I've been working on a new rocket, with long fins, and have decided that I'd like to paper them to strengthen them up, particularly at the top section. The fin assembly is 16" long, which I am thinking may be a bit tricky. The fin edges will be square (not rounded). Any suggestions as to the best way to paper this fin assembly? I was thinking just plunk it down on the paper, trim a little larger than the fin (except on the root edge, which would be flush), make 2 pieces and glue it, working fast.
Yes, good plan.
One single sheet of paper, shape of the fin outlined on it, and glue (TBII for me) spread evenly across the target area, and 1/4+" beyond the target.
I gave up on aiming to be flush with the root edge, since that would require perfect aim during application.
Once the paper attaches to the large surface area of the balsa fin, it 'grabs', and you will not be able to move it without wrinkling or tearing (BTDT). Thus, I expect some error in aiming, and spread the glue a little beyond the target area. Then cut-off or sand-off overhangs after everything is fully dry (12-24 hours later).
If you want to keep edges square (painting those will be a PITA), consider trimming overhangs with a cutting blade right after the glue starts gelling (1-2 hrs?), then stick the fin back under the press until if fully dries.
I haven't had much success with printer paper, as it wrinkles and shows surface defects too well once it shrinks down. I have had better luck with thicker card stock (65lb), but I also don't have any pieces that big (I have 8.5x11" pieces). I did find a roll of paper at Hobby Lobby that I'm going to check out (24" x 100 feet).
Yes, try slightly thicker paper (don't go full card stock, as it will make fins too heavy and effect CG).
There are different qualities of printer paper, and the cheaper stuff is the thinnest and wrinkliest.
Consider buying something of slightly higher quality and weight, and do NOT flood it with glue. Put down just enough glue on paper to spread over the entire target area (multiple finger passes), then remove any puddles (with a finger), then mate paper to the balsa fin. Do both sides as quickly as possible (to avoid warping) and place it under an object heavy enough to keep it from warping while glue fully dries.
I found table cutting mats to work great for longer sci-fi fins that would not fit under a book. You can easily position all fins under the mat at once, and pull them in/out for trimming at will.
The Screaming Eagle build thread I did last year has a few relevant illustration pictures that might of some help:
https://www.rocketryforum.com/threads/estes-screaming-eagle-build.158704/#post-1989643
On the Estes Shuttle pictures below, you can see the areas that got papered (wings) and those that did not (fuselage). On the finished model picture, you can see residual balsa grain showing through the fuselage (after multiple rounds of sanding/painting/sanding/etc.), while the wings are nice and smooth.
HTH,
a
