Tuesday, 8 March 2011

Prototyping a New Mould - I Trashed MY Kitchen (so you don't have to !)

Forgive me - I started this post about 3 weeks ago. I'm going to add the photos and finally post it - adding what I can along the way.

I hope you enjoy my post about prototyping !

Oh the mess.... My kitchen has been like a bomb site for the last few days. It still is - and I need to tidy up before bed !

I've been trying to complete a project to make a new prototype mould for the last week and it has not been an easy task.

I've wrecked : 2 x wooden spoons, a plastic bucket, a measuring jug, countless dish cloths, 2 paint brushes, a pastry brush, a really nice fleece jacket, a pair of jeans, 4 pencils, a big glass kilner jar

I've used : bucketloads of buttercream icing, a litre of liquid latex, loads of poly bags and cardboard boxes, 8kg plaster of paris, 1kg dental alginate, 1kg silicone rtv compound, 3kg soap, a full bottle of fairy liquid, all 3 tubs of Oliver's Playdoh (ssssh - he doesn't know yet !), 2 x tupperware boxes, stacks of tin foil and grease proof paper, a load of melt and pour soap base, countless disposable piping bags, a stack of paper cupcake cases. What's more - that's only what I can remember off the top of my head !

I've been on the verge of tears with frustration and then almost swinging from the lights with the excitement of success.....before crashing back to earth with set backs.

Why you ask ? All because so many people keep pleading with me to make a special mould for making cupcake lookalike soaps, candles and bath bombs....

I've tried every method I could think of to recreate a buttercream iced cupcake in a moulds form. Thing is - how can anything look like a buttercream iced cupcake if it is NOT a buttercream iced cupcake ?

I wasn't crazy enough to take photos of the disaster zone in my kitchen and I was not insane enough to photograph my horrific failures either. Those made their way at warp speed into the bin.

What did sort of work was piping buttercream onto the top of wafer cones stuffed full of old bread and then chopping off the tops and putting them on top of a silicone baking sheet. I then put playdoh all round the bases and painted on about 20 layers of latex one at a time waiting until each layer dried before repeat coating. A proceedure that took days...

Once they were ready, I peeled them off of the silicone sheet and put them into a little cardboard box lined with plastic. The mouldy buttercream / playdoh mix was still inside at this point.

On top of this, I then poured plaster of paris to create a negative support for the final latex moulds. There were about 6 of these latex attempts in total and in two different sizes.. After separating the latex from the plaster of paris, I think tried to degunge them of buttercream and playdoh. This partially worked as the layer of latex in contact with the buttercream never did actually dry..

This meant that when I eventually cast into the latex moulds with melt and pour soap, much of the internal layers of gungy latex actually stuck to the soap. Several hours of paring the old latex out of the positive soap casting then followed. I think I got between two and three attempts at casting from each latex mould before they completely disintigrated

These are the corrected "positive" soaps to be used to recast from.

I then used liquid silicone to create a better negative cast. I had disasters with those to a certain extent. Once the liquid silicone was poured over the soaps, the soaps dislodged from their playdoh anchors and floated to the top ! I had no alternative but to flip them upside down and hope that my mother mould would turn out ok ...

Let me tell you. It's nigh on impossible to wash off liquid 2 part epoxy silicone. You shouldn't touch it with your hands - but I had hands covered in it, some on kitchen work tops and on the floor by the time I was finished that night.

At the same time as building up latex layers over buttercream, my other idea was just to make some original full cupcakes from plaster of paris by pouring the base parts first into a silicone muffin tray and then icing the tops on. The bases worked ok - but did not look realistic without the paper creases. I cast some into paper cases in the mould and then spent forever trying to get the paper off the plaster casts.

Once I had a stack of bases to work with, I had a go at creating the tops.

I think my nightmares are made of plaster of paris.

It's damn awful stuff to pipe. Trying to pipe it was not such a smart idea !

