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16mm EVA
12/06/2020 at 04:42 • 0 commentsA combination of 10mm & 6mm sheets arrived, along with rounder plastic to try to reduce the wear. The 10mm sheets can only be cut with an xacto.
The last 12mm pairs compressed into paper. Still looking for a denser foam.
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Luna enhancements 3
08/06/2020 at 07:26 • 0 commentsBack to the 2 triangle farsteners. A new theory emerged that larger ribbon loops might make the farstener areas more flexible. 2 loops can be enlarged, but a 3rd loop is too close to the pavement. It would have to be sewed instead of hot glued. Also, eliminating the cord locks & fixing the toe strap length might improve the toe strap. The lion paws have to heal from the last experiment before trying these on.
Rubber cement has done a better job than hot glue at farstening the suede to rubber. Suede continues to work well at avoiding blisters from the rubber. Lions wash these after every run.
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More luna enhancements
06/08/2020 at 04:15 • 0 commentsThe suede pieces from 2 years ago were taken off the xero sandals, after being untouched for 2 years. They looked absolutely ancient. It really was a long time ago when the sandal experiment began. So much of that time was spent commuting, it felt a lot more recent.
The suede ended any blistering from the rubber, but with increased running distance came another hot spot from the triangle farstener.
This was a total failure. Hot gluing the straps makes them more abrasive.
Another shift of the toe strap closer to the center.
The cord locks from strapworks had strange, unused plastic bits which were ground off. The lion kingdom suspects a smaller, more round shape is easier on the paws.
The toe strap made of 9 strands of white mason line was found to be too aggressively slicing lion paws, so it was popped out. It held up surprisingly well, but to reduce the amount of pressure on the lion paws, it had to be thicker.
A 2nd hole was drilled with a 5/16 bit. It was found that the flexibility of the rubber prevented the hole from growing to the size of the bit.
The traditional 2nd toe strap was put in. This strap was made from 9 strands of #18 yellow mason line. It fit through the holes just like the 9 strands of white mason line, despite fears that yellow mason line was thicker. Maybe the original hole stretched from being worn. This was 2 more strands than what the EVA sandals used for their toe strap. The EVA sandals dropped to only 7 strands of yellow mason line, to allow it to fit through unmodified cord farsteners.
It came out surprisingly well isolated from the pavement.
Another lace design taking out 1 of the plastic triangles went in.
A slight twisting of the ribbon & protruding section ate lion flesh. The new toe plug worked quite well, though.
Ribbon laces have been quite a failure compared to string bundles, but there's no way to make a string bundle big enough to support such a heavy sole & fasten it. The sole has to be lighter or it needs a fabric upper. Lions have started leaning towards designing lighter soles that are better at buffering rocks, rather than trying to enhance the lunas. -
Replacing toe plugs
06/06/2020 at 07:15 • 0 commentsSo with no need to commute, the lion kingdom washed its sandals after every run & the white toe plugs quickly became frayed. It was time to replace them with yellow string, which despite being more abrasive, would hopefully not fray.
Replacing the toe plug in permanently adhered soles was hard. Your biggest allies in this part of the battle are the AMD knife, tweezers & blade screwdriver.
To remove the frayed string, cut 1 side of the toe plug near the sole where it isn't frayed. Wiggle the other side while pulling it & push the cut side with the knife. The polypropylene protects the foam from pulling.
Then push the new string in a hole, 1 loop at a time & under the polypropylene with the knife. Use the tweezers to pull the loops out the other side. Use the screwdriver to keep the polypropylene in place. It's helpful to mark the position of the loops on the string.
This process passes 4 loops containing 8 strands of string. Only 7 of the strands are used, since only 7 strands of yellow string fit in the unmodified farsteners for the old toe plug. For the yellow string, the farsteners should be modified & 8 strands should be passed through, exactly like the white string.After trimming the string & CA gluing the ends, the sandals are ready.
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Luna teardown & enhancements
05/11/2020 at 00:11 • 0 commentsIt was clear that the lacing was useless, so it was time to tear it apart. The lion kingdom desperately wanted to stick with heal straps for such a heavy sole, while moving to string for the toe plug.
This led to the strapworks gootube channelhttps://www.youtube.com/user/Strapworks/videos
There actually is a method to fastening straps. Eventually ordered a pile of random fasteners from them instead of amazon.com. Amazon.com tends to sell only large quantities of 1 type of fastener for a lot more money. Sometimes the only plan is just to try out random ideas.
2 weeks later, a bag of farsteners arrived.
