Homemade Decals and Fin Strengthening

[BPRescue]

Hi All,

Dang Novice; haven’t even completed one rocket and I am already thinking of unconventional (at least in my own mind) ideas to change it up and or make it better.

The first item I found was just perusing youtube for basic building strategy. I found this link, that intrigued me and though I agree it will make the balsa fins stronger, also cutting out some time of filling/sealing for that perfect finish, I have a few concerns about durability and finishing. First of all; clearly you have to get just enough glue, otherwise you just wasted a nice fin be it failing paper adhesion especially at the edges.corners , or lack of uniformity. I imagine even thinning the glue with a drop or two of water will help give a few extra seconds of work time. Even a simple squeegee of sorts to spread the glue vs. using your imperfect finger, but again you would have to be perfect and not remove the glue. Another item, is once it is dry, will the paper accept paint well and be durable? Finally, I can imagine any ding during usage will render the paper pealing; but nothing a little CA can’t resolve if you catch it before it starts to peel the weak paper; paint should help. I imagine one could choose a durable paper as well which would resolve the failure of the paper itself; clearly the yellow glue will be perfect for paper to wood. Either way, I can see great benefit to a plywood theory that really does strengthen the wood, but is it feasible? Anyone try this? I just may give this a shot on my BDay party big bertha project since it is disposable anyway…
http://www.youtube.com/watch?v=JnYBSbYr8ZE

Secondly, I am a bit of a freak. Not happy with professional photographers, I do all my own photos, Christmas cards, you name it, if I can put my stamp on it, I will. Also too cheap to pay people to build/design my yard, or even components of my house, and I don’t like their lack of quality, so I do it. So, it is no surprise that I am considering making my own decals with a USAF theme for Big Bertha, even assigning serial numbers of my son’s name/bday (told you..) Anyway, understanding inkjets will not work here unless I get a thin clear top layer to protect the ink from moisture, I have access to a color laser, so problem solved. They are matte full page labels that I would cut. My thought was to place on the already painted (enamel/krylon) rocket, then hit with a light coat of lacquer to give it a nice seal. Will be testing the bleeding of toner first obviously. Anyone try this?

Anyway, I have already learned not to trust my local hobby shop, as they already gave me some poor advice and luckily I tested before I followed through. I know the advice I get here will be good…

Thanks again.

[luke strawwalker]

I've seen Tim's video on this, and there is a MUCH easier and better way to paper fins... I do it all the time and it's a TERRIFIC timesaver that REALLY strengthens the fins and makes them about as "bulletproof" as anything made out of balsa can be!

Cut your fins out of the balsa sheet (or pop them out if they're pre-cut kit fins) and stack sand them til they're identical in shape. Sand in any airfoiling you want (round leading edge, tapered trailing edge standard airfoil, wedge shaped for scalers (usually) or whatever) just like you would for regular fins ready to glue on the rocket if you were doing it "the regular way" with sanding sealer...

http://www.oldrocketforum.com/attachment.php?attachmentid=21812&stc=1

Once you have the fins sanded to the final shape you want, grab a couple sheets of printer paper. Regular 20 pound printer paper will work just fine... It doesn't HAVE to be any special paper or heavy cardstock (though you CAN use that if you WANT to, but basically all it adds is weight, though Mark II on TRF has tried using the Reynold's Wrap Freezer Paper that has a slick coating on one side and really likes it, but I haven't tried it yet myself). Anyway, lay your printer paper out flat on your work mat.

http://www.oldrocketforum.com/attachment.php?attachmentid=21813&stc=1

Lay the fin flat on the paper, with the LEADING EDGE of the fin toward the center of the paper. Using a pencil, make a light outline of the fin onto the paper. Now, FOLD THE FIN OVER IT'S LEADING EDGE onto the paper so the fin is 'upside down' on the paper,and gently outline it again. You should have two outlines spaced apart a little bit. If the fin slips while you roll it over, do it again so the fin doesn't slip.

http://www.oldrocketforum.com/attachment.php?attachmentid=21814&stc=1

Take a fin, and using WHITE GLUE (white glues like Elmer's Glue-All is better for this joint, NOT yellow wood glues which are better for wood/wood joints-- white glue shrinks less and gives better working times). Smear a THIN even layer of glue over the top surface of the fin-- it doesn't have to be perfect, just make sure the fin's top surface is COMPLETELY covered with a THIN uniform layer of glue.
http://www.oldrocketforum.com/attachment.php?attachmentid=21815&stc=1

Now, flip the fin and line it up over the appropriate side outline of the fin, and press it down onto the paper. Press the fin down firmly against the paper. Now apply another THIN even layer of glue to the remaining top side of the fin, duplicating the first side, maybe just a TOUCH more glue (but don't go crazy with the glue-- actually LESS IS MORE in this application-- the thinner glue joint is stronger than a thick layer of glue, and a thick layer of glue can take a LONG time to dry and CAN wrinkle the paper if it's TOO thick!) Once you've got a nice thin uniform layer of glue applied to the whole fin surface, ROLL THE FIN OVER THE LEADING EDGE, keeping the paper taut, and press down the remaining side of the fin tightly against the paper.

http://www.oldrocketforum.com/attachment.php?attachmentid=21816&stc=1

More to come in Part II... OL JR :)

[luke strawwalker]

Continued from part I...