3am in the morning and I'm stood in the kitchen mixing plaster. The bag reckoned 40 mins to set. What I did not allow for was the fact that I needed only a fraction of the amount of water to make it to the same consistency as buttercream. I quickly loaded the buttercream plaster into my piping bag.


Blooming stuff was rock solid ! I'd made enough to do a couple of bag loads. It was stuck solid into the bucket. My wooden spoon was welded to the kitchen sink. I panicked incase I was going to have blocked the kitchen sink, having rinsed a load of stuff down there already. In the process, I got plaster residue everywhere ... floor, door handles, me, kitchen surfaces. I broke the bucket. The spoon was not salvagable.

Batch two was a little better. I only made up enough to ice 1 > 2 cupcakes. I got one good one, and one 1/2 iced before it went solid.

That night, I didn't go to bed. SIXTY go's and the result ? Only one usuable item. Guess what - it was the one I made on the first attempt !

I don't have a photo of any of the plaster cast ones on my camera. Lucky me :-)

Anyway, from the one good one, I used liquid silicone to make a trial negative mother mould. This is it pictured above. I had nothin left to pour the silicone into, so preped the plaster positive cast into an empty Kilkner jar. Once this had set, I smashed the jar to get the mould out.

Next was to cast into this. That was ok - the only problem was that the mould was so thick, that I couldn't get the casting out ! A very very sharp knife, 45 mins, a couple of plasters and a bloody finger / kitchen floor later, I managed to get the cast out.

Unfortunately, when triming down the mother mould - I cut in too deep and made a little hole in it which went unseen at first. That meant that my next attempt at casting after a few little ammendments didn't go to plan and hot wax was streaming everywhere.

Hmm. Duct tape. Fantastic stuff. Several meters of that to bodge with meant I could cast into the mother mould and create a decent sample AND get the sample out.

The candle shown above was my first successful attempt at casting into the large mother mould with wax. I broke the candle in a few places trying to release it before I chopped the mother mould about and created carnage on my hand. Subsequent casts came out perfect and once happy with it, I sent a positive and negative mould / cast away to try and have tooling made.

For now, the buttercream top casts have been shelved as I think this is the most realistic one. When making a candle or soap cupcake, I'd pour this in two colours - one for the bottom and one for the top. I just thought you might all like to see what makes both my dreams and my nightmares....

All being well, a new mould to recreate a lifesize cupcake candle / bathbomb / soap / very very  big chocolate as above should be available from sometime in May..

Sarah-Jane Nash - http://www.siliconemoulds.com/ - the silicone bakeware specialists. March 2011


  1. OMG - had no idea what went onto making a new mould..
    Hope you are getting some well deserved rest.

    The photos you have look awesome!

  2. Wow WHat a nigtmare and a dream come true at the same time! the cupcake with candle is beautiful! Looks like it was worth all the teouble. I hope youre having a good rest now Sarah.

  3. WOW! That's really no easy job! Love the color of cupcake mold, so pretty with the candle on it.
    Have a good rest :))

  4. My Goodness!
    What an ordeal!
    Its just lovely though, I love the candle.
    Take a nice nap today:)

  5. Absolutely brilliant, but what a trial you put yourself though! As for the playdoh ... you could make some more before Oliver realises (http://www.bigeyedowl.co.uk/FavouriteCraftRecipes.htm )

  6. Awesome!!! Awesome!!! I have been wanting to make cupcake soaps for ages and when your mould comes out I will be first in line to buy!!! Excellente!!!

  7. Well done, I so admire your tenacity. I seem to attempt madly overambitious projects that often don't achieve the final results e.g knitted dogs - bits of dog all over house; pebble mosaic - half a beach in my wheelbarrow and a big hole in the ground plus shoes (quite nice ones) full of cement; and today's effort is a giant cupcake that refuses to budge from its mould. So I think you are a star who proves the end definitely justifies the means. New kitchen? New clothes! New playdough!


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