Papering balsa/ply Fins... A foolproof method

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K'Tesh

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It's no secret that I like papering fins far more than using sanding sealer (it's cheaper, less toxic, and easier to do). That said, I've had a few that still manage to get messed up... runs of thin CA (used to seal the edges) that I've found can be seen under some of my earlier paint jobs. Now I think I've finally cracked it. This method is being used to get rid of them once and for all.

I'm a fan of Avery's Permanent Glue Stic, but that's hard to find. My new "Go To" glue stick is Elmer's All Purpose Glue Stick (I find mine at Office Depot). I won't touch Scotch's Wrinkle-free Glue Stick with a 10 meter cattle prod... IMHO that product is pure C**P. It's gloppy, and doesn't spread evenly, this makes it totally useless for papering fins.

First I cut the fins out (unless I'm using a paper template), and sand them to shape, and round (or bevel) the edges (except for the root edge).

On a clean surface, I lay the fins out on the paper I'm using (typically just your average office photocopier/printer paper, occasionally junk mail). I trace the fin out with a large border. If the paper is printed on one side, my tracing is done on the printed side. If it's printed on both sides, and I don't have space w/o print, I'll just recycle it and find something that I can use.



I then remove the fin, and use the glue stick and completely cover the area I've drawn with a heavy coat of glue. I'm not worried if it wrinkles a little, I just try not to crease it.



Next, I gently place the fin back into the glued area, and cut it out with a border. If there's a TTW fin tab, I use an Xacto to cut a couple of slits to prevent the paper from lifting up at the corner between the root edge and the tab. [EDIT] I didn't get a chance to photograph the process before I moved to China... I had to improvise this. The red lines indicate the slits. [/EDIT]



Next, I rub the paper down onto the fin starting from one point and working out from there. I want to remove all the air pockets trapped under the paper. When finished, the fin should be smooth and without bubbles, wrinkles, or creases. It is very important not to let any contaminants get sandwiched between the paper and the balsa, as these may create raised bumps that will need to be sanded out.

Next I use sandpaper to cut the border off, while blending the two materials together.

If some paper peels up, carefully pull up the edge, and I use the glue stick to re-apply glue to the fin, then smooth the paper down again.

Now for the new step...

To seal the edges, I now am laying a line of Thin CA glue (the stuff that runs like water) onto a piece of paper that is laid down on a surface that won't be ruined by any CA spills. I squeegee the fin's flight edges (not the root edge) through the glue. If there are large "wet" areas, I use a paper napkin or kleenex to wipe the excess off. From there, I just let it cure. This prevents the drips that create raised areas which can be visible under the paint. [EDIT]For the root edge, use white or yellow glue if needed.[/EDIT]

Finally, I knock down the hardened fuzzies with some sandpaper, and the fin is ready to glue in place.

Occasionally, I've found that the paper will wrinkle with a heavy coat of primer... All is lost!!! Right? Nope. I let it dry completely, then try to find the wrinkle... I have yet to be able to, and I doubt that you'd be able to either.

As with any method that people may decide to try, remember to experiment with it on scraps of balsa first. I'm happy with my method, unaltered, but you may find that an alternative idea that works better for you.
 
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ChrisAttebery

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Thanks for writing this up. I only used papered fins for the first time a month ago on my son's Apogee Avion. I used Avery inkjet printer labels and they came out great. I think that your method of applying the CA to the edges is a great idea. I'll try it out next time I build a LPR.
 

Rex R

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if you're using white or yellow glue to glue the fins in place, I would suggest using CA after they are installed, CA has a habit of sealing the wood so the glue doesn't stick as well.
Rex
 

K'Tesh

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if you're using white or yellow glue to glue the fins in place, I would suggest using CA after they are installed, CA has a habit of sealing the wood so the glue doesn't stick as well.
Rex
Edited the OP to reflect your point... I've also added a link to my method of attaching TTW fins.

Again, CA for leading, trailing and tip edges, white or yellow glue for the root edge.
 
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Major Tom

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I'm trying to picture the "squeegee" part, but I will have to wait for the photos to be sure. I am horrible at getting the sanding sealer to look just right, and the papered edges are tricky. I have tried to sand the surface edges after the paper is on but it always shows through and looks like junk. Thanks for the idea.
 

K'Tesh

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Might be a few days before I can demonstrate "squeegee".

