 So I'm trying to make a pair of sandals and sandals with cork soles and because a well known brand of cork sold sandals doesn't tell you how to do it on the website for some reason I have to do some experimentation to figure out what is the proper mixture of cork to liquid latex. So the sandals I'm trying to make from bottom to top are a rubber sole and then a layer of jute twine so like burlap and then cork and latex which is the actual footbed and then another layer of jute twine or burlap and then actually what your foot will touch the footbed which is suede never mind the little boy over here who's playing which is suede and then they'll have the straps that go over made of leather so right now what I'm trying to do is experimentally figure out how much cork I should mix with how much liquid latex to form the best sort of sole that I can. I've taken corks cut them in half cut them in fourths and then sliced those up as small as I could and then I ran them through a blender basically until they're about the size and consistency of grape nuts but they're much springier. So now what I want to do is take these crumbs and mix them with liquid latex. I'm going to pop these into a muffin tin and press them and let them dry and then when they're done I can have some samples of what the footbed will be like so I can figure out which is the best consistency like I said I don't know how much liquid latex I should be adding. So what I'm going to do is I'm going to measure out 10 grams of cork which is actually quite a lot of cork because it doesn't weigh anything it floats so it's about a quarter cup for those of you playing along at home but 10 grams I'm doing 10 grams because it's a nice round number so then when I add five grams of liquid latex I'll call that 50% okay so here's 10 grams I'm going to pop this into my muffin tin but first I want to lay out put in a sliced up coffee filter so it's not going to stick and will come out pretty easy afterwards now I'm opening up my liquid latex and this is available online it's used in making costumes and prosthetic things it's a natural product it's just liquid it's just latex and water so I did see on the website of this famous brand that the dough that gets baked into the cork board or cork foot bed looks like a cookie dough or something like that all right that five grams will not do let's try 10 grams there we go there's 11 grams let's see how that does so it looks like a fairly wet cookie or bread dough is the consistency I'm aiming for I put this in here as firmly as I reasonably can all right so there's one so let's try it again with let's try 15 grams let's try 20 grams I'll do 25 so I just did 25 I need to do 30 so right it's the next day so these have dried out I hope so I'm gonna slice into them one by one and see what the inside looks like so here's the 10% or 100% so just as much 10 grams latex with 10 grams cork that's pretty good actually surprisingly good this is 150 percent so 15 grams latex with 10 grams cork 20 25 25 grams of 250 percent by way and these are getting much rubberier like I can clearly tell that the majority of the structure here is rubber with just a little bit of cork kind of floating in the rubber so 25 25 grams or 250 percent far too high and you can see this flapping back and forth here this is just giant ball of latex yeah that's just latex with some cork in it so I think 15% is reasonable or 15 grams is reasonable I was kind of from the outward feel I thought 20 or 200% would be the the winner but it's actually really spongy I don't know if I want that under my foot deforms yeah I think if I compress this a little more I think I could go with 150% so you see how 150% bounces back there's only 100% it deforms and stays deformed a lot more and tears more easily I start to tear it a little bit comes apart where's the 15 or the 150% there's a lot more there so I think 150% is my winner I cut out and drew the depths of each location on the foot this is going to be the press that goes in and pushes the form into the top of the of the sandal and then I sanded I cut out with a router some flat areas where they should be flat and some depths and then I sanded between those areas to make this form of a shoe and you see here that still has to be cut out to make the the toe grip I'll do that with a chisel I've got my form and I did a little bit of sealant in there so that the latex doesn't stick to it probably still stick to it because you know my luck so now say and these sandals have a layer of leather and then jute twine and then cork and then another layer of jute twine so what I want is I'm going to build these backwards and then put these forms into here but they're a little tight so what I have to do is put the leather on the way it goes and I got to make sure that the leather touches all of the rim there cut your leather and your jute a little bigger than you think you need it because if you cut it small it's a little harder to get it all in there evenly I'm running into that problem I get this as sandwiched as even and nice as I think I can put it there start to push it in check and make sure that the see how my jute isn't covering all the way I got a little to one side I try and line that up again slide that over it's kind of funny I lived in Germany actually not too far from one of the major factories where Birkenstocks were made but I had no idea otherwise I would have gone so that's pretty good I got a little bit missing there try one more time doesn't cost anything to try again other than a little bit of my sanity trying this over and over when I get it nice and lined up I'm gonna go ahead tap this in I want it to be pretty tight so mission accomplished and I want to tap this down till it's just flat not ideal so you have my jute didn't cover that's why you want to make your jute bigger bigger than it should be and there I've got the excess jute that should be right there shoot I don't think I haven't enough extra let's try see if I can get the other one that's pretty good so there are some spots where it's concave like here in the arch support so I'm actually