Papering fins, first attempt

I was given a Quest "Superbird" kit, and thought that this would be a good time to try papering the fins. The fin material in the kit was kind of "punkish" - not the highest quality balsa, so paper could only help. I doped the fins with slightly thinned yellow glue, and used regular typing paper for the skin. I tried to crease the paper and fit the leading edge into the crease, but this didn't work out too well (but no harm done). I think I over-did it with the pressure. I do veneer laminating to dress up some of my woodworking projects. I've got a couple of pieces of plywood I use as cauls, and clamp the pieces with 6" "C" clamps. I started out doing one fin this way, then realized this limited me to one fin at a time. I glued up the other two fins, made a stack, alternating cauls and fins, and put a heavy weight on top of the stack. I think I used a bit too much weight, because the grain pattern in the balsa printed through the paper. How much weight do you guys normally use?

After everything dried overnight, I trimmed and sanded the excess paper. The leading edges ended up with a thin coat of the yellow glue, and I don't see anything wrong with that. I normally rub in a layer of yellow glue on the root edge of the fins before I glue them to the body. Didn't look like this was necessary with the paper; excess glue has squeezed out to all the edges. Glue-up and filleting went as per normal. Haven't painted yet, so I don't know whether the grain pattern will show through paint. I'm not worried if it does.

This is designed as an 18mm engine kit, with a payload section that is supposed to come down on its own chute. I can never leave well enough alone. I used the payload section as the engine mount. I installed a 29mm engine tube, sized for the new Estes 29mm BP engines. The body tube sizes are very close, so I was able to make the 29mm tube with with two 1/2" wide strips of 110 lb card stock wrap. The coupler was turned into a baffle by gluing in three 1/8" plywood semi-circles, which were coated with yellow glue for fireproofing. This is a nice, long rocket, and I'm thinking of a red/white/blue paint job (usually I just go with one color). Looking forward to sending this one down range!.

Tim from Apogee made a Youtube Video that shows how to do it. I practiced on some Scrap Balsa before doing it on Models. Here it is:

[video=youtube;JnYBSbYr8ZE]https://www.youtube.com/watch?v=JnYBSbYr8ZE[/video]

I've had best results by doing a whole set of Fins, then placing them between heavy Books to let them dry. I find 80lb. Card Stock works best. I've also had good results with Copier Paper. I tried some College Ruled Notebook Paper and it was not pretty.

last few sets of fins I simply spread glue(white), applied and burnished the paper(20# printer), and placed them on a cooling rack. 3 hr.s later I had them stuck to a rocket. I find that if I don't waste time between sides they turn out well, main thing is to have both sides drying at the same rate.
rex

I think you're overthinking it myself... No need for thinning the glue, clamping, etc...

I cut the balsa fins out and stack sand them and sand in the desired airfoil... then start papering... I basically trace the fin outline on a piece of printer paper, with the leading edge toward the center, then carefully roll the fin over the leading edge, and trace it again. Cut the paper out with scissors so that it's about a half-inch to an inch outside the traced outline. I then spread a THIN layer of WHITE GLUE (not school glue-- either Elmer's Glue-All or Aileene's Tacky Glue) over the entire surface area of the bottom fin outline on the paper-- spread the glue as thin and as even as you possibly can-- DO NOT THIN THE GLUE. (Thinning the glue only adds water, and excess moisture is the enemy here!) Then press the fin down onto the outline. Apply a second THIN layer of glue to either the other side of the paper or other side of the fin, and then carefully roll the fin over the leading edge and press it down against the other outline... Then grab a sharpie marker and starting at the center of the leading edge on one side of the fin, carefully burnish (rub) the paper down tight onto the fin... this will force any excess glue out toward the root, tip, and trailing edges of the fin and out from between the paper and wood. Use some pressure, but not excess pressure-- you don't want to impress the balsa grain into the paper or dent the wood beneath. Continue to burnish the paper down completely to the tip, root, and aft edges of the fin, then BURNISH OVER THE EDGES-- I actually burnish the edge of the paper and any excess glue down to itself-- this keep the paper tight around the fin while the glue dries and ensures a nice, tightly glued edge when the paper is trimmed down later. Flip the fin over and repeat the burnishing on the other side, including over the edges. The most important thing is to use AS THIN A LAYER OF GLUE AS YOU CAN EVENLY APPLY TO THE PAPER. I put a few drops of glue on the paper and rub it out thinly and evenly with a fingertip... it doesn't matter if you go beyond the outlines, just make sure everything inside the outline is covered with as thin a layer of glue as you can apply. Glue is actually stronger in a thinner layer, and less glue means less water. If you use too much glue, or glue that has been thinned with excessive water, it will quickly soak into the paper and cause it to wrinkle, and the thinner the balsa, the higher the risk of warpage. Using a thin layer of thick, undiluted glue will avoid these problems entirely. This is probably THE biggest mistake people make papering fins-- using too much glue, and getting wrinkling of the paper or warping of the fins balsa core as a result. Don't worry-- a thin, evenly applied layer of white glue will PERMANENTLY attach the paper skin to the balsa, greatly increasing the strength, and will completely cover the grain if done correctly.