Imagine this... you drag the edge you want to seal across the line of glue, like you were trying to wipe a window dry with a squeegee. You do this quickly, and lift it clear of the paper before the glue has time to set.

[EDIT] Here's a demonstration on squeegeeing a window...

[video=youtube;F9-zq6ptIBo]https://www.youtube.com/watch?v=F9-zq6ptIBo[/video]

[/EDIT]
 
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Major Tom

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Ok, that's what I was picturing. Seems like a good method to keep the glue uniform as well. I will give it a whirl on an Estes Crossfire ISX I am ready to paper this weekend. Thanks again.
 

Major Tom

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Worked perfectly. Even after prime and sanding the edges have not budged.
 

USAFmissileer

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I've always wondered what papering the fins was like. I hate sanding and filling. The smell, mess, an often unsatisfactory results. Great idea and tutorial! I have a mega mosquito I am itching to try thus on now! Thanks K'Tesh


Launching rockets (or missiles in my case) is so easy a chimp could do it. Read a step, do a step, eat a banana.

Sent from my iPad Air using Rocketry Forum.
 

PhlAsh

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I usually leave my edges square, glue the paper true to the root edge, then let the sanding knock off the excess paper
 

morlock

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Thanks for the short tutorial! I just finished papering my first fins for the Estes Bull Pup kit and it just turned out very well.

IMG_20140817_210158_small.jpg

Next time, I think I'll do like PhlAsh suggests and will paper them before I sand them to shape. H
 
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TopRamen

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Does the Glue Stick absorb into the Wood like TB II does to harden the Wood, or does it just adhere the Paper to the Surface of the Wood?
 

K'Tesh

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Does the Glue Stick absorb into the Wood like TB II does to harden the Wood, or does it just adhere the Paper to the Surface of the Wood?
I'd say adhere the paper to the wood surface.
 

morlock

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Does the Glue Stick absorb into the Wood like TB II does to harden the Wood, or does it just adhere the Paper to the Surface of the Wood?
I don't think it absorbs much into the wood, but since balsa by itself is already hard enough, I guess the little added strength is enough. From my little experience with the glue stick, it spreads very easily and there is low chance of creating a mess. I find spreading wood glue into a very thin layer is much more difficult and leaves everything around the work area semi-sticky, including my fingers, and creates much more chances of messing the fin.

How do you spread the wood glue into a very thing layer?
 

TopRamen

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I don't think it absorbs much into the wood, but since balsa by itself is already hard enough, I guess the little added strength is enough. From my little experience with the glue stick, it spreads very easily and there is low chance of creating a mess. I find spreading wood glue into a very thin layer is much more difficult and leaves everything around the work area semi-sticky, including my fingers, and creates much more chances of messing the fin.

How do you spread the wood glue into a very thing layer?
With my Finger. I keep a Wet Towel next to me on the Bench to wipe my Finger on as I work, so that I don't touch the Paper with Glue.
 

morlock

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With my Finger. I keep a Wet Towel next to me on the Bench to wipe my Finger on as I work, so that I don't touch the Paper with Glue.
Pretty high tech stuff! Hehe. I try to use at least one new technique per build, so I'll try the wood glue on a future project.
 

CzTeacherMan

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Interesting... I never heard of papering fins before this thread... I definitely think I'll give it a whirl. I just completed a Bull Pup, and the canard finds just look... Well, I'm not asking anyone to look too closely.
 

morlock

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Interesting... I never heard of papering fins before this thread... I definitely think I'll give it a whirl. I just completed a Bull Pup, and the canard finds just look... Well, I'm not asking anyone to look too closely.
Give it a try! It is super easy and the result is astounding. Plus, no more endless iterations of priming and sanding.
 

ThirstyBarbarian

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I had never tried papering fins, but now I'm building a Mega Der Red Max, and there is no way I wanted to sand all those acres of balsa. So I tried papering the fins with not such great success on my first try.

I used Manila file folders for the paper, and I tried the Elmer's All-Purpose glue stick. The paper is not large enough to completely wrap around the leading edge and do both sides with one piece, so I glued the paper on one side of the fin, wrapped around the leading edge and trailing edge, then cut the paper to the centerline of the edge. Then I tried the second side and wrapped and cut it the same way. Everything seemed fine except for the leading and trailing edges. The paper was loose there and peeling up. No matter what I did, it didn't seem to want to stick down as it wrapped around the airfoiled edges. So I peeled everything off and sanded it all back down. As I was peeling the paper off, it turned out that it really wasn't all that well bonded to the fin.

