Monday, September 03, 2007

One more wingnet rail, and notes on how to destroy a vacuum table

This is how the wingnet support rail that I made yesterday looks like. I think it is very much like I hoped and expected. Very stiff on the long side, quite sloppy on torsion:


Here is the underside. Sorry, not a very good picture. It looks cool in real life, though.


It is now resting on top of the float, waiting for the heat cure in the "tent". I am looking forward to see how I will make that one, and whether it is going to work....


The mold is hollow as you can see on earlier posted pictures. Yesterday, I put it on the table and secured the vacuum bag to the table. As I was infusing yesterday I suddenly heard a loud bang and the vacuum dropped to about 1/2 atm. The resin was already distributed evenly, thanks for that. I could not find the reason for the bang nor the source of leak until this morning. It turns out that the vacuum inside the mold had lifted the Vinyl cover glued to the table until it tore apart, quite impressing forces in this vacuum, consisting of nothing, actually. Tomorrow I have to fix my table before I can start infusing all the flat panels for the main hull. Close up of the leak:


I had to obtain vacuum in another way today. What I did was putting the mold on top of the old deck flange molds from the float half production setup and wrap it all in a bag. With all layers and tubes in place, just starting to evacuate the air it looked like this:

Here is the complete infusion set up. Resin in the bucket down right is being sucked in to the bag and distributed along the mold trough the spiral tube in front. Resin then being distributed trough the resin distribution media (RDM), blue color, and trough the tiny holes of the release film being the next layer from top. Then all the tiny spaces between the fibers of the peel ply and the different layers of carbon and aramid formerly filled with air, at this point nothing, are filled with resin.

The vacuum pump is connected to the resin trap in the background which in turn is connected to the collecting spiral tube running along the back side of the mold. This means that all the resin not being trapped in the tiny spaces of nothing (above) leaves the story and have to be brought to the dump on a given day. This leaves a part totally free of bubbles and with a fiber to resin ratio of up to 70% providing the best possible strength to weight ratio:


The part will be left under vacuum for at least 10 hours. Slooooow hardener.

1 comment:

Tom McCaw said...

Great photos of the process....thanks Tor

Tom
F22#45