The fins on this particular rocket are really long and thin, (by long, I mean the root cord), and since I've never papered a fin before, I decided not to try it with this one.
But since we're talking papering fins, what adhesive do you prefer? I've heard rubber cement, wood glue, even glue sticks. I did try a papering experiment with a piece of scrap balsa I cut into a quickie fin shape. I tried Apogee Components' method of using wood glue, then using fingers to squeegee off most of the glue. But it got so thin, it just dried to my fingers and got all rubbery. Didn't go so well - perhaps I needed to leave more of it on. But I want to try papering soon.
Also, do you prefer the wraparound papering technique, or do you just use two pieces of paper, one for each side? I guess your answer might depend on whether you round or airfoil the fins, or just leave them square...
I just use plain old white glue... works perfect.
I cut and stack sand the fins and sand them to the desired airfoil shape (usually teardrop, but sometimes wedge for scale rockets that had them where they look more appropriate, despite the additional drag... rarely I just round over the leading edge, especially if they're THIN fins like 1/16 balsa or something). I then take regular printer paper, and cut it into squares large enough so that BOTH sides of the fin can be covered at once with the fin rolled over the leading edge. IF you want to make sure, lightly trace the fin outline onto the paper, gently flip it over the leading edge without allowing it to slip, and trace it again. This helps to get everything located properly the first time you do it, in fact. I like to have at LEAST 1/2 inch to an inch of excess paper all the way around the fin.
Take your regular white glue and smear a little onto the paper. With your finger, rapidly spread it as thin as you can get it, across the ENTIRE SURFACE of the paper that will be glued to the fin on ONE SIDE. (You CAN do both sides if it's a fairly small fin and you can work quickly-- I recommend to start you do ONE SIDE AT A TIME. Basically, ensure that the ENTIRE area you outlined earlier is completely and uniformly coated with as THIN a coat of white glue as you can possibly get... the excess glue can extend beyond the outline-- in fact, this is better... just make sure the glue coating is THIN-- this is the real trick to getting it to work well. Once you've quickly spread the glue thinly across the entire surface of the paper where the fin will go (inside the outline), take the fin and press it FIRMLY down onto the paper. Now apply more glue either to the fin itself or to the other side of the paper, working it out as THINLY as possible, covering the entire surface where the fin and paper will be pressed together, extending past the outline if you're applying the glue to the paper. Then, carefully fold the fin over the leading edge, just roll it over, right onto the other side of the paper, and press it down firmly. Using a nice rounded smooth object (I prefer a sharpie marker for this) firmly but gently burnish the paper down to the wood, sort of like a rolling pin, but without the rolling action-- just slide the smooth plastic sharpie pen barrel across the surface of the wood/paper, starting from the leading edge and working your way back toward the trailing edge, and outward in both directions from the center to the root and tip edges. This will squeeze all the excess glue out from between the paper and wood and give a MUCH stronger bond. It sounds counterintuitive, but actually, the thinner the glue, the stronger the bond! This will also ensure that the ENTIRE SURFACE of the paper is STRONGLY bonded to the wood of the fin. If you spread the glue thinly as recommended, this step won't take but a few seconds, and the fin will be sharp and tightly covered with paper. If you have too much glue, the paper can wrinkle or even tear from getting too wet and being worked... next time, use less glue and get it thinner... Once the entire top side is burnished down, I usually take the rounded tip of the sharpie marker and run it around the edges of the paper, pressing it down to itself, creasing it over the tip, trailing, and root edges of the fin, sealing the fin into the 'paper sandwich' like one of those vacuum seal food bags or space saver bags... Then flip the fin over, and repeat the burnishing process the same way on the other side of the fin, including the "go around the outline" of the fin tip, trailing,and root edges.
Set the fin aside to dry, usually overnight. Next day, trim the excess paper off the fin down to about 1/4 inch from the wood itself on the tip, trailing, and root edges. Then, using a SHARP hobby knife (new blade is best) CAREFULLY shave the paper away down to the edge of the wood... just gently slice it away until the blade is flat against the edge of the wood. Now, dress the final cut and shave off any stray "paper hairs" by GENTLY drawing the fin across a piece of 220 grit sandpaper laid flat on the table, tilting the fin at a very slight angle so the very paper edge is against the sandpaper. One or two LIGHT strokes across the paper should do it. Flip the fin and repeat, on both sides of each of the tip and root edges. If the fin was sanded to a teardrop shape, usually the trailing edge will have the paper glued to itself right up to the edge of the wood, and I try to leave just a tiny bit of this "glued to itself paper" along the trailing edge, encapsulating the fin.