So now I am trying something different. I'm using the same file folder paper, but this time I'm using Elmer's Glue All white glue. I smeared a layer on and stuck the paper to the fin, wrapping around the leading and trailing edges to the center line, but leaving an inch or so of glue-coated paper overhanging. Then I glued the second side, also with paper overhanging as well. I pressed the glued faces of the overhanging paper together and clamped them together right up to the wood. It seems like the liquid glue is adhering better than the stick. And with both sides of paper glued together at the leading and trailing edges, the paper cannot peel away from the curve of the airfoil.

After everything dries, I'll trim the overhanging paper close to the leading and trailing edges and sand them smooth.

Papering definitely makes a nice smooth surface, but I have to say I had a few moments of panic when I decided I had to peel off the first effort! These MDRM fins are a lot of work, and I've made some modifications, so it's even MORE work! I was freaking out when I thought I had screwed them up!
 
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luke strawwalker

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I had never tried papering fins, but now I'm building a Mega Der Red Max, and there is no way I wanted to sand all those acres of balsa. So I tried papering the fins with not such great success on my first try.

I used Manila file folders for the paper, and I tried the Elmer's All-Purpose glue stick. The paper is not large enough to completely wrap around the leading edge and do both sides with one piece, so I glued the paper on one side of the fin, wrapped around the leading edge and trailing edge, then cut the paper to the centerline of the edge. Then I tried the second side and wrapped and cut it the same way. Everything seemed fine except for the leading and trailing edges. The paper was loose there and peeling up. No matter what I did, it didn't seem to want to stick down as it wrapped around the airfoiled edges. So I peeled everything off and sanded it all back down. As I was peeling the paper off, it turned out that it really wasn't all that well bonded to the fin.

So now I am trying something different. I'm using the same file folder paper, but this time I'm using Elmer's Glue All white glue. I smeared a layer on and stuck the paper to the fin, wrapping around the leading and trailing edges to the center line, but leaving an inch or so of glue-coated paper overhanging. Then I glued the second side, also with paper overhanging as well. I pressed the glued faces of the overhanging paper together and clamped them together right up to the wood. It seems like the liquid glue is adhering better than the stick. And with both sides of paper glued together at the leading and trailing edges, the paper cannot peel away from the curve of the airfoil.

After everything dries, I'll trim the overhanging paper close to the leading and trailing edges and sand them smooth.

Papering definitely makes a nice smooth surface, but I have to say I had a few moments of panic when I decided I had to peel off the first effort! These MDRM fins are a lot of work, and I've made some modifications, so it's even MORE work! I was freaking out when I thought I had screwed them up!
That's why I suggest regular printer paper and white glue spread in a very thin, uniform layer. Works like a champ. I detailed the process in my "Dr. Zooch Vanguard Eagle Beta Build" thread. Post 6 and following, with pictures and description... https://www.rocketryforum.com/showt...d-Eagle-Beta-Build-Thread&p=118648#post118648

Manila folder, cardstock (both 100 pound and 65 pound), and such ALL will work, BUT, the thicker and stiffer the paper is, the harder it is to apply. There was a thread around here somewhere (and over on YORF) about someone (can't remember who) using FREEZER PAPER to paper fins... it was coated with a plastic coating on one side, and was paper fiber on the other side. One just wants to make sure that any plastic coated side faces OUT, so that you're using white glue in its intended role to glue paper to the wood, on the exposed paper fiber surface, with the plastic surface facing out.

One can use regular freezer paper, in the big sheet rolls. Same methods should work just fine. Paper sacks also can be used, but the paper isn't as smooth or "hair free" (fibers of paper sticking up above the surface that require heavier priming and sanding to get rid of).

The thicker and stiffer the paper, the harder it will be to get it to conform to the fin and stay stuck down while it dries... when you cut it right next to a tight bend (like over the leading or trailing edge of the fin) you're practically guaranteed that it won't stay conformed down tight to the surface while drying... softer paper that is not so stiff should lay down and stay better.

Glue sticks really aren't that great an adhesive... a good white glue is MUCH better, and more permanent. I wouldn't trust a glue stick. They're fine for kiddie projects and maybe scrapbooking, but for something flying a couple hundred miles an hour through the air?? Not so much IMHO.

