steam bending ash and maple

[Chubman]

im in the process of making a large crabtree net head in ash or maple the formers made,spreader block and net ordered, and now the bit i am worried about ,steaming the timber strips, is it good practice to presoak the ash before steaming.
another thing im not sure about is the steam box,would it be best to use a small dia steam tube,ie 25mm x5mm timber in a 50mm dia steam tube or will it need a larger volume of steam,please help as ive no wish to ruin it at my first attempt many thanks chubman

[Nobby]

I've watched boat builders doing this and they were all using some sort of gutter downpipe at about 4 inches, so 100mm sounds about right. I think you need that diameter to let the steam freely flow to the far end. I guess only certain types of down tube will take the heat OK.

[Santiago]

viewtopic.php?f=183&t=14680&hilit=dulcimer

When I made a dulcimer for my son last year, I used aviation grade beech ply and pre-soaked in the Thames for several hours and then steamed the ply using a big fish kettle (about 2' long) on the hob until it could be easily bent (about 20 minutes). But you will have to practice, and then thicker the wood the longer the steaming. There's lots of info on steaming wood on the internet, on making musical instrument sites!