Weird Plaster and Epoxy Experiment(!) And boringly practical lessons-learnt

 I made this:

I was going to say it's weird and I don't know why, but that's completely untrue, which is interesting in itself as, actually, I know exactly why I made it! I made it as a test of mixing plaster and epoxy in the same mould, and because I thought it would be interesting/cool! A few pieces I've made I have wanted to have a block of plaster with an irregular cavity filled with epoxy - firstly because it adds to the possibility of the 'peering' aesthetic I'm exploring, and secondly because I have a love/hate relationship with epoxy, so the less I need to use for a given overall size of piece, the better!

The method was very straightforward (if a bit fiddly):

1. Cast the head
2. Put it into the cube mould and fill the areas of the mould that are supposed to be plaster with modelling dough
3. Fill the remaining space with epoxy and wait for it to cure
4. Remove from the mould and carefully remove the dough, leaving an irregular half cube of epoxy with the head stuck in it
5. Return it to the mould and fill the void (that was dough) with more plaster

So having ripped the veil of mystery and allure from this piece, these are the lessons it taught me:

• Epoxy will cure next to modelling dough, despite the modelling dough being a bit wet (epoxy has no love of water)
• The modelling dough is quite tough to remove from the block of cured epoxy, so best bet seems to remove as much as possible by hand, then resort to hot water and a pointed tool
• Epoxy dye doesn't mix with plaster! I was stupid to think it would because the epoxy dye is clearly oil based like the epoxy... Needless to say, I realised this a few seconds after I poured it in...
• Uncured epoxy soaks into dry plaster, giving it a lovely texture and beige colour, but it means the pure white head above looks DARKER than the grey plaster around it, because the grey plaster is added after the epoxy cures
• Cured epoxy floats in plaster! This meant that as I was pouring the level didn't appear to be going up because the epoxy was floating up with it! Squashing it down results in a fountain of liquid plaster and it bobs up again... So you have to keep squashing it down until the plaster starts to set, then top up with more plaster if required
• The top surface is quite irregular as it has the meniscus of the epoxy and the extra plaster top-up. It is therefore probably best to cast whole thing upside down so the good bottom surface becomes the top, and the crappy top surface is hidden at the bottom
• Modelling dough sags over time, which wouldn't be a problem except that the epoxy takes several hours to reach a point where it's no longer flowing. This means that the final shape left in the epoxy is much saggier and softer than the one that was there when the epoxy was poured - the interface between the epoxy and dough was much more angular and 'rock-like' when it was first poured

Much as I hate to say it, I should probably try again, but reverse the order - use the dough to block where I want EPOXY, then cast the plaster, remove the dough, and cast the epoxy. Doing so would almost certainly resolve a number of the issues above, BUT might cause new problems as the dough might dissolve in the water in the plaster... ALSO, if I follow this approach, I'll be force to shape the dough upside down AND in the negative - i.e. with the current approach, I can mould the dough to be what I want the plaster to look like, with the revised approach, I'd have to mould the dough to be what the CLEAR areas will look like.... Which is a bit of a head fuck...