Hello again! And I think I can still just about get away with ‘Happy New Year”.
I’ve been at it again – stinking out the house with the aroma of burning wax and hot metal.
Whilst abluting on New Years day I looked at my Gentleman’s grooming accessories and decided leaving a razor sharp, um, razor lying around wasn’t great and the soap and brush do make a bit of a mess of the tiles. So I resolved to make myself a shaving bowl.
My starting point for this slightly ambitious and random undertaking was the remnants of some seasonal packaging. This may have held chocolates or soaps, I honestly can’t remember but to me it’s the perfect former for a bowl.
Lost wax is the name of the game – again – I will use all the damned stuff, one day, or get bored in the attempt. To make my basic shape melted wax is poured in, the two hemispheres are hastily closed and the whole thing shaken until the wax sets.
Whilst the wax is still pliable a pair of scissors does a neat job at making two convincing looking bowl blanks.
For decoration I used the ginkgo leaf mold – soaked in water the plaster happily takes wax.
A hot skewer ‘welds’ the leaves in place and then the fragile wax bowl gets its first filling – a good solid core of plaster. Once it’s set I’ve got something much more robust and can tidy up the wax without fear of squashing it.
To make the body of the mold it’s essential that there’s no trace of air bubbles. A thin plaster mix with a drop of detergent is quick to brush on and gives good coverage ( though it totally buggers the brush). As soon as it’s set – but still wet – the bulk of the mold can be made. I want this layer to be porous to allow gases to escape so I add vermiculite.
The top of the mold is a bit more fiddly. An old tub hacked about with scissors and half bakedly fixed in place with flour paste holds the next load of plaster. The food colouring gives me a hope in hell of seeing the join between the two halves.
Now for the clever bit – I reckon the cavity left by the wax was too thin to make good layer of metal. Carving and sanding of the dome section widens the gap a bit, the outside surface gets a smoothing and tidy up with some wire wool.
Casting time – if it doesn’t work first time I can’t recover the mould, one bubble is all it would take. No recycling of hip flasks here – I need metal designed specifications lly forr casting that will flow freely.
The plaster gets warmed – not enough to be out gassing all over the place but enough to slow setting.
Basic blow torch, pliers and old can – my standard kit, plus a fire brick and a house brick. The actual casting is a doddle – heat metal until it just starts to skin, pour. Put top on as quickly as possible and since plaster floats in metal, shove the house brick on top.
A good hour later and I figure it’s probably set – or thermodynamics is broken. Tentative tapping is in order. The first blow takes the top off and gives me tantalising hint of a circle of metal – a good sign.
This all looks good but it’s too bright and shiny, I think pewter looks better with a patina. My best patina comes from concentrated nitric acid brushed on ( don’t ever do this, it’s really plucking dangerous, only an idiot would use it).