This method has some distinct advantages... first, it uses common building materials, it's inexpensive, doesn't require special materials or complex procedures, and it completely covers the leading edge of the fin with paper, so there's no possibility of the slipstream ripping the paper away from the fin, since there is NO exposed paper/wood joint there, hardened by CA or not, a joint can STILL rip loose given the right circumstances... no joint=no problem. This method adds VERY VERY little weight-- surprisingly little, in fact... on one build I weighed the fins before and afterward... it was less than 1/3 gram per fin! The strengthening of the fin is substantial... they're not bulletproof, but about as close as you can get to it with balsa and paper... (hey, if you want an antitank round, just go with fiberglassed plywood and call it good LOL
) Best of all, this method COMPLETELY fills the exposed grain of the fin and leaves you with a nice, smooth, papered surface ready to be primered, sanded, and painted, once the fins are glued onto the rocket... There's also no danger of sealing off the pores of the wood and getting a poor fin/body tube joint like you get with CA glue applications to seal paper seams to the fin along the leading edge.
I experimented with different ways of doing it and this is the best results I've found and the easiest method FOR ME. Others prefer pre-glued label paper, or wood glue, or gluing paper to the sheet wood and then cutting the fins out, or papering the fin and then sanding in the airfoil and sealing the paper edges down with CA, and if it works for them, more power to them, but honestly since I started doing this on my builds, I don't do it any other way... just too simple and the results are too good to bother with anything else, and none of the drawbacks of goofy CA and fumes and mess and exposed grain along the airfoiled edges and exposed paper joints in the slipstream and all that...
The main trick is to use JUST ENOUGH glue to stick the paper and wood together... not so much the paper will soften and tear, not so little that it dries out before the fin is glued down to it. The nice thing about PVA glue (white glue) is that, you can remelt the glue with a hot clothes iron (don't use one you use on good clothes, because if any glue cooks onto it and then gets on clothes it can ruin them-- use an old one, or one you pick up for a buck at a yard sale, or a "covering iron" for model airplane iron-on coverings) and iron the paper down onto the fin-- PVA glue will remelt with an application of heat (NO steam!!!) and "weld" the paper to the wood... (this same method has been used to make homemade body tubes, using strips of paper which have been coated with a thin layer of white glue and allowed to dry completely before rolling them around a tube mandrel, and then applying a hot iron to soften the glue and weld the layers of wound paper together... using this method, there's really no reason why one couldn't apply white glue to paper, let it dry completely, and then IRON ON the paper to the fin on one side, roll the leading edge over the face of the iron to weld the paper down to it as the fin is flipped, and then iron the paper down to the other side of the fin. I haven't tried it that way myself, but the theory has been used in other applications as mentioned...
If you leave the edges of the fins square, it's a LITTLE more difficult to roll over the leading edges and get a nice, crisp, straight crease along the leading edge-- and you want to make sure there is as little "excess glue" trapped between these "double creases" on either side of the thickness of the fin as possible. I did flat slab fins on a TLP kit (TLP Maverick) this way, and it's a little more trouble, but doable. You just have to be careful to get the paper to crease smoothly along one corner edge as you roll it onto the leading edge, get the paper burnished down to the edge of the balsa, and then crease it again along the second corner edge as you roll the paper over onto the other side... sort of an extra step in there I guess... but it works... and the balsa is COMPLETELY contained on three sides!
Don't bother with yellow wood glue-- the stuff it TERRIBLE in this application-- when spread thinly, it dries FAR too fast and gets WAY too tacky too quickly (as you experienced). PLUS, yellow wood glue is actually not as strong bonding paper to wood as white glue is, when it comes down to it... Spray adhesives are messy as all getout, and usually not permanent. Rubber adhesive and contact adhesive and stuff is messy, hard to apply, and hard to work with, and may or may not be permanent, and frankly, just don't bond paper to wood as well as white glue does. Label paper adhesive isn't meant to be permanent either. Done right, white glue papering of fins WILL be permanent... as permanent as things get in rocketry anyway... CA gives off fumes, can get hot, and seals off the pores of the wood so that wood glue cannot penetrate to give a good strong bond when you glue the fins to the rocket... If you're going to use it, make sure you do a double-glue joint and apply a layer of wood glue to the fin root edge first and let it dry so that it's had first dibs on soaking into and bonding with and sealing off the pores of the wood to its content first... this will ensure a good double-glue joint bond between the fin and body tube. Better yet, skip the CA entirely and save it for hardening cones or transitions, where it really shines...
later and good luck! OL JR