How to glue rubber to leather

[deboardp]

I'm making a four sole sandal, three layers are leather, glued and stitched together. The fourth layer is 1/8" gum rubber, a full sole. What's the best glue for this? In my glue drawer I have Barge, Renia Top-Fit, Renia Aquilim 315, and Intercom Ecostick 1816B. 

The last one listed holds great when dry but the leathers separate when wet. They can be pulled apart. 

The shop is in my living room so i haven't done that experiment of soaking and pulling apart with the other glues. I'm thinking the water based glues will also not hold when the leather is well soaked but that possibly the barge will hold. Anyone know? 

The leather will be well roughed and the rubber, too. I have a one ton manual press for some pressure on it. 

Edited December 27, 2023 by deboardp
Sp, details

[Hags]

I tried the water based glues. Not as good for holsters.  They seem to not hold very well when wet molding. I went back to weld wood contact cement. We also used the rubber cement on conveyor belts in industry. I'd use the Barge.. Do it outside if you have to.

Edited December 27, 2023 by Hags

[deboardp]

I'll use the barge. I bought a twin fan window unit, reversible air flow, and put it in the shop window, blowing out, and I open a window in another room.  

[DieselTech]

Try some of this epoxy. It's a 24 hour slow cure flexible epoxy & is good stuff for bonding about anything. Rough your leather & rubber with 80 grit sand paper. 

Then apply a thin layer of epoxy to your rubber & to your leather. Then weigh your project down to cure over night. 

This epoxy goes a long ways & dont take much. 

It has a very mild odor too.

[Mablung]

46 minutes ago, DieselTech said:

It has a very mild odor too…

…giving it a considerable advantage, as far as pleasantness to use, over Barge and Tanner’s Bond. May have to try that stuff out once I run low on Tanner’s Bond. 

[DieselTech]

31 minutes ago, Mablung said:

…giving it a considerable advantage, as far as pleasantness to use, over Barge and Tanner’s Bond. May have to try that stuff out once I run low on Tanner’s Bond. 

Yeah it's worth trying for rubber to leather. That epoxy has a un godly shear & holding strength. It's slow curing so you got lots of time to work with it. It takes about 12hours before it starts to set. 

It stays extremely flexible in thin layers/application, yet has unholy pounds pre square inch holding ability. 

Edited January 25 by DieselTech

[Dwight]

4 hours ago, DieselTech said:

Try some of this epoxy. It's a 24 hour slow cure flexible epoxy & is good stuff for bonding about anything. Rough your leather & rubber with 80 grit sand paper. 

Then apply a thin layer of epoxy to your rubber & to your leather. Then weigh your project down to cure over night. 

This epoxy goes a long ways & dont take much. 

It has a very mild odor too.

My heavens and OUCH . . .  have to wait until I sell some more stuff before I can order it . . . 

May God bless,

Dwight

[Tastech]

May i offer my advice . As a shoe maker and repairer i glue rubber to leather all day every day . Its no big deal . Any contact rubber cement will do the job but some are much better than others . I use and recommend Renia Colle de colonge  .Apply on both surfaces and let dry for about 30-60 mins . With a heat gun or even a blow dryer heat the rubber piece then apply to the leather . Cut the rubber larger than the sandal and trim the rubber with a knife . At some point you are going to have to replace the sole  so you heat the rubber again and with pincers remove the rubber and replace . Using epoxy is not an option because it is brittle and will crack even the flexi stuff and will do damage when trying to replace the sole  , Also you have to keep the sandal in a press for 12-24 hours . Another option is to use a product called shoe goo . It is flexible but needs to be pressed as it is not a contact adhesive . I use shoe goo mainly for hiking boots especially the toe piece that returns upwards . To keep it in place i wrap a cut down bicycle tube around the shoe for a day or so . Either way contact adhesive is the best option . Yeah its a bit wiffy but so what  only smells for about 10 mins  and it wont kill you . I would also recommend you get proper sole rubber from a cobbler as it has a different composition than regular rubber and comes in an assortment of treads .

