Cornice

All three of the window mouldings have now been re-attached and it is getting closer to the time for plastering part of the bedroom. The hallway is still not finished though – the cornice is broken where the old electrical circuit breaker was. This needs to be done.

  

The materials have been available since August but it is a job that has been put off many times and often just forgotten. The idea was to make a mould and then cast the replacement bit of the cornice, using Alginate(made from kelp) and plaster of paris. The suppliers were very helpful when my needs were explained to them over the phone. The original intention was to make a mould for the full cornice ie. include both the vertical and horizontal parts but this meant that the mould would be very large and there was not enough Alginate. It was decided to mix the Alginate on a board and then to press this up against the corner and lower section. The instructions say -mixing for 50 secs – it then starts to set for the next  3 -4 minutes. This meant mix, put on board, get up ladder, press into place (quickly) and then hold in place for a few minutes. Much of the Alginate was wasted on the upper section and the  length was not as long as hoped for but if two plaster casts were made there would be enough for the repairs. The ends were cut off and two triangular wood end pieces added.
  
Wait! This did not look like my cornice ! but of course, it is a reverse shape. The instructions mention ‘boxing in’ the mould but I decided to tilt it all so that when the plaster was pored in gravity would provide a flat surface, to fit against the wall. A hammer lodged under the base provided the tilting mechanism! A few experiments were done first to get the right plaster/water mix.(It always helps if the calibrations on the mixing jug can be read properly!) The wooden sides of the mould and a little front piece were held on by small panel pins and when the plaster had set, the wood was just pulled apart and the casting removed.
 

Two of these castings would be enough but they would have to be worked on first to fit fairly flush with the original. Originally a hack saw blade was used but it was soon realised that a tenon saw and a wide wood chisel would work better. The rear gaps in the cornice were filled with normal plaster, the casting pressed into it and the narrower slots filled later with filler. It was done in three pieces with about 2 ins of the castings left over!
 
The fitting was a bit of a mess, more time and care should have been taken with cutting the casting to fit the recess but done carefully, filler and finger can work well.