One other thing-- DO NOT forget to burnish the paper down tight to the surface. Squeeze as much glue as possible out from between the paper and wood... the less glue, the better the joint will be! That might sound counterintuitive, but when the molecules link directly to the paper on one end and the wood on the other, instead of in a daisy-chain fashion from the paper on one end, through any number of glue molecules connected end to end, and then to the wood, there's more chance of failure of the bond. This is a well understood property of glue. You only need enough to COMPLETELY and UNIFORMLY coat the surfaces so that they bond together. Any excess glue trapped in there just impedes the process... this is one of the problems with glue sticks and yellow wood glue-- its thicker, and therefore harder to squeeze out the excess glue. The other issue is, white glue (and yellow wood glue) uses water as a solvent. If too much glue is used, the excess water will draw into the paper through wicking up the fibers of the paper, softening it and causing it to "warp" or bubble up. A slight amount of warping or bubbling up when the glue is rubbed out onto the surface (I do it with a fingertip, to spread it as thinly and uniformly as possible) is okay-- it will lay down flat when the fin is pressed down against the paper. If the paper, however, has gotten TOO MUCH moisture in it from too much glue, it will soften and either wrinkle badly or even tear when being burnished down. This is a SURE sign of too much glue. It can be a fine line. That's why IMHO one is better off to use TOO LITTLE glue than TOO MUCH.

It takes a little practice... get some balsa scraps, some printer paper, and some white glue (all are cheap enough or free leftovers from kits) and practice, practice, practice...

Later and good luck! OL JR :)
 

7DeadlySins

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I just got a Estes Bull Pup in the mail from Amazon today...I think I might try papering the fins. Thanks for the tutorial(s) gents.
 

ThirstyBarbarian

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That's why I suggest regular printer paper and white glue spread in a very thin, uniform layer. Works like a champ. I detailed the process in my "Dr. Zooch Vanguard Eagle Beta Build" thread. Post 6 and following, with pictures and description... https://www.rocketryforum.com/showt...d-Eagle-Beta-Build-Thread&p=118648#post118648

Manila folder, cardstock (both 100 pound and 65 pound), and such ALL will work, BUT, the thicker and stiffer the paper is, the harder it is to apply. There was a thread around here somewhere (and over on YORF) about someone (can't remember who) using FREEZER PAPER to paper fins... it was coated with a plastic coating on one side, and was paper fiber on the other side. One just wants to make sure that any plastic coated side faces OUT, so that you're using white glue in its intended role to glue paper to the wood, on the exposed paper fiber surface, with the plastic surface facing out.

One can use regular freezer paper, in the big sheet rolls. Same methods should work just fine. Paper sacks also can be used, but the paper isn't as smooth or "hair free" (fibers of paper sticking up above the surface that require heavier priming and sanding to get rid of).

The thicker and stiffer the paper, the harder it will be to get it to conform to the fin and stay stuck down while it dries... when you cut it right next to a tight bend (like over the leading or trailing edge of the fin) you're practically guaranteed that it won't stay conformed down tight to the surface while drying... softer paper that is not so stiff should lay down and stay better.

Glue sticks really aren't that great an adhesive... a good white glue is MUCH better, and more permanent. I wouldn't trust a glue stick. They're fine for kiddie projects and maybe scrapbooking, but for something flying a couple hundred miles an hour through the air?? Not so much IMHO.

One other thing-- DO NOT forget to burnish the paper down tight to the surface. Squeeze as much glue as possible out from between the paper and wood... the less glue, the better the joint will be! That might sound counterintuitive, but when the molecules link directly to the paper on one end and the wood on the other, instead of in a daisy-chain fashion from the paper on one end, through any number of glue molecules connected end to end, and then to the wood, there's more chance of failure of the bond. This is a well understood property of glue. You only need enough to COMPLETELY and UNIFORMLY coat the surfaces so that they bond together. Any excess glue trapped in there just impedes the process... this is one of the problems with glue sticks and yellow wood glue-- its thicker, and therefore harder to squeeze out the excess glue. The other issue is, white glue (and yellow wood glue) uses water as a solvent. If too much glue is used, the excess water will draw into the paper through wicking up the fibers of the paper, softening it and causing it to "warp" or bubble up. A slight amount of warping or bubbling up when the glue is rubbed out onto the surface (I do it with a fingertip, to spread it as thinly and uniformly as possible) is okay-- it will lay down flat when the fin is pressed down against the paper. If the paper, however, has gotten TOO MUCH moisture in it from too much glue, it will soften and either wrinkle badly or even tear when being burnished down. This is a SURE sign of too much glue. It can be a fine line. That's why IMHO one is better off to use TOO LITTLE glue than TOO MUCH.

