After a couple days of flipping the fuselage frame in the rotisserie I noticed a couple of oil spots on the floor. An investigation showed that there was oil leaking from the tallest aluminum backbone tube support, and there was evidence of oil in the open end of the vertical fin tube.
I was concerned that the oil would cause paint problems, so I wanted to plug it without a chance for leaking again.
I purchased some oil resistant neoprene foam rubber rods from McMaster-Carr in 3/16" and 3/4" diameters. To clean the fin tube I found a 1/2" aluminum tube in the scrap pile and drilled some 5/16" holes in it to allow a strip of rag to be inserted. I chucked the opposite end of the tube in a drill and after dipping the rag in a cup of acetone, I inserted the tube/rag into the fin tube and let it do its thing. It took about 8 rags, but eventually it came out perfectly clean.
Then I cut about 1-1/4" off the 3/4" foam, coated the end with Dow 730 silicon, and inserted in partially into the tube. After coating the rest of the plug I used the 1/2" tube to push the plug a few inches into the fin tube.
The same process was used for the 1/4" standoff tubes, except I used Q-tips on a stick to clean them out and the 3/16" diameter rubber.
Now back to covering!
Oil on the floor - Coming from aluminum backbone.
Cleaning out the fin tube.
Plug going in - Dow 730 is amazing stuff - Gets on everything...