[Tastech]

the sole rubber from cobblers comes pre roughed on the glue side to make the glue stick to it  . rubber that has not been roughed can come unstuck

[deboardp]

1 hour ago, Tastech said:

May i offer my advice . As a shoe maker and repairer i glue rubber to leather all day every day . Its no big deal . Any contact rubber cement will do the job but some are much better than others . I use and recommend Renia Colle de colonge  .Apply on both surfaces and let dry for about 30-60 mins . With a heat gun or even a blow dryer heat the rubber piece then apply to the leather . Cut the rubber larger than the sandal and trim the rubber with a knife . At some point you are going to have to replace the sole  so you heat the rubber again and with pincers remove the rubber and replace . Using epoxy is not an option because it is brittle and will crack even the flexi stuff and will do damage when trying to replace the sole  , Also you have to keep the sandal in a press for 12-24 hours . Another option is to use a product called shoe goo . It is flexible but needs to be pressed as it is not a contact adhesive . I use shoe goo mainly for hiking boots especially the toe piece that returns upwards . To keep it in place i wrap a cut down bicycle tube around the shoe for a day or so . Either way contact adhesive is the best option . Yeah its a bit wiffy but so what  only smells for about 10 mins  and it wont kill you . I would also recommend you get proper sole rubber from a cobbler as it has a different composition than regular rubber and comes in an assortment of treads .

This is good news! 

Can I bother you for links?

For the Renia Colle de Colange? I couldn't find the receipt for the other Renia product I have. 

For the cobbler who sells(you) sole rubber? I couldn't find the receipt for the gum rubber I have, either. Is it crepe your talking about? I'd prefer something thinner and harder. I also bought some

I bought a sheet of gum rubber last year and have built my first sandal. I'm ready to stitch the three layers of leather. I'm still pondering a heel of tougher rubber as I'm assuming the heel will wear the fastest. I did buy some Goodyear Neolite heels in various weights and would like to use the thinnest one I have, 12 iron, for the heel. I hadn't made a decision on it because I didn't know how to glue it on. On the side of the heel it says 17/18 (my gauge confirms 17.5 ounces), 12I, W-4103, and SSI. This is a stiff piece of rubber. The gum is flexible. The tri- layer leather soles are stiff, too. I had been concerned that the wearer would feel gravel through them but now I doubt that. Now I'm concerned that they will be too stiff to be comfortable but also think they might loosen up, especially if I hand stuff some grease into the topsole. All three layers are 7/8 ounce, as well as the straps. All are firm HO veg tan

except the straps and midsole which are Tandy utility grade veg tan, a very nice side, only $129! 

 

[deboardp]

The gum rubber is visible in the above picture. This is the backside of the heel, which has been roughed up with a fine striation 

Edited January 25 by deboardp

[deboardp]

This is the sandal that's ready to stitch. I wet the edge all around so it would take a crease better. I'll stitch in the crease, no machine guide. I used the heavy awl to make crease lines around the straps to reinforce the slot areas. The water stained the leather and I'm hoping that the grease will overshadow that. 

Two of the slots look too big in the pic but that's because the strap is loosened. The straps have two reductions in it. It goes from 1-7/8" to 1-1/16" to 13/16". Snugging the strap will fill those slots. 

 

Edited January 25 by deboardp

[deboardp]

From the side...

 

[Aven]

Lisa Sorrell did a video on using Aquilim 315 with rubber. 

Its a Boot Life

https://sorrellnotionsandfindings.com/product/aquilim-glues/

 

Edited January 25 by Northmount
Added link to Lisa's site for Aquilim

[Mablung]

3 hours ago, deboardp said:

From the side...

 

Wow, that's thick.  Apprise us of how it feels on the foot.  Not at all likely you'll feel gravel through that (to me that's a detraction, but I wear quite comfortably shoes the sole of which consists of a piece of 1/8" crepe rubber topped with a 4 oz. piece of oil-tan).

