Dave Parizo Shares some Good Info on

Bladder Tube Construction

There is always a part of building that creates problems for the builder. Mine was the piece of balsa that joins the exit of the bladder tube to the curved surface of the wing where the fuel line passes thru. I was hand sanding a curve to match the curve of the tube. This was not something I enjoyed. There must be a better way. I saw a tablesaw technique in a woodworking magazine a few years ago. The technique was how to cut a cove in wood using your table saw. I tried it on a piece of 1/4" X 3" balsa. It worked great. I set a piece of wood as a fence 22 degrees across my blade. The blade is raised about 1/8". The blade must be a sharp high quality blade. I was able to cut 24" of coved wood. This worked great. just rip and crooscut to size. Give it a try. If you do not feel comfortable doing this technique, send me an Email with your address, donate $10 to the NECN combat fund and I will send you a 12" piece of coved balsa. This will be 3" wide and 12" long. Should cover 9 or 10 planes. Take a look at the photos for details.

I drill a 3/4" hole using a sharp forstner bit and heat a piece of 1/2" conduit into the bladder tube. nice fit.