Papering fins, adhesive label paper vs glued on paper

[afadeev]

I already discovered that I have to apply the yellow glue to the balsa, not the paper, lest it start to wrinkle/get soggy immediately.

I've arrived at the opposite conclusion, net of dozen+ sets of papered fins.
Namely, apply TBII to the paper (regular printer paper stock ,or thicker), remove excess by finger, then apply to the fin core. Do both sides at once, then stick the finished product under something heavy (e.g.: cutting mat on my desk).

If you apply glue to the fin directly, much of it will get absorbed into balsa. This will warp the balsa as the glue dries, unless you somehow succeed in soaking-in identical quantities of glue to both sides of the fin.

YMMV.

And once pressed on to the balsa, that paper isn't going anywhere - even using a roller to smooth it out is dicey. Probably due to the learning curve, as expected.

If you had removed excess amount of glue from the paper before applying it to the fin, there wont be any need for a roller or a squeegee.
This can be tricky if you had printed a design on the outside of the paper, but doable.
Otherwise, just spread the wood glue (TBII) 1/8" beyond the fin outline on the paper, and the exact alignment wont matter.

How long should I let the fin dry before removing from under the stack of books. I was thinking a day or two.

Overnight works for me with TBII.
Once you start cutting paper overhands, you will know if the glue had dried fully, or the fin needs to go back under the mat for a bit longer.
Don't start sanding and CA-ing the edges until the glue is fully tried, else the edges may start tearing.

HTH

 

[BABAR]

I paper with white glue.

I apply the glue to the PAPER, squeegeeing as much glue off as I can with a hotel card, and I do BOTH sides (I also wrap around the lead, trail, and lateral edges, but that’s optional.

I use a throw away journal or magazine as a backing for my squeegee procedure. After each piece is squeegeed, I remove the paper and apply it to the fin, rip off the front page of the magazine and toss it, so I have a fresh page for the next one.

Apply the paper to the fin. You have to work quickly, the moisture in the glue will quickly soften the paper and it will tear easily. Get both sides covered, put it in a fold of waxed paper, and stick it in an old book, doesn’t hurt to put some weight on it.

Mine usually are dry over nite.

 

[neil_w]

What's the advantage of applying glue to the paper instead of the wood? When I've done it I put the glue on the wood.

 

[Scott_650]

I already discovered that I have to apply the yellow glue to the balsa, not the paper, lest it start to wrinkle/get soggy immediately. And once pressed on to the balsa, that paper isn't going anywhere - even using a roller to smooth it out is dicey. Probably due to the learning curve, as expected.

How long should I let the fin dry before removing from under the stack of books. I was thinking a day or two.

Believe it or not I’ve been using the much reviled Elmer’s School Glue to paper fins for a few years and much prefer it to white or yellow glue - thin layer on the fin surface, “squeegeed” smooth with an old credit card, paper layer on and again smoothed with an old card, immediately pressed between two Dollar Store cutting boards under a mountain of books - one side, then the other, minimal glue seems to keep warping from happening. My theory is the thinner, higher water content School Glue soaks into the wood and paper more thoroughly than regular white/yellow glue.

 

[BABAR]

What's the advantage of applying glue to the paper instead of the wood? When I've done it I put the glue on the wood.

In my case one side is cut the size of the fin, with tabs that will wrap around the lead, lateral, and trail edges. You need to get glue on ALL surfaces.

The second is cut just a bit SMALLER than the corresponding side.

You can go either way, put the tab piece on last, you will have some seams, but if you cut it right they actually look “real.” And they are small anyway. Or you can do the tabs first, and cover them with the slightly cut small second piece.

There is no trimming or sanding after the paper is applied.

 

[heada]

Take 40lb kraft paper, coat with universal wallpaper paste on both sides and then ball up and set aside. Apply a thin coat of the wallpaper paste on the fin. Then unball the kraft paper and recoat in wallpaper paste. Apply onto fin and sandwich between panes of glass with a few books on top. Balsa fins now have the strength of plywood. You can sand with 320 and then 400 to get a perfect finish. Kraft paper uses longer fibers than printer paper so it's stronger and using the wallpaper paste gives fiberglass/epoxy like matrix.

https://www.lowes.com/pd/Roman-PRO-543-128-oz-Liquid-Wallpaper-Adhesive/3034661
https://www.amazon.com/dp/B003U6OWZ0/ref=cm_sw_r_cp_apa_fab_gaoEFbYNH9MH3

 

[lakeroadster]

Believe it or not I’ve been using the much reviled Elmer’s School Glue to paper fins for a few years and much prefer it to white or yellow glue - thin layer on the fin surface, “squeegeed” smooth with an old credit card, paper layer on and again smoothed with an old card, immediately pressed between two Dollar Store cutting boards under a mountain of books - one side, then the other, minimal glue seems to keep warping from happening. My theory is the thinner, higher water content School Glue soaks into the wood and paper more thoroughly than regular white/yellow glue.