5 hours ago, Tastech said:

May i offer my advice . As a shoe maker and repairer i glue rubber to leather all day every day . Its no big deal . Any contact rubber cement will do the job but some are much better than others . I use and recommend Renia Colle de colonge  .Apply on both surfaces and let dry for about 30-60 mins . With a heat gun or even a blow dryer heat the rubber piece then apply to the leather . Cut the rubber larger than the sandal and trim the rubber with a knife . At some point you are going to have to replace the sole  so you heat the rubber again and with pincers remove the rubber and replace . Using epoxy is not an option because it is brittle and will crack even the flexi stuff and will do damage when trying to replace the sole  , Also you have to keep the sandal in a press for 12-24 hours . Another option is to use a product called shoe goo . It is flexible but needs to be pressed as it is not a contact adhesive . I use shoe goo mainly for hiking boots especially the toe piece that returns upwards . To keep it in place i wrap a cut down bicycle tube around the shoe for a day or so . Either way contact adhesive is the best option . Yeah its a bit wiffy but so what  only smells for about 10 mins  and it wont kill you . I would also recommend you get proper sole rubber from a cobbler as it has a different composition than regular rubber and comes in an assortment of treads .

The suggestions are much appreciated.  I'm going to keep my eyes peeled for that Renia product, as I'm starting into making shoes (simple, minimalist designs, for the moment) so I can replace the soles easily).

[Tastech]

deboardp  ,  I am in Australia and we use different name products so links to products from my supplier would be of no use to you . Find a wholesaler of shoe repair materials in your area and source your materials from there . They will have a few different brands of high strength contact adhesive and various types suitable sole material of various thickness  and hardness . same goes for heel material . You may have to buy a full sheet of the material  , but if you are making a few pairs then it is economical do do so . Go to your local cobbler and ask some question and get them to show you various materials that they use . That way you will become familiar with what best suits you and you can then contact a wholesaler . One product that may interest you is the birkenstock EVA sole . Its 8mm thick and relatively soft yet quite tough . Its a good sole for sandals . The brand Vibram is also worth looking at . EVA or microcell is probably the best material for sandals because it is light weight and shock absorbing . There is also another type of EVA material that tapers from heel to toe . The heel is about 15mm and it tapers down to 8mm one the ball and toe . You have seen this before but probably never noticed it . You will see it on UGG boots mainly . Using the tapered sole eliminates the need for a separate heel . Brand is not important  because different brands use the same material formula . If you are not sure which material is better for you, experiment with different types. Keep in mind that you will need 2 coats of adhesive on the leather because the first coat absorbs into the leather .

By all means stitch the 2 layers of leather together but only glue the sole material on so it is easy to remove when a resole is required . If you choose a separate  heel of harder material then a few small nails for extra security is good .

Allow me to confess my dirty little secret . I wear crocs . There i said it . LOL Australia gets damn hot in summer and you don't wear proper shoes if you can avoid it . I like crocs because they are anatomically correct therefore comfortable , However i wear out the sole in a couple of years . New ones take a while to settle in so i resoled my old ones with EVA . Specifically the birkenstock pattern sole . I also do the same thing for my wife . She has shown her friends and now i get asked to do it for others . Even though the cost of a" birkencroc" conversion cost more that a new pair of crocs  people are loving it . Go Figure . Keep in mind that Crocs are not frowned upon in Australia  like they are in the US . Flipflops are king and Crocs are legendary . Birkenstocks was the preferred foot footwear of lesbians 20 years ago but now they have mainstream acceptance and i resole them frequently .

Fun Fact : Because Australians wear proper shoes only half of the time our feet are one size wider than the rest of the world . 

[deboardp]

On 1/26/2024 at 7:20 AM, Tastech said:

products so links to products from my supplier would be of no use to you .

