Last making Method
I have designed a new system/method for making lasts which is particularly suited to the amateur shoe maker/industrial designer and is highly environmentally friendly and completely cradle to cradle in its approach.
Before i start with the steps there are some things to clear up:
plasticine: What i refer to as plasticine is more correctly referred to as oil clay. It is a clay powder based sculpting medium which unlike clay and water, never sets or dries and never shrinks. If you want this method to be totally cradle to cradle then get your hands on some totally natural plasticine or make your own: clay powder, castor oil and bees wax will do it.
Papier-mâché: This is paper and glue made from flour and water. All you need to do is mix up flour and water to a paste consistency. And get strips of porous paper - news paper works best and you wet each layer of paper with glue as you apply it. Its versatile, natural and safe and easy to work with. And it can make some seriously strong structures if you layer it up carefully and keep water off it.
Step 1: Get a piece of card board, i use pattern making card, as i have lots of it. put your foot on it and trace out the shape of your foot. Mark around the tracing with the shape of the sol of the last/shoe that you want to make. This is a lil bigger than the shape of your foot - especially at the toe you need to add about 8mm. Mark the joint and the instep. You will need to get a shoe pattern making book to know exactly what I'm talking about here.
Step 2: Punch holes in the card board at the edge of the last shape where the joint and the in step marks are. thread string through the holes. Put your foot back on the card board and measure around your foot with the strings and mark them or cut them to show the measurements. These strings will be your main guides when shaping the plasticine last, they will tell you what the girth of the last should be at those two points. A heel measurement should also be taken as a third measurement for the last. You can take more measurements and put more strings in as you like.
Step 3: Put plasticine on the cardboard and build up and shape the last. You can keep checking your measurements as you go using the strings etc... Also once you have a shape that your starting to be happy with, you need to add some "toe spring" and/or "heel spring" unless you want a flat soled shoe. This means to curve the toe area of the shoe up, I usually do this once you have cut off the excess card board, flush with the Plasticine last edge. This last edge should be sharp for a glue lasted construction shoe and rounded for an out stitch construction shoe.
Step 4:Once the last shaping is finished and you are happy with it you can use thread/string and press it into the Plasticine to design the upper pattern/ where the seam and other upper features will go.
Step 5: The last is then covered in a thin layer of Papier-mâché.
Step 6: Then cut the last into three pieces, by taking a wedge out of it at the opening of the shoe. This creates a wedge that can be removed from the last, to make it easier to remove the last once the shoe is finished.
Step 7: All three pieces of the last are then covered in a thick layer of Papier-mâché.
If you are going to heat the last at all then you will need to do just a thin layer of Papier-mâché at this point followed by a layer of shellac, followed by a thick layer of Papier-mâché. This layer of shellac stops heat from letting the oils in the plasticine/oil clay from being drawn up by the Papier-mâché, and making it soggy.
Step 8: Once the Papier-mâché is dry you can use just a few pieces of Papier-mâché to join the three parts of the last back together.
Here we can see the wedge that has been lightly Papier-mâchéd back into place.
Step 9: You can then remark the upper pattern and other details with a pencil/pen, these should be able to be traced off from the string which is under the Papier-mâché - not easy but it can be done, or you could just draw them on again, from photos/memory.
Step 10: (optional) if you want the last to be water proof then you paint the whole thing in shellac. Note: Shellac is both oil and water proof, it's solvent is ethanol, i use white spirit a.k.a. metho.
The finished lasts:
Clearly this process is a long one, but it permits some exceptional results in last/shoe design without the need to go and learn the skills required to wood carve lasts, or drive a 3D modeling program to get the lasts 3d Printed... Plasticine is very forgiving and great to work with.
© 2009 quentin Irvine