going to use vise grips and pull the leather a bit tight in that area to try and pull that leather down just so there's not a when I push the cork in here it's not fighting against a lumber and then there's a concave part there behind the behind the toe for the toe to grip so the sandal doesn't go flying so I'm just gonna push down and make sure there's plenty of slack and now I'm gonna take this inside and push the cork onto it okay so now I've got my form ready to go all I need to do is mix up my cork at a ratio of two to one that means for every gram of cork I'm doing two grams of liquid latex I need to put it into the form put the the jute twine the base layer on there put the top on and squish it and to squish it not only am I going to use wing nuts here on the bolts I'm gonna put it in my cider press and really press the bejesus out of this thing so let's get going let's see how many grams I've got here I'm putting in more grams than I expect I need rather have it flow out and have extra rather than have voids or too little yep just just over 4 ounces not even 4.1 so 114 grams and now I'm gonna add 228 grams once I get this added and here are my bottoms marked with B making the well in the center 228 grams here we come it's kind of like paint because paint has latex in it so this is a little bit of a paint consistency 200 15 17 18 19 28 oh 29 I want one gram over so sue me all right now I'm gonna mix it around I get a dough like consistency there's ammonia in this it stings the factory at the factory where they make these sandals I'm using wood which will probably absorb water will probably dry out faster which is good all right now I've got this mixed now it's time to put it into the form push it in really get it in every crevice and I think I've got it pretty well pressed into most places I am going to kind of mound it up in the middle so that when I press it down it'll push out and in and fill in all those crevices hopefully I don't end up with platform sandals with too much in there I'm hoping it'll squish out if it doesn't belong in there there's my hope I mean it's been a couple minutes it's still plenty workable plenty pliable all right I think I have a pretty even amount on both of these so now take the bottoms set them on now I set this plate on just make use of the old cider press the first I'll press the whole thing together and then I'll move on to press each individual foot each time oh as I tighten this I will tighten up the tighten up the screws all an experiment but I've gone down a good quarter inch already I anticipate that's a fair amount of pressure but spread over two feet so now once I get these tightened up we'll let the pressure up and then I will do this over each individual foot okay so one website the official website says that the souls are baked at 100 degrees Celsius for a few minutes and then I found a newspaper or a magazine article that said they went inside the factory and on that tour they said they were baked at 80 degrees for 10 minutes 80 degrees Celsius for 10 minutes and then left to left to cool at around 70 degrees for 24 to 48 hours so right now I have my oven on warm which is probably over which is probably over 100 degrees but I'm not using a metal form I'm using a wooden form so the heat's gonna penetrate a lot slower and and not as well so a little hotter for me is probably okay so I'm just gonna pop them in my oven on the lowest setting and I'm just gonna turn it off and then I'll just come back tomorrow morning and we'll just see how that works out of and off so on second thought I think I will turn this on for about 10 minutes I'm gonna set a timer and I'll just turn off and then I'll let it set I just want to make sure it does get up to temp so that latex really vulcanizes inside all right now it's time for sandal assembly but first I got to cut up this mower tire to get the tread off the bottom now mower tires often have a much thicker tread this one's pretty worn out I use a mower tire instead of a car tire because they're not steel belted other than those living in Guatemala and Mexico if you make sandals out of tires as the tread don't use car tires because those little wires the steel belting in there will work through and stab you in your foot whereas a mower tire is just rubber and it's got a layer of fabric belting in there which won't bother you at all that's plenty of tread for lots of sandals now for the next steps there's a lot of videos on YouTube from cobblers who know a heck of a lot more than I do about attaching soles and uppers so if you just go on to YouTube and look for re-soling Birkenstocks or refurbishing Birkenstocks you can definitely find videos with more information than I have what I'm using is a contact cement this is Plyobon 25LV industrial contact cement it's not you don't have to use that you can use whatever you want but that's what I found at my hardware store so that's what I'm using so what I've got are my my soles which came out they're okay I'm happy with the footbed I had to build up the back here because the when it came out of the form it tore so I had to kind of rebuild that but most that's going to be under the leather and this is deer hide that I tanned a couple years ago and then I dyed it with with walnut with black walnut like you saw so basically I'm going to use contact cement to attach this leather upper to the sole and then I'll have my little sandals I still have to cut a little bit but I want to wait until I put them on my foot to see how much I need to cut this might be a good time to plug my other video about making wooden shoes this is a wooden clog a sub oh or whatever you want to call it if you're interested in seeing how I made these and I've been wearing these all summer check that out but is a video about making a Birkenstock style corksold sandals so let's keep doing that now comes the stinky part I want to put contact cement everywhere that's going to get connected this stuff stinks and if you watch the cobbler's videos I've got these giant glue pots which look pretty stinky and gnarly it's actually not that porous now