It takes a little practice... get some balsa scraps, some printer paper, and some white glue (all are cheap enough or free leftovers from kits) and practice, practice, practice...

Later and good luck! OL JR :)
I thought using the folder card stock would make the process easier than using thinner paper, but it was definitely part of the problem. The "spring" action of the card trying to straighten out where it curved around the airfoil was what was peeling the paper up at the edge. Thinner paper would have conformed better.

The liquid white glue worked much better that the glue stick. It was messier, but it worked better.

I used a Bondo spreader to force the bubbles out. And I've been letting the fins dry sandwiched between a cutting board and counter with some weight on top, the big flat surfaces should be pretty flat and smooth. Maybe I'll burnish the curved airfoil surfaces, although by now they may already be dry.
 

morlock

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I just got a Estes Bull Pup in the mail from Amazon today...I think I might try papering the fins. Thanks for the tutorial(s) gents.
I papered the fins of my Bull Pup recently using glue stick. Worked beautifully but now I am doing my scratch build with yellow glue.

Both worked fine. The process was easier with glue stick but the result probably is stronger with the yellow glue.
 

BABAR

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The liquid white glue worked much better that the glue stick. It was messier, but it worked better.
dry.
Spray adhesive goes on easily and evenly. I am guessing however that liquid glue probably provides more strength than glue stick or spray on
 

ThirstyBarbarian

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Spray adhesive goes on easily and evenly. I am guessing however that liquid glue probably provides more strength than glue stick or spray on
One of the things I was trying to accomplish was to strengthen the fins. For this project, I'm adding on to a Mega Der Red Max fin. The fins have an internal plywood frame, and an external balsa skin is glued to the outside of the frame. I had glued an additional piece of plywood frame onto the existing frame, edge to edge. It seemed like that would be a potentially weak joint. Adding the balsa skin over the whole frame and across that joint stiffened and strengthened it a lot. But I thought papering the entire fin would strengthen it even more. The white glue soaked into the fibers of the card stock and into the fibers of the balsa. I think it is really solid now. I don't have any worries the fin will break across that joint now.
 

ThirstyBarbarian

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In the end, I was really happy with how the fins turned out. By using the clamps to clamp the overhanging edges of card stock together right where the two glued sides meet at the centerline of the trailing and leading edges, the paper glued down nice and tight around the curve of the airfoil. After it dried, I used scissors to cut the excess overhanging material off to within about 1/16 to 1/8 inch of the fin edges.

Then I did the thin CA squeegee trick K'Tesh mentioned in the OP. I used wax paper set in the bottom of a shoe box lid to contain the CA and swiped the fin edge through it, saturating the edge and about 1/4 or so inches of the curving airfoil.

After the CA hardened. I sanded off the excess left over from trimming with a sanding block and blended it into the airfoil. The CA-soaked paper sanded really nicely. It left a nice sharp edge.

It worked out great!
 

Rex R

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two things I've noticed 1) balsa fins are much more forgiving than plywood when it comes to getting a smooth layer of glue, and 2) when you don't care about getting a nice smooth paper job the fins will turn out perfect :) (aerodynamics aren't a big concern when the rocket isn't likely to exceed 120mph)
Rex
 

75Grandville

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I decided to try the above method out, given that the fins on a Richter Recker are pretty big. I have to say that this method seems to have worked pretty well. Fins are being glued on, and all looks good. Just a couple of notes, for those trying this method, based on my limited experience:

  • Use CA in unventilated hotel rooms only with caution. :no:
  • If you are papering symmetric fins, be sure to mark which is the leading edge before you cover the grain.
  • This turned out much better than my initial attempt with yellow glue.
 

Kruegon

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OK. One thing I am a bit confused on. Does the paper wrap around the edges or just go to the edges? If it just goes to the edge, I would think it'd be better to shape the fins after papering them.

I'm assuming the ca is to seal the edge of the paper and the exposed edge of the balsa. The same way you seal your nosecones.
 
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