Just thought i'd share this.

http://www.instructables.com/id/EUAJPQ0F2FRV86O/?ALLSTEPS

Steve.

Some interesting stuff there. I liked the 'lost foam' method of making ducts.

He didn't say much about how to get a smooth surface on the moulds, though. I know from experience that that is probably the hardest part of the whole process.

I wonder what the UK equivalent of the clear packing tape is? Brown tape can be quite difficult to remove. Maybe sellotape?

You can get celotape in the same size as brown parcel tape. Polyester resin doesn't stick to either, which is nice for making small parts without moulds.

I use an old window for making flat pieces. Lovely smooth finish and it doesn't stick.

That reminds me of the method of making odd shapes with polyester fleece material. You stretch the material over a former and simply wet it with resin. The result is suprisingly strong.

remember I was asking what material to make ribs?

in the end I used two methods:

1. bubble wrap rolled into a tube and held in place with sikaflex type stuff. lay the CSM over the top. What can be lighter than air and some plastic? .... but I foudn that the epoxy does not stick to it so it can be pulled out.= - even lighter and neater

2. carboard covered in polyester sheet - the stuff that the resin does not stick too. once set, pull out the carboard and then the sheet.

oin both cases one end of the rib is open -clearly this could not be done if it was sealed.