I also use Elmer's school glue... & a mountain of books.

How long should I let the fin dry before removing from under the stack of books. I was thinking a day or two.

Proceed with caution.

Since the papered fins were in wax paper, under the books, it makes drying difficult. Once released from the pressure and wax paper they will warp if not allowed to dry on both sides at an even rate.

When I remove the papered fins from the books I set them on a drying rack and add weights to keep them from warping / curling.



View attachment 433715

 

[lakeroadster]

How long should I let the fin dry before removing from under the stack of books. I was thinking a day or two.

Proceed with caution.

Since the papered fins were in wax paper, under the books, it makes drying difficult. Once released from the pressure and wax paper they will warp if not allowed to dry on both sides at an even rate.

When I remove the papered fins from the books I set them on a drying rack and add weights to keep them from warping / curling.





View attachment 433715

 

[Bill S]

Proceed with caution.

Since the papered fins were in wax paper, under the books, it makes drying difficult. Once released from the pressure and wax paper they will warp if not allowed to dry on both sides at an even rate.

When I remove the papered fins from the books I set them on a drying rack and add weights to keep them from warping / curling.

Thanks for the tip. That could have been what happened to me with my Super Big Bertha; I put pieces of Saran Wrap on both sides to keep the white glue from sticking to anything, and after a day or so I took the fins out and let them lay on the table, not realizing that they were going to warp because they hadn't fully dried yet.

I took the practice fin, put it between 2 metal drying racks with a couple books on top to keep the fins from warping (I hope). Hopefully tomorrow I will have a dried out fin that is ready to weigh/examine more closely.

 

[afadeev]

What's the advantage of applying glue to the paper instead of the wood? When I've done it I put the glue on the wood.

See post #31: https://www.rocketryforum.com/threa...l-paper-vs-glued-on-paper.161986/post-2050133

OK, I have time on my hands, and a dozen unspoken-for BMS school rockets with 4 (four) fins per each.
Time to structure and document a fin papering experiment.

What test variables do you want to be measured?
Finished weight?
Finished smoothness?
Ease and total time of prep?
Strength?

Prep variations under consideration:
1). Balsa fin grains filled with Elmers carpenter's wood filler (CWF)? Then a layer of primer, then paint?
2). Balsa fin grains filled with few coats of primer paint? Then a layer of paint?
3). Fins papered with glued-on (TBII) skins? Then a layer of paint?
4). Fins papered with stick-on adhesive labels skins?
5). Fins papered with glued-on epoxy (BSI 30 mins?) skins?

I only have 4 balsa fins, so which 1 of the 5 methods above gets an axe?
Is there another method that I should try instead?

a

 

[neil_w]

I'm not convinced #5 is a real thing.

 

[mbeels]

One advantage of using white glue is that you can iron out any warps. I apply white glue to the balsa, squeegee off as much as I can (it'll seem like there almost isn't any left), and then apply paper.

Then, I either:

1) Let it dry under a stack of books and weights. Then iron out any warps, bubbles, or wrinkles. The heat re-activates the PVA and you can get a fin totally flat this way.

2) Or go straight to iron while the glue is still wet. It will dry much faster, and you can get it flat, quickly.

 

[BABAR]

Mine seem to dry over nite, without any warping. But I use very little glue, it is almost all squeegeed off.

I’ll see your challenge. Looking at strength.

6 inch x 12 inch strips of 1/16” balsa.

Long axis WITH the grain.

2 each,
Raw balsa
Adhesive paper (both sides, genetic brand I have on hand— I tried to get Avery at Wally World today but they were out)
White glue standard copy paper, both sides.

All piece cut from same piece of balsa.

I will stick them on a table with one inch stuck under a book.

