Limitations of Last Modifications

[AdamGadut]

Truely Shoe lasts are very very rare to find. i found a couple stores locally that sells them. One of the stores sells only in dozens and for female foot - with varied sizes. Luckily the other store sells individual pairs for men sizes, BUT, my foot is size 9&1/2 and the last few ones they have are size 8&1/2 and size 8.... 
Having seen some youtube videos of cordwainers modifying their last shapes by adding cork boards, I went and bought the size 8&1/2 and some cork boards... 

i havent fully done the modification, but still is about half way and i've added about 3 layers of cork on the outer side. - My feet are fairly wide. As i see the lasts, they still need about a layer of cork more on the inner side... 

So my question is... Is there a limitation to this modification?.. is 3 layers of cork on one side ok?... 

seeking the wisdom of those who have done this.

[Saturn]

build up with leather or bondo type auto body filler.

or

buy larger and carve to suit.

 

I have no experience with cork in this application, good luck

 

[AdamGadut]

Saturn, now that you mentioned autobody filler, i will coat the cork layers i already laid out to reinforce them... thinking about this question now, I imagine the filler material had to be stiff enough to withstand a razor sharp blade for the patterns. thanks a lot

[electrathon]

Body filler is at best a bad choice.  It will not handle the stress of lasting.  leather is a better choice, it may be glued on and will not crack and flake.

Changing the size of a last can be tricky.  You need to measure in multiple directions.  Length, width, girth, etc. are all involved.  Changing one measurement can alter another.  You need to find lasts that are almost correct and then alter from there.  Last making is actually pretty advanced, sort of like collage level shoemaking.

[AdamGadut]

Thanks Electrathon, i will use leather instead. 

I agree with you about the difficulty in the last. Me making it match my foot has been quiet challenging. I keep trying to compare it side by side with my foot on every change i make, also comparing it on the sketches of my foot's shape. 

[RockyAussie]

5 hours ago, AdamGadut said:

Saturn, now that you mentioned autobody filler, i will coat the cork layers i already laid out to reinforce them... thinking about this question now, I imagine the filler material had to be stiff enough to withstand a razor sharp blade for the patterns. thanks a lot

As Electrathon says a build up with leather is the way I would recommend. A few slice marks in it from patterning will not effect the lasted result and won't hurt your cutting knife either. I have not ever used cork board for building up with and I doubt I can see much of a reason why. With leather you can get it take up and go around the compound curves fairly easily and sand or skive down to the required size. The whole lot can be peeled of normally if you want to go back for another job. In the past I found difficulty getting B size lasts and in the hot Queensland weather and the open style footwear normally worn the average feet here tend to be broader across the metatarsal area. That is the wider part of the foot before the toes. I overcame this by doing a 3mm moulded poly type board cast over this area and sanded down into shape and this then allowed me to clip it on or off for whatever size needed A or B in this area of foot. As to how much in size you can build up it is only relevant to the feet in question and the desired shape you want.You'd be surprised at some of the shapes you get when doing surgical shoes after a while.  Regards Brian

[electrathon]

A last is not the shape of a foot.  Some bones need compression and support and some need space to float.  Few lasts are foot shaped (think clunky orthopedic shoes for foot shaped lasts).  The top of the last is never foot shaped, that has to do with removing the last from the shoe.

I would recommend that you do reading online on measuring of the foot, that will help, but does not address many of the reasons why lasts are shaped like they are.

[RockyAussie]

21 minutes ago, AdamGadut said:

Thanks Electrathon, i will use leather instead. 

I agree with you about the difficulty in the last. Me making it match my foot has been quiet challenging. I keep trying to compare it side by side with my foot on every change i make, also comparing it on the sketches of my foot's shape. 

Are you wanting to make closed in footwear? Can you post a picture of the last side on and down from on top and bottom?

[AdamGadut]

Yes a closed footwear. I will post later as soon as i get photos of the last. 

the areas of the last i have been building up material are on the outer sides and the toes - maintaining that rounded Toe shape for the shoe, and on the heel, extending its length. 

[RockyAussie]

3 minutes ago, AdamGadut said:

Yes a closed footwear. I will post later as soon as i get photos of the last. 

the areas of the last i have been building up material are on the outer sides and the toes - maintaining that rounded Toe shape for the shoe, and on the heel, extending its length. 

I will check back for the pictures a little later and let you know what I think best.It may be best to show an outline of your foot and whatever measuring procedures you have done.Brian