Sunday 27 March 2011

How to make a nest concave out of Modroc

Contributed by Dick:

We have been casting around for a method, suitable for children, of making nest concaves. The answer could well be Modroc - plaster of Paris bandage: it is cheap, simple and quick, and the resulting concave looks ideal for Swifts.
All you need is a suitable plastic food container, something to make the concave impression (e.g. bluetack, plasticine, papier maché or Modroc), Clingfilm and water. We used a Tesco's finest vegetable curry bowl 120mm in diameter. The concave former should look like an inverted saucer 9cm diameter by 15-20mm high and should be wrapped in Clingfilm to stop the Modroc sticking.

Place the concave former in the centre of the food container, then cut two broad strips of Modroc, soaked in water across the centre. Then cut narrower strips (say 50mm wide) for the sides, building up the rim until it is at least as high as the concave former. Level off the edge of the rim.

A few minutes later you can turn the concave out, remove the former and then start the next one.

This concave is destined for the Cambridge Swift Tower.


  1. Is it possible to make concaves out of home made Play Dough?

    1. I guess it would be possible,I would guess the Swifts would accept it, and if it is safe for children it is probably safe for Swifts. It would also be easy to stick a few feathers to Play dough.