Casting for lasts

Box for foot mold

I’ve finally got all my ducks in a row and have cast one of my feet in pursuit of lasts for making my own shoes.

I zipped together a box for the mold, using scrap pieces of 6″ plastic pipe to fill in corners so I don’t waste molding material.  I sealed the seams with some caulk I had on hand (butyl silicone).  I think just about anything would work as a sealer.  One pound of alginate fills the mold to my ankle.  How great is that?!

Foot impression filled with plaster

I taped my anti-arch support in the bottom of the mold before adding the alginate, then stood in the alginate until it set up.  Getting my foot out was pretty easy, just a little wiggling and I was free.

It takes 4 cups of plaster of Paris to fill the mold to the ankle.

The alginate is a nice molding medium.  It’s pretty easy to tear apart to remove the plaster of Paris positive and it faithfully reproduces whatever is molded.

Lorr, cleaning up the positive

I went up to our son’s to get a part for my table saw repaired.  While I was there he cleaned up the positive, a necessary step in getting it ready to mold.

The final shape, just needs a final clean-up and smoothing

And there you have it, a semi-ready form to cast for my left foot last.  I still need to skim-coat it with Bondo before a final sand to make sure it’s smooth, smooth, smooth.  I’ll get the right foot done this week.  Hopefully we can get the lasts cast this coming weekend.

Making shoes will be a good bad-weather project.  I really need shoes that will support my rotten ankle and keep my feet dry while running around outside.

12 thoughts on “Casting for lasts

  1. I just happen to come across your blog as I was searching on how to make my own last. I’ve tried the duct tape version and after I stuffed it, it was too thick. Plus it’s hard to do it on your own foot so I need to redo one of them.

    I just wanted to know if you used your duct tape last and were able to make a decent pair of shoes?

    The plaster looks like that might be the way to go.

    Thanks for sharing. I found your blog interesting.

    1. I have a successful mold/last system . . . I think! See if you dentist will sell you some alginate. I have the world’s best dentist and staff, so when I ran out of my initial Ebay purchase (2 lbs), they ordered three more pounds (one pound per casting). If your dentist isn’t as awesome as mine, you can buy one pound bags of alginate on Ebay.

      Build a mold for your foot. I used 2×4 and plywood, filling in the corners with something to avoid wasting alginate. If you can only make a box and can’t fill in the corners, you’re going to need more alginate per foot molded.

      Mix the alginate 2 parts alginate to 1 part COLD water. Stir 45 seconds (I used a beater from my electric mixer, mixing it by hand) and pour into the mold. Step in, stand firmly on the foot and don’t move until the alginate hardens. It will be cold, it will be uncomfortable, but don’t move.

      Once the alginate sets you can wiggle your foot and ease it out of the mold. Mix enough plaster to fill the mold. Pour some in and turn the mold toe down and bump it a couple times to get the air out. Set it back down and fill to the top of the mold.

      Once the plaster has set (I left mine for a couple hours ’cause I was busy), tear the alginate apart and take your perfectly molded foot out. At this point, you’re halfway there.

      Mix some more plaster (1/2 a cup?) and build up the toe to suit you. If you set the plaster foot on a piece of plastic film (Saran Wrap, Glad Cling, etc.) while you’re doing the build-up you can use the plastic to push the plaster around and hold it in place.

      Set the plaster foot aside and let it dry (days). Sit it where warm air blows across it to speed drying. The dryer it is, the easier it is to smooth and shape. Once you have it shaped. smooth and dry, oil it really well.

      From here on out, we’re talking speculation based on experience. I am not to the point yet where I can do these next step. Maybe next week. I’m doing reconstruction (moving the laundry room and rerouting water, gas and power) so haven’t got the time to spend on it right now.

      The next step is to make a negative mold from the positive (plaster foot). There are a couple ways to do this and I’ll have to play a bit to find the best method. Keep on eye on the site. I’ll post it when I figure it out. Once I have a negative mold, I’ll use it to make a last using a 2 part resin that mimics wood.

  2. I’m very interested in making shoe lasts as well, except for high-heels. How would I go about doing this.. Could I cast my actual shoe or just wear heels while casting my foot?
    I’m going to try the alginate to make a negative and plaster of paris method to make a positive, although plaster of paris is not the best material for lasts since it chips.. I’m very interested in the 2 part resin that mimics wood method, wondering what will be used for the negative mold.
    Thanks for posting!