it's got a latex right all infused through this jute twine it looks pretty cool actually I think if I did this again I wouldn't go so hardcore on a foot shaped form instead I would make a sheet of cork latex infused cork and I would push them I would just make a big rectangular sheet of it and then I would cut my foot shape out of it now is that as good as a Birkenstock absolutely not it's not formed to your foot it's not got that nice shape but it's a lot more manageable at home so next year when I replace these soles that's probably what I'm going to try and do but this year I got this foot formed or maybe I would just push my my little foot forms into a rectangular square of it rather than making a shoe-shaped rectangular form you saw how much trouble I had getting it out of there so so there's no big rush because you're supposed to put on a layer and let it dry this thick layer on these more porous sides and it takes not much time once I do the contact for these to be cemented but it takes a week for the bond to be fully set up so I'm not going to wear them right away now I do the same thing to these guys so it's been an interesting process I didn't expect my results to come out as nice as a prefer as a real Birkenstock and they won't be I think I can already guess that my conclusion is if you want Birkenstocks you buy them you can make the the cork and latex material is actually pretty cool I really I really like working with it it's got a nice smell and a nice consistency to it it's just a pleasant a pleasant thing to work with this stuff not so much the forming is a pain and unless you have the right things to put the pressure on you're not going to get as as durable as a footbed I don't think as I was able to make here I mean we'll see how durable it is over the next year but yeah it's been a nice experience and I appreciate the when I buy my next pair of Birkenstocks I will definitely appreciate the the price a little more I've done a lot of research into this I actually have a playlist on my YouTube page here and you can look at some of the different videos that I watched of disassembling Birkenstocks re-solding Birkenstocks and then whatever useful information I could get from the Birkenstock company itself unfortunately the most useful video was a documentary made by Prozieben Galileo which is a German documentary not documentary it's like a TV magazine program that I I used to live in Germany so I speak German and they had this great video and they went inside the Birkenstock factory and it was great and super useful and it was online like six months ago and now it's gone it's been deleted which sucks because it had it showed them put it assembling and putting together Birkenstocks and now it's gone so I had to remember what I could remember yeah it's been a it's been a neat experience I learned a lot about Birkenstocks and I think that cork latex mix I think that's a useful a useful mix to know how to make it seems like it I'm gonna get some latex gloves here I'm starting to get a little bit tackiness on my fingers and I do not want to bond these lowers these uppers or lowers to my to my fingers forever as excited as I am about them I don't want to wear them as gloves for the rest of the day so I'm cutting this a little loose because I can always trim it up perfectly once it's glued on Birkenstocks often wear out on the souls these will definitely not wear out these will outlast you'll definitely outlast everything else so I think I will put a second layer on the leather and then try and attach it and cross my fingers that I don't mess it up all right I decided to get my forms I'm gonna reuse those to help keep pressure on these things I don't think I can really fit this in it's too tight what I can do is put my back in here and I'll have a lot of nice pressure to push the leather on where it should be hopefully without deforming it it says to keep it under pressure while the blue dries so I did cut the leather so that there would be less overlapping or as little overlapping as I could figure out on the bottom because you don't want little lumps under your feet if I hadn't cut it there would be lumps where this folds over and touches you know runs over itself there's a little bit of overlapping probably could have cut it even more aggressively but okay well I'm gonna go find some way to press these a little longer and more in a warmer spot and then we'll continue on with the rest of it okay so now I've got the uppers glued on and the I have put a coat of the contact cement here and here and so now so now when it's fully dry now I'm gonna add another coat to it and then stick these on and just kind of want to just kind of want to dry place them to make sure that they'll have a good good coverage everywhere and I'll be able to just stand on them so I'll just slide my feet in once I get them where I want them and I will just stand there for a little while to help set them and then I'll put some weight on them I've taken the rubber tire and I've stretched it the other way to try and loosen it up a little slide my foot right in I'm not worried about the excess here I'm gonna cut that off with a sharp knife once it's all dried as I do it I'm standing on one foot to put all my weight on the one I just did now I'm gonna put some more put some more weight on these things I've got little bits of wood that I can kind of fill up the space with I'm just gonna put some weight on top of them okay so now for weight I'm doing I'm gonna lift up my table slide these under and then I'm gonna slide wedges underneath the toe and the heel so that there's plenty of pressure on these things okay 24 hours so now my soles are about as glued as they're gonna be it'll continue to set up over the next seven days but most of the most of the strength that's gonna be there is there so now I'm going to take a sharp knife and very carefully cut the excess plastic off or rubber off leaving hopefully the leather and everything else intact cut my finger not too bad time for mandate I'll be right back now I need to do the strap across the top and they're largely done