To start, move a 500 gram standard weight (I use it to zero my scale, my son saw the scale and thought I was dealing drugs!) starting from right next to the book and moving out to 11”, starting with the raw balsa (I figure that will break pretty quick.).

 

[BABAR]

 

[BABAR]

Cuts weren’t quite even, so I placed the stack on the side flat, and sanded until all were equal width

 

[BABAR]

My white glue

 

[Bill S]

I took the practice fin, put it between 2 metal drying racks with a couple books on top to keep the fins from warping (I hope). Hopefully tomorrow I will have a dried out fin that is ready to weigh/examine more closely.

Well crud. I apparently put a little too much weight on the fin; I had it sandwitched between 2 drying racks, and the upper rack left some minor indentations in the fin. Obviously I need less weight, but the fin is nice and straight. Good thing its a practice fin. I think I can putty it and sand smooth with some putty and sand the defects with some 800-grit sandpaper.

I'll keep tinkering with the process, as its quicker and lighter weight than the epoxy. That and I don't have to fool around with epoxy fillets (which I am not very good at yet). My final results, weight-wise:

Bare fin: .14oz
Bare fin+paper .19oz
Finished fin: .22oz
Half the weight of the epoxy fin, though there is still some flex in the balsa. Definitely not as stiff as the epoxy, though that could be a good thing.

 

[BABAR]

First pic
Glue Applied

Second pic
Glue squeegeed. You can see the gloss of the glue around the paper. As long as you are careful not to move the paper (not very hard) no glue gets on the current UNDERSURFACE (which will be the outer surface when applied.)

Third pic
Applied the paper to the fin. I like to recycle, AND i figured if I used paper with printing on it I would be less likely to confuse which balsa was glued versus adhesive papered.

Fourth pic
I use wax paper to burnish the paper into the balsa. You can press as hard as you want, rub back and forth and sideways, and you won’t tear the paper

Fifth pic
Wrap the glue-papered balsa in waxed paper and stick it in an old book

6Th pic

Shows the journal I used as backing when I squeegeed the glue, after I pulled the paper off. You can see the sheen where the glue outlines where the paper was, with no sheen in the location of the paper. Right after this, I rip this sheet off toss it and I have a new sheet for the next fin.

7 and 8 just more putting the balsa in the book

9. Just to keep things even, I also used waxed paper to burnish the adhesive paper into the balsa the same as I did the glued balsa. All pieces (raw, adhesive, and glue) I will put in the book for 24 hours. I will then take them out and weigh them. I will re-weigh the glued balsa 24 hours later to see if there is any more water loss, also see if it warps. My experience has been that just 12 hours overnite in wax paper and the book has been adequate, I think because I use VERY little glue (well, kinda like Neil and primer, I use a good bit but almost all of it is squeegeed out like he sands his primer.)

 

[BABAR]

That and I don't have to fool around with epoxy fillets (which I am not very good at yet). My final results, weight-wise:

though there is still some flex in the balsa. Definitely not as stiff as the epoxy, though that could be a good thing.

For paper to paper to wood and for wood to wood, wood glue is as strong as epoxy and much lighter. I was surprised when my Interceptor E instructions recommended epoxy for the balsa wood fins to paper tube joints, I am sticking with wood glue. I was also concerned that the instructions recommended epoxy fillets smoothed with an ungloved finger.

Make sure you wear gloves with that stuff. Since I build in the TV room with my wife and our yellow Labrador, Lucy, I stick (literally!) to relatively odorless glues like white, yellow, and CA. (Yup, living my teenage dream, climb into bed with two gorgeous blondes every night!)
If you “paper” with epoxy, I am not sure what glue would be the best. It the fin is smeared all around the attachment surface, probably epoxy.

I am surprised your balsa still flexes after Glue-papering, mine is usually like a rock.

 

[RobertH3]

I've been using yellow glue but like both the adhesive paper and Super77 ideas. The adhesive paper sounds great for LP builds and 1/16 warp-prone balsa.
I finished some car speakers with carpet and Super77 waaayyy back and it was awesome stuff. Yellow glue took considerable practice before I was comfortable with it and speed, correct amount, and perfect alignment are of the essence, and you often have to press them.

Cheers / Robert

 

[RobertH3]

I yellow glue papered my Int. E so I could get rid of the bracing balsa uglies, and used it for everything except the plastic. 15 min epoxy for that. With the TTW attachment it seems pretty bada**

Cheers / Robert

 

[BABAR]

Proceed with caution.

