials in that thickness get expensive fast. The long term solution is PLA impregnated with holes for adhesion. Carbon fiber would be the most expensive.
The thought has occurred of replacing the entire front chunk of 6mm EVA with a 6mm PLA section, but it would be expensive.
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A few hundred miles with cardboard showed it's probably a waste. The cardboard eventually delaminates as it gets wet, no matter what the adhesive is. Adding more adhesive to repair it makes it heavier. The leather itself might be hardened by adhesive alone.
Pleather ended up becoming very abrasive after 10 miles in heat & when it accumulated dirt. Blisters soon followed. Vaseline might be required, just like bare EVA.
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Death of a toenail
04/29/2023 at 00:27 • 0 commentsAnother toenail goes to the toenail in the sky. Not sure why the sandals eat toenails. The general theory is bare EVA is very sticky & too much stickiness in the toe area causes blisters under the toenails. You can't moisturize toes because moisturizer causes toes to stick. Simultaneously, dry toes get cracked & swollen which also kills toenails.
The leading idea nowadays is to lubricate the toe area but not use a moisturizer. Another idea has been to cover the bare EVA with suede, but suede is heavy. Suede has provided just enough stick but not too much & it's been immune to rain.
The journey to a more tenacious sole has been long & slow, manely because every option is expensive.
Lions wonder if vibram rubber has ever been remelted & cast into other sole shapes. The tooling might cost more than the rubber. The case could be made for casting 1mm rubber soles with just the right amount of lugs.
It turns out the 1mm vibram soles slide like glass on a freshly waxed mall floor. They really are bad compared to shorter life rubber. So ideas began to emerge of having a pair dedicated to less frequent trail use, with higher grip rubber. Maybe a PLA positive could be used to create a moldmax negative & that could be used to form a grippy sole out of rubber. There are very expensive rubber epoxies. Balloon rubber is the grippiest rubber. Natural rubber seems to be the key.
https://www.amazon.com/Rubber-Repair-Non-Slip-Soling-Bottom/dp/B08RB1CTBG/
There is 1.2mm sole rubber which calls itself anti slip. 15" x 11" is $10 bidie bucks. What lions really want though are lugs.
TPE has shown pretty good grip performance compared to TPU, but it's expensive. The latest idea is printing a lugged 1mm sole out of TPE & hot gluing it to the sole of a retired sandal. Maybe a pathfinder could be made of TPU to see if the lugs overcome the lack of friction. It would have to be printed in 2 halves & welded together.
The preferred lug design is just a regular pattern of square outlines.
Hot glue rivets would go in the holes.
In today's price of $60/500g it would be $6.
A pointier lug might dig in more & reduce the price to $5.
Then comes testing it. The only place demonstrating the traction is near the very end of a long mountain climb.
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New pair
03/22/2023 at 07:06 • 0 commentsNew pair of 16mm's after 9 months. Used the soldering iron to melt holes for the 1st time. There is a plan to make another pair just for testing sole materials. They'll be hot glued.
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2022 edition
04/25/2022 at 22:31 • 0 commentsThey're lasting 800 miles. The mane changes this year were reducing the rear lace to 10 passes of string & gluing the rear lace to the sole. The most time consuming part is cutting all the materials. Gluing 2 pairs takes 4 days because of the number of clamps.
The lifespan has been limited by large wear areas in the middle of the sole which would require a completely new sole.
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Mountain test 1
03/27/2022 at 00:55 • 0 commentsA long awaited test involved going up & down the mountain in 16mm sandals.
The uphill segment was all done on trails.
Only the last part of this section entailed using 4 paws. The rest of this section was gnarly but doable in the uphill direction.
Sadly, the sandals didn't have enough traction to attempt these 2 sections in the downhill direction. The downhill direction was much gnarlier. The laces weren't the problem, but the smooth soles weren't up to it. There are no lugged 1mm soles. Perhaps lugs can be glued on, but they're going to be heavy. The great challenge continues to be steep sand covered clay.
Steeper sections with exposed rock were doable. Rock hits in the downhill direction were painful. The downhills had to be slower than in shoes.
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16mm EVA #2
05/29/2021 at 19:55 • 0 commentsThe 16mm soles proved a decent compromise between speed & durability over 6 months.
Right paw compression was down to 6mm while the 12mm sandals compressed to maybe 1-2mm so the compression in both cases was 10-11mm.
Left paw compression of the 16mm was down to 3mm, so the 12mm sandals may be a case of the foam compressing all the way down to a solid, with still more compression to go.
Original 12mm compression.
Despite having more cushioning, the soles still wore out fast. They might have worn out faster because of the cushioning. They might have gone 500 miles per pair.
More proper clamping joined the next EVA sheets. Because wood clamps are so nose bleed expensive & the pressures on foam aren't very high, there's motivation for 3D printing a jig for gluing the pieces. Gluing sandals is just a very rare operation for such an investment in gear.
The 10mm foam was actually cuttable with ordinary scissors. Making holes in the full 16mm requires an exacto.
The 1st investment in cord locks in years. The orange ones look a lot better, but only fit around the toe straps.
Square plastic bits appeared to wear away the soles faster, so the they were rounded again. Extra glue was applied to keep them oriented.
The soles got a more aggressive clamping. Another 10 clamps are still required to do it right.
https://www.amazon.com/dp/B08RXW32H4
These are quite good.
The clamping led to the best edges so far.
Black soling ran out with the shortages in 2021. Extra patches will be glued to the worn areas as they wear out.
The laces swell over time, making the cord locks tighter. They're too loose when they're new.
The last set underwent a lot of patching on the soles to worn areas. They retained a lot more cushioning than 12mm. They have a few more miles left before being discarded.
Wear varied greatly, depending on the lacing variations & paw position. Right paws are getting beaten up more than left paws.
What's desperately needed are semi permanent adjustments for the rear & outside of the ankle strap. They don't have to be adjustable in the field like the existing adjustment points. Lions continue to dream of a 3D printed cord lock to fuse the 2 existing ones into 1.