Home Made Duct Work

Give some detail on the process. 1. you make a solid tube the shape you want..then??

The solid shape was made from balsa and foam:









Then fiberglassed, finished, and painted with automotive paint.

Due to the shape the mold needs to be a 2 part mold. Flat plastic is bolted to 2 sides of the plug. (One of these is actually an old aircraft window out of the King Air.) The plug is further divided by 2 more pieces of plastic. Plastic and pug are waxed (actually before assembly). Once assembled clay fills the gaps. A release agent is sprayed on. Once dry the fiberglass and resin is layed in to make one side of the mold. That is as far as I have gotten so far.

OK, I see the red tube in the foreground. That made the half mold. How do you intend to keep it hollow when you pour it? And what will you make the tube out of?

quote:

Originally posted by lastpushbutton:
OK, I see the red tube in the foreground. That made the half mold. How do you intend to keep it hollow when you pour it? And what will you make the tube out of?

LPB the carbon fibre is layed up and then the mold joined. I will be flying tomorrow but hopefully have some seperated shots Wednesday.

Notice the 2 doll rods in the side of the mold for alignment:

far from perfect but it will work. Not good enough to leave in carbon fiber color. I have a few voids I will have to fill which means I will have to paint it. If I get in the mood this winter I may re-make the molds and try it again. If I pull one out without air pockets I won't have to paint it.

Very nice work!

Gary, How about some kind of inflatable bladder.....like a balloon inside? Put the two halves together and inflate it from the end..Do you use conventional resin and hardner?

It's just practice and methodology. I think I can do it well but I got to start by making a little better molds. In reality I rushed the process a little. It's ok for a single part which I will paint but not ok for production parts. Its the little details that catch you. If I needed to do it all over again I think I could make a near perfect part but I am going to move forward from here. I got the part I need. The only difference is this will have to be patched and painted where a perfect part wouldn't have to be.

The resin is polyester but I think for carbon fibber would be better if it was epoxy.

Gary be carefull when you go to sand it. I heard carbon fibers will go right through the sandpaper and poke you in the hand.

LOL, just working with it I have a few pieces shoot right through my plastic gloves.

quote:

Originally posted by comp2:
LOL, just working with it I have a few pieces shoot right through my plastic gloves.

Splinters, Reminds me of a friend of mine. There was a F16 military jet crash and some guys picked up the peices out of the water. My friend picked up a peice out of the truck bed and got a splinter of Berillium in his hand and it swoll up and almost had to be aputated. Scary stuff