I hadn't done any tissue work since the 1970s. I thought I remembered the technique, I just had to buy clear dope and tissue. It took a little searching at the hobby store to find it. By the looks of the envelope, I don't think many people take the time to do this anymore. After some Internet searches I had refreshed my memory on how to do it. I still screwed it up.
I forgot to check the "grain" of the paper before cutting it out. You find the grain by tearing the corner of the sheet. Which ever way it tears easiest - that's the length or run of the grain. The long grain should have run down the entire length of the blade. I ran it the wrong way. Oh well, it's still stronger than it would be without it.
The blades got two coats of clear dope, sanding lightly between coats. You aren't sanding down to the surface, leave a dry coating of dope.
The tissue is cut slightly oversize. Note how it is layed down in the picture. One straight side of the tissue evenly overhangs the front of the rotor. This will wrap over the leading edge and onto the flat bottom.
This overhanging edge insures full coverage of the tissue. (Sorry the picture is out of focus, it's just the way it turned out.)
The tissue is set in place and a light brushing of thinner is applied over the top. The thinner permeates the tissue and goes into the dope on the balsa rotor. This now thinned dope locks the tissue onto the surface.
In this picture, the airfoiled top has the tissue in place. Here I'm rolling over the straight overhanging edge over the edge onto the flat underside.
It doesn't take much thinner to to break down the underlying dope coats and adhere the tissue. I dip my brush into the thinner then take off some excess on a paper towel before going over the tissue.
No comments:
Post a Comment