I have been asked to design some scenery for my daughters' ballet production in a theatre. They would like a castle arch through which the cast would enter onto the stage.

My arch needs to be free-standing and quite light for children to be able to move on and off stage. I had thought of making it out of hardboard rather than plywood, with supporting laths on the back.

But how can I make it stand up? An idea was to create some kind of easel on the back - a hinged piece of wood with a piece of string at the bottom to stop it splaying out too far. In the giant's castle you mention a hinged book flat, but I am not sure what that is.

I would be grateful if you could give me some ideas of how to make my flat stand up.

Regards
Clare

Hello Clare,
First observation. Thin plywood is much lighter than hardboard and also more rigid so you will not need so much support at the back. But plywood is dearer unfortunately. You are looking for the thinnest plywood (ie about 4mm thick)
There is a thinner one called "aeroplane ply" which is so thin you can roll it up and is used by aeromodlers to make their aeroplanes, hence the name. Don't get that - too flimsy and way way too dear.

If you use plywood then you can get away with using "2x1" planed timber laths for support at the back.

Before I go any further I really need to know the answer to several questions.

What is the total height of your proposed arch?

What is total width?

What is width of inside arch?

What is height of inside of arch?

How to support the piece (or pieces) depend upon these dimensions.

Footnote - Clare never did reply so I could not help her..

I have done this drawing with ink outlines purely for speed. But when it comes to painting scenery I very rarely use outlines. (There's no ink outlines in real life) mind you when I do use ink outlines it is to emulate a childs picture book and as this is for a children's ballet then this might be the effect you are after.

I note you are in a theatre. Any chance of a stage hand helping to erect this arch? If so the neatest way of holding up a flat is to use a stage weight and brace.

Just check with the theatre what length is their brace (Usually about 2.5 metres or more) and then screw an eye on the cross peice of each flat at that height. Theatres usually have many braces and weights, the braces being of various lengths.