Day six was the final day, and it was mostly about attaching the sole to the shoe. In this case this was to be a glueing job, with the odd nail thrown in for good measure.
Glue is one of those technologies that has improved over the years to the point where its a very reliable way of fixing things together; but, it still requires suitable preparation of the surfaces, and good handling procedures to work properly. The lasting process had meant the day started with the upper still on the last, and glued onto a inner sole.
The upper on my shoe is a chunky leather, and that combined with the inner meant that there was quite a high ridge of material sitting above the plane of the inner. For glueing purposes we want a single flat surface to attach the sole to. But you can’t just grind the whole surface flat; that would take away layers of leather to the point where you might not have something with any thickness left to hold onto the sole.
The solution is to fill in the space a bit with some “filler,” and a bit more “skiving;” removing the ridges and bumps of material. Tools used were a knife, but also the sanding wheel for speed.
As to the filler, this is a sole of a shoe, so it needs to have the characteristics of being light, flexible, and tough, but some of it also really needs to be a putty like substance one can work in to the gaps. It also need to adhere to the insole and the sole proper. The filler in this instance was cork putty, that was suspended in a glue mixture. Sue also mentioned that she had created her own filler using the sandings and scrapings from the workshop mixed with a glue, and that you can also use felt. I’ve also seen cork sheets used in a video which then presumably had filler around it. Whatever you use, you don’t really want it to contract too much as it dries either, so along with all the other needed properties, the glue needed to be stable, and packed out enough with fibres and particles that contraction isn’t an issue. My suspicion is that originally you could use fibres etc, that were then glued, and pre-mixed fillers were a in-house product. Whatever the history, there were some interesting shop floor materials science going on in the history of shoemaking.
With the filler in place, skiving and sanding can begin to get the bottom surface to a point where it can take the glue and the sole. The sole was prepared too. It needs to sit on against the upper in such a way that it doesn’t rock or move once weight is applied to it. Even with the best glue in the world, if the sole and the shoe were not married together in a way that was even, the working of the shoe while walking would put a lot of pressure on the glue. What’s more, one end of the surface is going to have a heel under it. So its not just a matter of slapping the two surfaces together: there is a bit of fine tuning and shaping of the sole surface, as well as the upper surface, prior to glueing.
The sole also needed to be fine tuned to fit well under the upper, and to make sense of the design. So this was trimmed and shaped a little prior to gluing.
Gluing with contact glue is always slightly nerve wracking. While contact adhesives can take a little bit of re-positioning if only small parts of the surface are in contact, mostly its all over once they touch; thats where they will stay unless you want to compromise the adhesive. So there is a bit of eyeing up, positioning, and thinking through the best way to bring the two pieces together. For all the glueing involving contact adhesive —the heels, sole layers etc— this is a process of either building in margins of error that can be trimmed or ground off later, or just working hard to get it right the first time. I confess to sort of messing up one of my moments of glueing, placing the soles rear edge too close to the seat of the heel, and as a consequence, to much sole poking out the front. This is a bit of a disaster visually, as if there is any part of a pair of shoes that gets seen at the same time and at a angle to judge difference between the two shoes, it is the toes. Particularly from above.
Once in place, there is lots of whacking, thumping, and squishing to ensure that the two parts of the shoe on in good contact with each other. As usual with these procedures starting in the middle, and moving out to the edge, hopefully removing air bubbles, excess glue, and not creating creases. I found myself happily using my body weight against the door jamb, pressing the sole into place.
Once this was done, and the soles glued, it was time for attaching the heels. These were glued, but were also nailed. Many of Sue’s lasts have a metal plate in the back portion around the heel area. If you nail through the leather, rubber etc, the nails should hit that metal plate, fold over, and then lock themselves into position like rivets or staples. Apparently some traditional shoe making used wooden pegs to do something similar. I can picture this if you shape the end on your peg suitably it should spread once it hits something suitably hard. A touch of glue at that point and the result would be a bond that was quite strong.
Then the lasts are removed. This can be a tricky process, but in my case it was straightforward. A last that bends in the middle like a foot helps.
Once in place, and off the last, the heels and soles need some finishing. Traditional this would involve the shaving of the heels with the sharp edge of a piece of glass; in effect placing the leather soles. This would also happen on the sole of the shoe, removing the glossy bit. Much of that process can now be done with a machine, sanding and buffing, but some of it I did by hand. Finally, the edges of the leather soles were burnished with a hot iron. This melts any wax in the leather, but also helps the fibres lie down, and stay smooth and flat.
These finishing processes can take a while, and can be indulged in to extremes. Indeed, for really expensive shoes, this attention to details is probably what you are paying for. We were a bit rushed on my final day (I had to catch a ferry, a shuttle bus, an airport bus, and a plane to get home) so we didn’t indulge too much. I could have faffed around for a while.
Perhaps the only really disappointing thing was that I couldn’t wear the shoes out of the workshop. They needed time to dry, and time for the glue to cure properly, so into a bag they went, carried on the journey home.
I did stick them on my feet though.
I will reflect on the whole process, and the result, in another post. But I am pleased with the shoes. I will wear them. They won’t sit in the cupboard as a trophy. There are things about the design and some choices I might do differently, but that is purely hindsight. I made the right choices based on the knowledge I had, and the things I wanted to try.
So the next phase is wearing the things.