    1. There is a very good book on casting your feet for heels by Mary Wales Loomis called Make your own Shoes. She pulls the heels off old shoes and stands on those while casting her feet. She has a nice detail on how to build the shoes, so for you, her book would be worth the $25.

  3. I think I’ve come across her website before.
    Have you tried the 2 part resin last? I’m very curious,
    Since the best lasts are from wood or cast iron because you can use nails and tacks, could you use nails and tacks on the resin?
    I’m from washington and they have a few shoe schools and casting schools here, but unfortunately they are thousands and it’s pretty difficult to find straight up information on the web. I’m sure some books would be a good investment. Thanks for the feedback.

    1. I’m in Washington as well. I’m down by Chehalis/Centralia. I, too, don’t have that kind of money to spend.

      I haven’t tried the two part resin yet. I’ll post when I have tried it. I still need to clean up the second casting and get both castings coated in bondo and sanded smooth. From what I’ve seen of the cast resin, it should be perfect, resilient and strong, accepting of tacks.

  4. Sounds good, i’ll sign up and stick around, i’m looking forward to seeing how it goes over. Have you figured out what your using for the negative to cast the resin?
    I’ve been reading over Mary Wales Loomis website and she does have some great information. I’m looking forward to making my lasts since constructing the shoes is going to be the hard part. My aunt is a dental assistant so I, too, can get alginate relatively easily, i’m hopefully going to get 4-5 pounds to start. I’m going to make my first lasts in a pair of 4 in. heeled boots and pour the plaster of paris directly in and cut the boot away after it dries. Then I’m going to prepare a box and use the heel from the boot to stand on to make a 4 in. regular mold of my foot with the alginate for the negative and plaster of paris for the positive. Then I will do a regular flat foot cast of my feet with the alginate and plater of paris. Do you think I’ll have enough alginate for the two sets?
    I’m going to do 3 sets to start with, how far does the plaster of paris go? how much did you buy/use? What grit sandpaper did you use to clean up your lasts?

    1. For heels, you’re going to use a lot more alginate for the mold, just bear that in mind. If you can get some modeling clay, you can fill in front of the heel to take the place of the alginate. You can tell how much alginate you’ll need by pouring warm water over your foot in the mold until you get to the level you need for your mold.

  5. I have a size 5 women’s foot with a high forward arch, as one can imagine I cant find any shoes to properly fit and as of recent it has started taking a toll on my lower back. Last year because I cant find any well fitting shoes I ended up with 19 stitches in my right foot because I was wearing flip flops instead of appropriate foot wear. Does anyone have any suggestions as to where I can get nice looking shoes made to a mold of my foot for a decent price, I dont think anyone knows how badly as a woman I want heels. Please help.

    1. It’s the “reasonable price” thing that’s going to bite you. Because of the many hours it takes to make a custom last and construct the footwear, it’s not inexpensive, and anyone worth their salt is going to make a fitter to ensure the shoe is going to fit correctly before making the actual footwear. That alone adds to the price. The best fitting shoes I’ve had made by others were the ugliest things you’ve ever seen and they cost me $650 a pair nearly 10 years ago. Now, a pair of custom shoes is going to run you twice that amount.

      There are some things you can do to make yourself footwear that’s fairly easy and inexpensive to make. Let me give you a few ideas and save you the time reading through everything on my site.

      Check out Island Sandals. They have a website with embedded video showing the sandals being made. You can order a pair or make them yourself. There’s a pattern for this exact sandal on the internet but you’ll have to look for it (or ask me and I’ll dig mine out if I can find it). The upper is done with long strips of leather you can buy precut. I think I got mine on eBay. You’ll need enough 6-8oz leather for 6 of your footprints and one set needs to be the same thickness as the straps. If you want to go this route, let me know and I’ll walk you through it. It’s an afternoon project once you have all the tools and supplies.

      If you want a shoe with full coverage you can accomplish this with fairly simple stitch down construction in a couple days, not because it takes that long but because the leather has to soak for a while before you can shape it over your foot. There’s a book you can buy which goes through the process (The Make-It-Yourself Shoe Book by Christine Lewis Clark) but be prepared for a bit of a learning curve as the book doesn’t cover everything you need to know.

      If you want to make your own heels, there’s a book by Mary Wales Loomis which takes you through making your own shoes. The caveat with this book is you need reasonably good fitting shoes to start with.

      I hope all this helps give you direction and ideas.

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