The biothane was a waste, too stiff for any use besides maybe a strap on a vehicle. It was all a casualty of not being able to see things in person.
https://www.strapworks.com/Blue_Water_Tubular_Nylon_p/wsr-nyl-bwt-058.htm
The best webbing has been 5/8" neon green tubular nylon. The tracer marking may look ugly, but it's useful for measuring. The prototypes began, heavily relying on hot snot for temporary bonds.
The new toe plug was made from 9 19" long strands of #18 white masons line. This was the maximum thickness which could go through the hole. All the white string will be replaced by yellow mason line because it frays when it gets wet.Since past sandals had no indentation for the toe plug, lions had to make the toe plug loop around 2 holes. The Lunas have an indentation for the toe plug, allowing a single length to be hot glued in. This will be replaced by epoxy with some kind of mold release so it can be removed.
Lions have black toes from wearing shoes.
A simple cord fastener allowed the toe plug to loop around the side farstener. There are a few other places to loop it. The holy grail of sandals was achieved: independently adjustable toe plug, rear heal, & front heal in a minimally abrasive system.
The best design thus far achieved independently adjustable toe plugs & front ankle straps, no chafing from the plastic or the straps. The key is to keep all the farsteners as close to the ankle as possible.
https://www.strapworks.com/Plastic_Strap_Adjusters_p/psa.htm
The ages old strap adjuster, 0.75" - 1", proved to be the best way to make an adjustable front ankle strap. It could use some extra rounding of the edges to prevent chafing. The rear ankle strap will eventually be a fixed length, as it was on the EVA sandals. All suede was eventually replaced with nylon straps.
The rubber soles eventually proved to be the mane cause of blisters. The traditional solution is a layer of suede on the rubber, but these are already super heavy soles.
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Luna sandal details
05/09/2020 at 21:30 • 0 commentsThe lion kingdom bought the most expensive pair of sandals in lion history to aid its quest for the ultimate trail sandal.
The heal bumper is some kind of neoprene sewed onto fake leather.
The sole was the only differentiating factor lions could find between their $80 & $110 sandals. It's much softer than Vibram's 1mm soling material but thicker. The lace fasteners go below the sole, so they'll wear out.
The sole contains Vibram rubber, probably a neoprene cushion, & a harder upper rubber. Also note the plastic lace attachment is sewed together.
The lace is a single nylon tube of some kind. It doesn't use velcro but merely a fabric bungy cord of some kind to squeeze the end together.
Fastener for toe plug & heal strap. It adds friction to keep the 3 lace segments the same size.
Heal to sole fastener. Plastic to withstand the wear from being exposed under the sole, but sewed instead of glued or riveted. It adds friction to keep the heel the same size.
The toe plug has a fabric piece joining 2 nylon lace segments of different diameter. The fabric piece is the scene of a lot of sharp edges. The lion kingdom's 1st idea was to wrap it in scotch.
It was a useful example of how to manage a flat lace. Lions prefer separate laces for the toe plug & the heal. No fasteners should be exposed under the sole, since no plastic is as durable as Vibram soling material.Obviously the soling material came from Italy & the plastic bits came from China, but there was a lot of sewing that could have been done in Seattle.
3 miles in those ended badly. The areas of the nylon lace system which were wrapped in bungy cords & fabric attacked the lion paws. The entire toe plug was a knife. The plastic side fasteners rode up on the sides of the sole, creating a blister causing bowl. At least the soles were effective at defeating rocks. There won't be an easy off the shelf trail sandal.
The nylon lace might be salvageable if it has a less abrasive covering on certain sections. The side fasteners need to be replaced by suede or something soft. It might involve sewing. In the worst case, the entire lace system can be replaced by tried & true multi pass string.
Rigid plastic fasteners which are fixed to the sole are how they prevent your paws from sliding around on hills. Shoes trade stiffness for covering your paw in a larger area of fabric, so to get the same stability from a softer material would require turning the soles into shoes. -
2 more pairs
05/03/2020 at 06:37 • 0 commentsThe mane addition with these sandals was extra bits of rubber in the highest wear areas.
The lace ends were taped together into loops until they fully stretch. Then, the laces may be cut again & hot glued or left as loops.
The photo record says the last pairs were built in April & Aug 2019. The April pair was only used once per week & went at least 400 miles. The Aug pair was used 5 days per week & went a lot farther. They finally got replaced, today. The mane cause of death is the soles wearing down. While the EVA quickly compresses into cardboard, the compression hasn't been the mane problem. Alternating sandals for every run may undo some of the compression.
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Cracked rubber
05/02/2020 at 23:04 • 0 commentsThe dream of improving the sandals continues to give way to the need to keep the current fleet alive as it wears out.
It came to pass that a $40 sheet of soling material became cracked from being stored in a folded position. This sheet only yielded 2.5 pairs of intact sandals, but lions have realized soles can be created by gluing smaller pieces.
