Friday, 12 June 2009

laminating the frame: preparing the carbon

Today is the day to make or break the project. The plug will be covered with carbon, or the be more precise: half of the plug. If anything goes really wrong is this stage it will completely mess up the plug, requiring a lot of extra work (like making a new plug).

This is the black gold (at 35 euro ex. VAT per sqm) that will cover the frame:

Laminating a frame like this is not something you can easily do alone (I know, I did it with my first tandem), so today my good friend Andries is comming to help (if he wakes up).

You have to laminate in two stages, because I use a positive plug. If you would laminate it all around in one go, it is impossible got get the material really tight around the plug. When you would put on the vacuum the carbon will start to wrinkle as it has nowhere else to go. Laminating half of the frame prevents this.

My first idea was to cover first the bottom half of the frame and in a later stage the top half. Some discussion with Andries lead to a better solution. We laminate first the right hand side, and later the left hand side. This make the laminating much easier to do.

We start with preparing a cardboard template to cut the carbon.

The templates are used to cut the carbon. We use electric scissors. They are much reasier to use than normal scissors because the cloth can stay still and almost on the table. The cloth is easily damaged as the fibres are quite loose.

The first ply looks like this:

The laminate consists of carbon with a weight of 200 gr/sqm in a keeper weave. we use 6 layers of this. 4 layers have a normal fibre orientation (horizontal and vertical on the frame), the tird and last layer have the fibres oriented under 45 degrees. This greatly increases torsional stiffness.
The result of the work is this:

And of course these expensive leftovers:
The last preparation is cutting the peelply and breather material to shape:

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