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Slip casting found objects eg:teapot

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If you do make a mould from a found object, the final slip-cast version of that same object will be smaller than the original.

If you are happy with that, see this thread (can't find thread, copied from one of my handouts instead):


Mould Making


Some very basic steps to make a two-piece mould, assuming your mug is symmetrical and has no undercuts and is flat footed:


1.             Make a sample mug that you like.   Make it thick or solid. Keep it wetter than leather hard.

2.             Lay mug on it's side supported by "old/scrap" clay.

3.             Put scrap clay up to half-way up the sides, make sure it is level and flat.

4.             Press 4 marbles into flat clay, to make registration marks, so the two halves of the mould line up.

5.             Put a plug of scrap clay inside mug, extending 2inches beyond rim.  (Inside and not covering top of rim, and tapered like a funnel.)

6.             Build walls around clay and mug, varnished plywood is good.  Wood should be at least 2 inches taller than height of laying down mug, and 2inches further from mug all round.

7.             Secure wooden walls with clamps or straps.  Plaster is strong and heavy and it will escape if you let it.

8.             Seal corners inside or out whichever is easiest with scrap clay.

9.             Apply three coats of soapy release onto wood and marbles, allowing to dry between coats.

10.         Calculate volume of plaster required - w*h*d/10 in centimetres gives volume in litres ( 30cm x 30cm x 5cm  = 4,500 or .45 of a litre.  (12" x 12" by 2")

11.         Mix plaster using amounts as per photo below.  (Water in bucket first, then sprinkle plaster, wait 2 minutes, stir gently for 2 minutes - stir with rubber-gloved hand, making sure no lumps.)

12.         Pour plaster into box.  Don’t aim first part of pour onto mug.  Lift baseboard up and drop gently a couple of times to bring air-bubbles to surface.

13.         Leave 1 hour.  Remove boards and clean up.

14.         Remove scrap clay, but leave rim plug in place.

15.         Turn plaster block and original mug over so plaster is now on the bottom.

16.         Twist coin or similar into plaster in two places on each side of mug, making an inverted dome.  This will keep the two halves of the finished mould located.

17.         Build walls up around as step 5. 

18.         Repeat steps 6 to 12.

19.         Use a rasp/surform to remove sharp corners on outsides of plaster.

20.         Leave to dry out for several days.

21.         Remove plug and original mug.

22.         Clean soap from plaster with vinegar.

23.         Put rubber bands or strap around and leave to dry for several days.  Moving air is better than heat.



It is worth spending time to read up about mould-making - best book I've come across is this one: https://www.amazon.c...s/dp/1600590772







©  Copyright Ann Allen.         ann.chil@yahoo.co.uk


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