Pat Southwood on mon 25 nov 02
Hallo,
Dawn asked about hump moulds and evening classes.
In my experience they do not go together at all. Unless you have a sweet
technician or colleagues who will repay a favour. In one of my classes I am
lucky enough to have a technician who will de- hump and wrap for me after
about 4 hrs. This is a luxury, I know. He also brings tea...
I digress....
Only let them use shallow hump moulds, dont let the edges go to low and
undercut the hump. Otherwise you will never get the damm things off.
With a press mould the absorbancy of the plaster makes the clay shrinks
inwards, with a hump mould the clay also shrinks inwards. - Towards the
centre of the hump. This is why it cracks, because there is a hump in the
way of the shrinking clay.
You could try covering the mould in clingfilm, but this will leave a
texture.
Get them to have it well planned out so that they can go for it straight
away and not diddle about. At the end of the lesson (assuming a 2 hr lesson
at least) you should be able to go round the edges of a shallow mould and
gently release it from the edges, once you can lift it a bit you can
generally work your way round it and get it off. Let it sit, wrapped loosly
on its rim, or on its base if very shallow, and they can trim it up with a
surform next week. They will just have to accept that making a hump mould is
a two week process.
Alternativly why not spend a week teaching them all mould casting and cast
press moulds from your hump moulds, just remember to put on loads of release
goo.
Or, use clay hump moulds, thrown on the wheel, which you could saturate with
water before use and might keep till the next week.
Tell them not to be so impatient!
There is no need to get into the "pot a week " mentality, if they are not
good pots, due to rushing, then they have wasted their time totally.
If a job is worth doing, its worth doing well.
It only takes a few minutes with a sharp knife or surform blade to tidy up
a pot the next week
Have fun!
Pat.
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