I usually allow the glue to dry overnight, and then trim the excess paper down to within a quarter inch of the edge of the balsa with scissors. Then, using a SHARP hobby knife, I "shave" the paper off down to the edge of the balsa (carefully) until it's flush to the edge. Rolling the paper over the leading edge serves two purposes-- 1) it completely covers the leading edge, and eliminates the seam there that the high-speed slipstream of air passing over the fin would pull hardest against, attempting to rip the paper off the fin-- it's the one spot that is MOST likely to delaminate in flight from the wind resistance, and 2) it totally eliminates the need to trim the paper to the leading edge whatsoever. So going around the leading edge with one piece of paper gives you a stronger, tighter fin and eliminates 25% of the work trimming the fins.

Once you have the paper trimmed down to the very edges of the balsa, if there are any stray "paper hairs" left on the edge, they can be quickly eliminated along with any excess dried glue that might be clinging to the edge of the fin by drawing the fin toward you at a slight angle across a sheet of 240 grit sandpaper held down to the work bench surface. Flip and repeat, and then draw the fin across the paper with it at 90 degrees to the work table surface to make sure all the edges are straight and true. You shouldn't be removing hardly any material, just "truing" the edges of the fin and cleaning them up a bit. A couple of strokes is all that's needed. Do the root and tip edges this way and a light pass with the trailing edge will clean things up extremely nicely.

Here's a thread with details on how to do it and pictures to explain the process...

https://www.rocketryforum.com/showt...d-Eagle-Beta-Build-Thread&p=118648#post118648

https://www.rocketryforum.com/showt...d-Eagle-Beta-Build-Thread&p=118654#post118654

https://www.rocketryforum.com/showt...d-Eagle-Beta-Build-Thread&p=118657#post118657

https://www.rocketryforum.com/showt...d-Eagle-Beta-Build-Thread&p=118660#post118660

Later! OL JR

I've used a good quality glue stick for papering, and it's worked very well.

Rich Holmes said:

I've used a good quality glue stick for papering, and it's worked very well.

Click to expand...

+1

Trace the fin onto a piece of paper (even junk mail credit card applications), then take the glue stick (I like Avery's Permanent Glue Stick) and cover the desired area on the paper with a heavy load of glue (paper starts to soften). Press your fin onto the paper. Rough cut the fin out. Press out the wrinkles starting from the center and working out (finger pressure). Trim the edges. Repeat for other side... quickly. You can finger press out any warpage if you work fast enough (Read: Do one fin at a time, both sides, and you'll be fine). Use thin CA to harden the exposed edges, and hitting it with CA Kicker won't ruin the paper. After that, and you can glue the fins on immediately.

Rich Holmes said:

I've used a good quality glue stick for papering, and it's worked very well.

Click to expand...

+2 on the glue sticks.

I used to use a thin coat of white glue to paper fins but for me the glue stick works better.
You have a little more time to position the paper skin and there's no chance of over saturating the paper.

I've also been using glue sticks for body wraps like in the Dr. Zooch kits.

I don't mark the paper or cut it to size, but rather leave it oversized and align to the root edge of the fin. Once dry, I sand all but the root edge round and the excess paper falls away.