Not so, not so! I'll look them up, read the specs, find out what you consider proper sole rubber. I have a sheet of gum rubber, 1/8" , thick, that I'll use on my first pair, the prototype. 

When I do get to it, I'll use two coats of Barge, just to see if the rubber will stay on. 

[deboardp]

On 1/26/2024 at 7:20 AM, Tastech said:

Go to your local cobbler and ask some question and get them to show you various materials that they use . That way you will become familiar with what best suits you and you can then contact a wholesaler . One product that may interest you is the birkenstock EVA sole . Its 8mm thick and relatively soft yet quite

We don't have cobblers in the states as far as I know. There's a shop that makes custom shoes but I doubt that they do repairs. Their stuff looks made for millionaires. I expected that someone would ask me if I'd kindly take my scruffy self down the road, and please don't touch the shoes! Although quite perfect looking, they also looked too stiff to be comfortable. 

When I was a competitive road racer in my 30's during the foot race craze in the 70's here in the states, I used Shoe Goo to build up my Nike Elite racing shoes at the heel. Great stuff. I still have a half full tube in my survival gear. 

[Wepster]

2 hours ago, deboardp said:

We don't have cobblers in the states as far as I know. There's a shop that makes custom shoes but I doubt that they do repairs. Their stuff looks made for millionaires. I expected that someone would ask me if I'd kindly take my scruffy self down the road, and please don't touch the shoes! Although quite perfect looking, they also looked too stiff to be comfortable. 

When I was a competitive road racer in my 30's during the foot race craze in the 70's here in the states, I used Shoe Goo to build up my Nike Elite racing shoes at the heel. Great stuff. I still have a half full tube in my survival gear. 

There are probably a hundred cobblers in New York State alone (one source states 7000 in the US). There is one in Amsterdam and a few in the capital area. Shoe Repair. Makers of shoes are shoemakers or cordwainers. 

[deboardp]

6 hours ago, Wepster said:

There are probably a hundred cobblers in New York State alone (one source states 7000 in the US). There is one in Amsterdam and a few in the capital area. Shoe Repair. Makers of shoes are shoemakers or cordwainers. 

Sheesh... I guess I shoulda run a search for cobblers near me. It's probably a good idea to visit one, or call first, ask if he would be willing to show me what he uses for sole rubber.

Cordwainer???

Edited January 28 by deboardp

[deboardp]

On 1/25/2024 at 12:05 PM, Mablung said:

Wow, that's thick.  Apprise us of how it feels on the foot. 

It is thick. but not as thick as what I made 50 years ago. I don't remember exactly what I bought, but I know the bottom was bend, and it was thicker than the top, which I have no idea what it might have been. A snatch-out-of-the-air-guess would be 12 ounce shoulder for the top and 14 ounce bend for the bottom, and 7/8 ounce horse hide for the straps. 12 and 14 is 26 ounces total. This current sandal is 10 ounce shoulder and 15.5 ounces of veg tan for straps and lower soles, for a total of 25.5 ounces. Because the sandal is so stiff - and that's without the rubber and heel - I will keep the shoulder for the top and move to two layers of 6 ounce luxury veg tan for the straps and two lower soles, for a total of 22 ounces total, or 3/8" (rather than existing 7/16"). It's not much thinner, but two lower soles are luxury veg tan, a supple leather, as opposed the Hermann Oak craftsman veg tan, which is firm. It might make the sandal more supple and less stiff.  I guess we shall find out!  

I'm keeping the top at 10 oz because when I tug on the strap to tighten the front strap, I don't want the topsole to bulge away from the midsole. I want it to be the most durable sole. The mid-, bottom- and gum-soles will add plenty of stiffness, putting the overall thickness at exactly 1/2".