NOW, using a Sharpie marker or something similar (Sharpie markers work WONDERFULLY for this-- they're the perfect size, have a smooth rounded barrel end, and they're readily available) you need to BURNISH the paper down to the balsa wood. Start by laying the sharpie FLAT on the surface of the fin, so the round barrel lays on top of the fin, and starting from the front center of the leading edge, start sliding the pen towards the rear edge of the fin, and toward the tip and root edges of the fin... you can either slide the pen or use it like a 'rolling pin' is used to flatten out dough in the kitchen. This will squeeze all the excess glue out from between the paper and balsa, and make the strongest, smoothest joint between the two. This excess glue will also make sure that the paper has a GOOD STRONG JOINT between the paper and fin over the ENTIRE SURFACE of the fin, and espeically around the edges.
http://www.oldrocketforum.com/attachment.php?attachmentid=21817&stc=1

Work the glue from the center of the leading edge of the fin to both ends of the leading edge of the fin, at the root and tip edges. Also work the glue out by rolling the pen over the TRAILING edge of the fin, gluing the paper to itself. Take the round end of the pen, and go around the edges of the fin-- the pen will cause the paper to "stretch" over the edge of the fin and make it drum-tight, and glue it to itself. Flip the fin over and repeat with the other side.
http://www.oldrocketforum.com/attachment.php?attachmentid=21818&stc=1

When you're done, cut the fin out with about a half-inch of paper sticking out from the edges of the fin (root, trailing, and tip edges-- the paper is rolled tightly over the leading edge so it's already done!) and set it aside to dry. It only takes a couple minutes to do each fin-- less time than it took to read this!
http://www.oldrocketforum.com/attachment.php?attachmentid=21819&stc=1

Here are the fins for a two-stage Dr. Zooch Vanguard Eagle, all papered and set aside to dry... overnight is best. They'll be ready for trimming in the morning and ready to glue on the rocket.
http://www.oldrocketforum.com/attachment.php?attachmentid=21820&stc=1

Once dry, they're ready for final trimming. You can start by cutting off the excess paper around the edges of the fins with scissors, down to within about 1/4 inch or so of the fin edges themselves. Then, using your X-acto hobby knife with a SHARP (new) blade, carefully SHAVE the paper off the edges of the root and tip edges of the fin down to the surface of the balsa. Shave the paper off the trailing edge as close as you can without actually exposing the balsa (if you can, if not, it's ok-- if you can't see the balsa, the paper is glued tightly to itself, if you shave down to the balsa, the paper is still glued to the fin itself) This may take a few passes, and doing each side individually. Maybe 5 minutes per fin to shave them down.
http://www.oldrocketforum.com/attachment.php?attachmentid=21821&stc=1

More in Part III... OL JR :)

[luke strawwalker]

Cont'd from Part II...

Carefully shave the paper down to the balsa edges of the fin. This will also remove any excess dried glue that was squeezed out by the burnishing of the fin with the Sharpie marker...
http://www.oldrocketforum.com/attachment.php?attachmentid=21822&stc=1

You'll probably notice a few fuzzies around the edges... we'll take care of that in a minute-- the idea is to just get rid of ALL the excess paper down to the edge of the balsa.
http://www.oldrocketforum.com/attachment.php?attachmentid=21823&stc=1

Ok, so now we'll get rid of the fuzzies. Take a piece of 240 grit sandpaper, and lay it flat on your work mat. Take the fin, and put the root, tip, or trailing edge flat against the sandpaper, lean it over a couple degrees, and GENTLY DRAW the fin toward you.
http://www.oldrocketforum.com/attachment.php?attachmentid=21824&stc=1

The sandpaper grit will neatly shave off the last few remaining "paper hairs" and leave the edge of the fin pristine and sharp, with the paper glued PERFECTLY to the entire surface of the fin.
http://www.oldrocketforum.com/attachment.php?attachmentid=21825&stc=1

The leading edge is already done for you, so you only have to do the root, tip, and trailing edges!
http://www.oldrocketforum.com/attachment.php?attachmentid=21826&stc=1

Cont'd in Part IV... OL JR :)

[luke strawwalker]

Cont'd from Part III...