In the last 2 months, a rise in the need to fabricate face masks from fabric caused a lot of men to start sewing.
This got the lion kingdom thinking more seriously about sewing straps instead of strings.
Reviewing the Luna sandals offerings, their top line sandals are now $120 instead of $200. That's cheaper than what lions paid for Hokas. Their bottom of the line is $80 & sold through resellers. They're all using a single toe plug instead of a toe strap. The toe plug & heal all use nylon straps. The nylon narrows down before inserting between the toes.
As it was when lions dropped $40 on a zeroshoes pair to get started, the trail sandal begins with dropping a certain amount on a Luna pair.
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Trail dreams
09/21/2019 at 09:36 • 0 commentsThe current design has worked well on roads, as long as there are very few rocks. It's pretty bad on trails. Making minimal sandals bearable on trails has long been an impossible dream because they would have to be heavier & this would make the toe plugs more painful & cause more chafing from the string.
As long as the weather wasn't humid & the strings weren't too tight, lions have gone 25 miles without any chafing from the latest toe plugs & strings, without any tape, but they do result in scabbing where the toe plug enters the foam. A trail sandal needs to have straps instead of strings to distribute the increased weight & handle sideways forces. The lion kingdom believes suede straps might do the job, but these require a quick fastener for straps instead of cords. Velcro has proven very short lived in sweaty environments.https://www.amazon.com/10-Inch-Lever-Plastic-Buckles/dp/B00GS9L5U6/
Levered buckles are intriguing but bulky. It may be the good old fashioned
https://www.amazon.com/Plastic-Tension-Triglide-Backpack-Suitcase/dp/B07797M878/
backpack tension lock is the best solution. Unlike a backpack, they wouldn't require taking the sandals off or odd contortions to adjust.
For rock resistance, a combination of thicker soles & a hard inner plastic sheet might work.
As much as stock materials have become unavailable anywhere outside China, there's still a place selling 4mm & 6mm vibram sheets to crazy guys who build shoes outside China.
https://www.leathercaresupply.com/collections/soling-sheets/products/vibram-7175-cherry-soling-sheet-shoe-boot-sole-repair-4mm-6mm-35-x-11-black?variant=49408936213
The trick is adhering the inner plastic to the system. The adhesive is permanent & thicker soles are expensive, so it would be a lot more expensive than designing the road sandals.Digging up the 4mm soles from 1 year ago revived the memory of those early days. Many months were spent building the early sandals.
The polypropylene bonded slightly to foam but not at all to rubber.
1mm acrylic was cheap but immediately shattered when cut. It would never do.
The ideal plastic would be laminated in rubber like most modern gadgets. That's done by having holes in the plastic for the rubber to pour into.
Rather than find a material porous enough to adhere, the leading theory is having a foam layer, polypropylene, foam, & sole, with the sole adhered to foam as it is now. The 2 foams would have to be held together with string separate from the straps going to the paw. It may be a 6mm sole with no rock plate is good enough.
The straps would have to be glued to the bottom foam, via the outside rather than via holes. The trail sandal also needs a suede cover on top of the foam to increase grip when it's wet. If everything is glued, it's real expensive to try again. Perhaps, test articles can have string fasteners around the outside. -
Death of cheap 2mm rubber
04/21/2019 at 17:47 • 0 commentsIt wore through a lot faster than the expensive Vibram. The string did well, since these were only worn for 151 miles.
Other changes would be reverting the length to the original Walmart size, since the lacing was never accurate enough to precisely center the paw. The string can't be trimmed until after some running. Softer adhesive needs to be used to terminate the string.
Finally had a sole fall completely off because of the hot glue becoming disengaged. It could have been hot pavement. The decision was made to use E6000 to adhere the soles from now on.
The mane problem is E6000 reacts with rubber to cause it to warp. The 1st attempt to deal with the problem was tacking the outside with hot glue after making a bead of E6000 on the inside. This still didn't produce a durable seam & made it heavier.
A new Vibram sheet costing 25% more than the last one arrived. Not sure if it was a tariff or Pandering Powell.
Getting the ideal seam requires a jig. Cut up the last of the flip flops to press the seams together while not pressing the string. It had been a long time since lions wore those flip flops for 13 miles & even longer since they were a radical design. They lasted 50 miles if they were lucky.
Glue pattern
The plastic hardware was rounded to try to reduce the wear on the sole.
Latest measurements of the plastic bits. They have to be long & narrow to prevent the string from getting under.
Gravity was not enough to do the job & they still warped. Wood clamps would be required. Chinese are manufacturing magicians.
Hot gluing over the CA glue areas ended the chafing from those parts. The white string caused less chafing than the yellow string, but frayed more.