[Tastech]

Deboardp. Here is a link to the material i would recommend. Its a consistent thickness material called microcell. It is soft, flexible , easy to cut and glue and is relatively tough. It comes in multiple colours , multiple thicknesses and multiple tread patterns . Not that expensive either  

 https://www.leffler.com.au/shop/shoecare-repair-orthopaedic/shoe-bag-repair/rubber-heeling-soling/rubber-soling-sheets/

 You must have a shoe repair cobbler close by . They don't have to be high end , Even a retarded one will be able to show you some options .  Cobblers are notoriously cranky buggers  so go in there on the premise of getting some soles on sandals ,but you want to think about options . They will show you some different types . Make sure you feel them to gauge the material for softness . 

Below is a vibram tapered sole with the heel ready to go .(recommended)

The other photo is various microcell .

Your options are too numerous to list or show . Its all about what you want the sandals to look and feel like . You can also incorporate a layer of cork below the top layer which over time will mold to the contours of the wearers feet . All decent shoes have a cork layer under the innersole . If you want a seperate heel cut one out and glue it on top of the sole .

Your sandals should be thus . leather upper sole (innersole ) ,cork midsole , And rubber or microcell or EVA bottom sole . Don't over do the leather thickness as this makes them to hard and uncomfortable .

Go to a few shops and study the anatomy of a sandal all are different but you will see some thing you like and you can incorporate that feature in your design .

https://www.ancient-greek-sandals.com/en/eur/mens-sandals

Note the different soles on some of these sandals . Only women can wear flat plain leather sandals , Men need some contour and some taper. Be prepared to experiment , and don't be discouraged by failures .You learn valuable lessons . The greatest glory in living is not never falling ,but rising when we fall .

Sorry for my long winded answers but i don't do things half assed . Balls deep or nothing .  

 

[deboardp]

7 hours ago, Tastech said:

Here is a link to the material i would recommend. Its a consistent thickness material called microcell. It is soft, flexible , easy to cut and glue and is relatively tough. It comes in multiple colours , multiple thicknesses and multiple tread patterns . Not that expensive either  

thank you! You've opened up a new world for me, the world of rubber soles. I'll work in a visit to a cobbler soon. apparently there's a hundred of them within an hour of my apartment. 

7 hours ago, Tastech said:

Go to a few shops and study the anatomy of a sandal all are different but you will see some thing you like and you can incorporate that feature in your design .

I studied sandals 50 years ago, and then again this past year and a half, and I haven't changed my mind about sandals. Both times, I came up with the same conclusions, which are that 1) sandals made by a size pattern ignore the specific skeletal architecture of the individual, instead opting for a one pattern fits all. Usually this pattern of straps results in the toes being pinched together, and general discomfort if not pain, that does not stop after the sandal is broken in.  Also almost all straps made in a commercial sandal are non-adjustable. If the straps are made of leather, the leather will stretch out and the sandal will fit poorly. Because of this, I resolved 50 years ago, and maintain this resolve today, to only make custom sandals. The major bones have to be marked on the foot tracing, which are the big ball, the little ball, and both inner and outer ankle bones. The straps need to encompass both balls in front, and be below both ankle bones in the back. That's for my design, which has nothing between the toes and is created so that the wearer can wear socks. I also resolved that every strap has to be 100% adjustable by the wearer, to either loosen or tighten each strap.  When I look at commercial sandals, I usually shudder at the thought of buying and wearing such a cheap, ill-fitting piece of junk. It's a little like being robbed, actually. I looked at the link you sent, to the Greek sandals. Sheesh, what a waste of effort to build those things! If there wasn't the Mediterranean Sea right there, and the sun shining, nobody would buy those things. And the prices! Wow. So high!

I won't change my design until I've worn this first pair and get some real feedback to my feet. While wearing them I'll make the second pair with thinner mid- and bottom-soles. Hopefully I'll find a microcell that will satisfy me. I'll try what I have on hand first, despite not knowing exactly what it is, except that it's pure gum rubber. I'll use the heels I have, too, just to see if they work. 

the cork is a good idea. I'll think about if I can incorporate it. I want my sandals to last a couple or three decades, and the cork might not be appropriate.

Edited January 29 by deboardp