Since the papered fins were in wax paper, under the books, it makes drying difficult. Once released from the pressure and wax paper they will warp if not allowed to dry on both sides at an even rate.

When I remove the papered fins from the books I set them on a drying rack and add weights to keep them from warping / curling.

View attachment 433711



View attachment 433715

Regarding drying time in wax paper.

I put my fins in wax paper INSIDE a book. The book is the Physicians Desk Reference, used in pre-internet days to keep track of all (or most all) available drugs. A key issue is the pages are NON-glossy paper. This may be why my fins dry relatively quickly (usually overnight) in waxed paper INSIDE the book, even without air circulation.

 

[dhbarr]

Regarding drying time in wax paper.

I put my fins in wax paper INSIDE a book. The book is the Physicians Desk Reference, used in pre-internet days to keep track of all (or most all) available drugs. A key issue is the pages are NON-glossy paper. This may be why my fins dry relatively quickly (usually overnight) in waxed paper INSIDE the book, even without air circulation.

Yup, the water's going into all those other pages.

 

[BABAR]

Yup, the water's going into all those other pages.

Which is why I say use an old throw away book! That’s from 2008

 

[BABAR]

I yellow glue papered my Int. E so I could get rid of the bracing balsa uglies, and used it for everything except the plastic. 15 min epoxy for that. With the TTW attachment it seems pretty bada**

Cheers / Robert

I like white rather than yellow glue for papering for two reasons.

The most obvious, it dries white or clear, so I don’t have to worry about the color (not a big deal, I’m pretty sure most primers cover over any yellow from the paint anyway.)

Yellow glue “grabs” faster than white. Which is great for sticking fins on. For papering, if I don’t get alignment perfect right off, the white gives me a little more maneuvering time. Not much, because once it soaks into the paper the paper tears easily. I also use white glue when placing motor mounts in my LPR birds, I don’t have to worry as much about getting the “pusher” casing stuck. You still have to be pretty quick.

 

[neil_w]

Yellow glue “grabs” faster than white. Which is great for sticking fins on. For papering, if I don’t get alignment perfect right off, the white gives me a little more maneuvering time. Not much, because once it soaks into the paper the paper tears easily. I also use white glue when placing motor mounts in my LPR birds, I don’t have to worry as much about getting the “pusher” casing stuck. You still have to be pretty quick.

Score one for not precisely pre-cutting the paper. I just slap on an oversized piece and sand off the excess afterwards, which with office paper takes seconds.

BTW I've found that glued office paper does conform to the grooves of the wood a bit, so it still benefits from a coating of filler/primer afterwards to even it out. Not so with label paper (or cardstock, I would assume) which stays absolutely flat.

Nice to have options.

Maybe one day I'll make a video of my label papering process. Would that be of interest to anyone?

 

[BABAR]

Video would be cool.

 

[neil_w]

I'll need to figure out how to rig up the camera. Could be fun, will post when/if I am able to do it.

 

[afadeev]

I'm not convinced #5 is a real thing.

Perhaps.
I've just remembered (6). CA soaking balsa fins. I used that once on super-think balsa for a helicopter rocket.
Given that I'm upto 6 scenarios, and it's not my thread, I will unbox another School rocket kit and make it 6 sample fins, and kick off a new thread for my comparison:
https://www.rocketryforum.com/threa...ues-methods-documenting-pros-and-cons.162097/

For paper to paper to wood and for wood to wood, wood glue is as strong as epoxy and much lighter.

Yes, plus wood glues are MUCH easier to work with, easier to cleanup with paper towels, and are non-toxic.
It's pretty much the Epoxy.

Epoxies do work well with more materials, and don't shrink while solidifying, which is is a big plus when laying fin fillets.

I was surprised when my Interceptor E instructions recommended epoxy for the balsa wood fins to paper tube joints, I am sticking with wood glue. I was also concerned that the instructions recommended epoxy fillets smoothed with an ungloved finger.

Good luck with wood glue fillets. I never could get mine to level and shrink evenly. Even TB Quick & Thick shrinks on me.
I am gluing my fillets with TBII, but using epoxy for fillets.

I am surprised your balsa still flexes after Glue-papering, mine is usually like a rock.

Agreed.
Same here.

 

[heada]

Test spray on adhesive such as 3M 77 (or 90 if you have it)