Friday, 7 April 2017

Ruff guide: Making a mold from a dolls leg

How to make dolls shoe lasts - part 1.


You know how one minute you're saying to your bestie..  "I'd love to make dolls shoes, but I need some lasts, making shoes on the doll is so cumbersome"  .. and the next minute you're up to your elbows in silicone rubber?

Okay.  So it's just me then.

I did in fact chat to bestie about this, explaining that 'lasts' were items used by shoemakers to form the shoes. And were sort of like feet in shape, to make things easier all round.   And ended up buying some silicone moulding rubber, and catalyst, and some plaster of Paris to make the lasts.   I've some experience of mould making from my jewellery business way back when, and I thought how hard can it be?

Not hard at all, as it turns out.  With minimum equipment, I managed to make the mould.

So here's what I used:

Silicon moulding rubber with catalyst. (Shore A28 or thereabouts, which is the grade of softness. Mine is medium soft. Shore A27 to A30 would be fine)  Here's the exact stuff I used: 

Greyboard (3mm thick)
Duck tape. (aka duct tape, gaffa tape, elephant tape)
Clingfilm (saran wrap)
Masking tape
Bits of stretchy cloth, and some for padding, depending on your support for the doll.
My desk lamp (support for doll)
The dolly
Scalpel with a brand new sharp blade.
Mixing spoon.

All this stuff can be found on Ebay, using the names given as the search.  I get asked where I get all my supplies, and I always say Ebay.  I'm agoraphobic, so almost all my stuff is bought online. (Apart from the spoon which was filched from the kitchen drawer.)

Also - do not freak at the thought of cutting rubber away from your precious dolly with a REALLY sharp blade.  I do understand, and I agonised about doing it for a couple of days.  BUT, the nature of the rubber makes this easier than you may think, and we do protect the doll's legs with clingfilm and masking tape.

So, on with the project.

First, protect your very expensive doll!  I'm using my Kaye Wiggs Layla, so I've been incredibly careful with the body.   Wrap the legs in clingfilm first, and then masking tape.  This not only protects the resin (you will be cutting with a sharp knife later) but it holds the foot still and in the right position.

Casting a dolls leg


The doll needs to be suspended so the foot is not resting on the bottom of the mould casing.  I've suspended mine from the hook on the neck by tying it to the upright of my desk lamp with soft strips of cloth. I've padded her back and tied the body at the waist.  Protecting your doll is actually more important than anything else.  You can make another mould if this goes wrong, but buying a new doll might not be possible if it's a rare lilac resin.

My doll's foot was about 1/4" (6.25mm) from the bottom of the mould casing.

Casting a dolls leg

I made the mould casings out of the greyboard, leaving space around the dolls foot for the walls of the mould.  Duck tape is awesome.  Have some. Love it. Cherish it. With it, you can take over the world.  My mould casings are 13cm tall x 7.5cm deep x 5cm wide.

Make sure your card mould casings are fully sealed at all edges with tape.  And I added a blob of blu-tack  into the inside corners of the boxes, to ensure there were no leakages.  Cardboard is fine to pour silicone into, but it needs to be stout and well taped.

The silicone rubber comes in a tub, with a separate bottle of just enough catalyst for the whole tub.  My tub was 500 grams. I just added all my catalyst and stirred well with a spoon.

making mould for dolls leg

The 500 grams of silicone was enough for only one leg.  Bah. I've ordered some more though.  It was serendipitous actually.  I was going to try and be clever and do both legs at once, but no.  Do one at a time, as it would be too awkward to cut off the rubber once cured.

I got some silicone on my doll's bare leg, but that was okay. It peeled off easily once cured.

The silicone is meant to cure in about 3-7 hours.  Rubbish.  Mine took 24 hours, so don't panic if it's still soft and goopy after 7 hours.  Leave it overnight, resist the urge to poke it to see how it's doing, and it should be a nice cured block by morning.

I laid my doll down carefully to cut off the mould.

making mould for dolls leg


I found the duck tape easy to peel off the greyboard.  Keep your box intact if you can, it will be good to use foot holding the mould parts together later, when you cast your last.  (ha.)


making mould for dolls leg


It's always fun to see the solidified rubber as you peel off the card.

making mould for dolls leg


Here's my box, pretty intact and re-usable.



Before I say anything else, I shall say this:  When you cut your rubber mould, cut a jagged line. NOT a perfectly straight one.  That way the two halves will be easy to put together exactly right.

Instead of cutting down the centre of the fronts and back of the mould, I cut mine at the sides, because that mass of rubber at the front is a bit much to cut with a scalpel.  It cut beautifully, I must say.  Like butter.

Now, I've already put masking tape on the doll's foot, to protect from the blade, but the rubber is soft enough that if you cut your (jagged) line without touching the doll's leg, you can hold the rubber apart, and just a gentle touch of your beautifully sharp and brand new blade will cut away the inner part.


Using silicone rubber for doll shoes


The red arrow shows the part where you can stroke the blade gently.  the rubber is also soft enough that you can pull it slightly away from the doll's leg.  My blade never touched the masking tape.


Using silicone rubber for doll shoes

Below, I'm cutting the other side:

casting a dolls leg


Again, the arrow shows the inner part of the rubber, where you can gently stroke the blade and slice it open.


casting a dolls leg


Et voila!  My two-part mould removed from the doll.  You'll need to tug a bit to get the front of the dolls foot out, but the rubber is soft and very strong.  Just go gently, but firmly.

making a mould from a doll's leg


I've always enjoyed mould-making, but never really find anything I want to cast.  Shoemaker's lasts are ideal for this fun project.

Here's my mould put together.  See that jagged line I cut? that's what makes it easy and acts as a 'register' for the two pieces to fit together easily.  A straight line doesn't work very well, the two pieces won't anchor together.


making a mould from a doll's leg


Some people hold their two part moulds together with tape, or elastic bands, but as the rubber is quite soft and might distort, you can just tape your original box around it to hold the two parts together.


making a mould from a doll's leg



Next, I need to do the other leg, and I'll try to publish my progress when I actually come to casting the plaster in the new moulds.

None of this means I will be making perfect little doll shoes. I'll be attempting it, of course, but for those of you who want to cast any doll's feet/legs for making lasts, this should be of some help.


PART 2 Here:

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4 comments :

  1. Fascinating..... but I think I'll stick to the sewing, knitting and crochet! Looking forward to seeing how it all turns out!

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    1. Ha, yeah I figured it's not everyone's bag, but I'm like a mad scientist, I like to experiment and document my findings. I'm hoping I can make some decent shoes after all this!

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  2. Oh how fascinating! I'm not sure I would have your patience though, I'm notorious for poking things that are drying or setting!

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    1. I can't tell you how many times I poked and prodded it. :p I'm such a hypocrite. Hee.

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