Here you can see the finished result after the final sandpaper shaving... it only takes a minute or two for each fin to do the final sandpaper shaving.
http://www.oldrocketforum.com/attachment.php?attachmentid=21827&stc=1

The root edge of the fin is perfectly flat and ready to glue on the rocket with a DOUBLE GLUE JOINT... (which is THE best way to put fins on a rocket, IMHO... all the convenience of CA "instant joints" without the brittleness and low shear strength of CA, with all the benefits of the strength of yellow wood glue joints, without the long clamp times waiting for yellow glue to 'grab' and hold the fin... Easy to do , too-- just apply a thin layer of yellow glue to the root edge of the fin, and set it aside to dry. Sand the glassine on the body tube lightly with 240 grit to take the shine off the tube, and apply a thin layer of glue to the tube where the fins will go... set it aside to dry, which takes maybe ten minutes. Take the fin, apply ANOTHER thin layer of glue to the root edge, carefully align the fin with the fin line on the tube, and the press the fin in place. Hold 20-30 seconds or so, and VOILA!-- the fin is glued onto the tube about like magic, ready for fillets! I usually give the fin a light fillet with yellow wood glue (sometimes just smear out the glue squeezed out from between the fin and tube while I press the fin on a few seconds waiting for the glue to 'grab'... or add just a LITTLE yellow glue if not much squeezes out, then after it's dried thorougly, I finish fillet with Titebond Moulding and Trim Glue, which is a thickened type of white glue, that won't run, sag, shrink, or end up with bubbles and holes in it like yellow glue does, making PERFECT fillets ready for paint, and it dries clear! )
http://www.oldrocketforum.com/attachment.php?attachmentid=21828&stc=1

Here are the finished fins... four for the first stage and four for the upper stage...
http://www.oldrocketforum.com/attachment.php?attachmentid=21829&stc=1

And here's the finished product... The fins need NO further finishing after the paper is applied-- they're ready for standard priming/painting. This rocket got a couple coats of Wal-Mart Colorplace 99 cent primer, a sanding with 400 grit, followed by a sanding with 600 grit wet/dry paper dipped in water, with the excess water shaken off, using a damp paper towel to wipe off the 'sanding mud' created by the wet sanding dust, then got a couple coats of WalMart Colorplace 99 cent flat white, with the fins painted by hand with a brush with Testors flat black... the rocket was too hard to mask to spray paint the fins... at least with the materials I had available...
http://www.oldrocketforum.com/attachment.php?attachmentid=21830&stc=1

Here's the overall rocket, sitting on the launch pad for the glamour pics....
http://www.oldrocketforum.com/attachment.php?attachmentid=21831&stc=1

I like doing it this way, but there are always more than one way to skin a cat... some folks prefer using Avery self-adhesive label paper applied to the fins and trimmed down, or using the Avery label paper with carefully cut out skins like Tim used in his Apogee Rocket Workshop video you linked to... I prefer this method for a couple reasons-- 1) it's cheap-- regular 20 pound printer paper from Walmart, nabbed out of the computer printer... 2) it covers the leading edge, so the paper can't come loose from the fin because of the slipstream of air ripping over the fin in powered flight at 200 mph+, because the paper is ONE SOLID PIECE completely covering the leading edge all the way back to the trailing edge... (folks who use label paper often have to go over the fin edges with CA glue to ensure the paper stays stuck down). 3) It's STRONG! How strong, you ask?? Well, I had the upperstage of this rocket go unstable on me (my fault) and power-prang into the ground almost horizontal at a HIGH rate of speed-- it hit the ground fin-first onto HARD dry packed Texas gumbo clay (like concrete) and the fin tip corner at the leading edge was partially demolished (last 1/4 inch of the tip) but the rest of the fin was perfectly intact; the fin sheared off the model, but it took the glassine and outer paper layer of tube with it to the edge of the fillets-- the glue joint itself didn't fail, and the impact damage to the fin was amazingly light considering the speed and force of the impact to the fin tip with the ground-- and there was hard clay stuck to the edge of the fin around the damaged tip, so it REALLY dug in there!

SO, no "special" stuff is required to do this, beyond what you have already-- typing paper, white glue, your hobby knife, and some sandpaper, and a little time and effort. Try it, you'll like it... sure beats Carpenter's Wood FIller!

Good luck! OL JR :)

[luke strawwalker]

(snip)

So, it is no surprise that I am considering making my own decals with a USAF theme for Big Bertha, even assigning serial numbers of my son’s name/bday (told you..) Anyway, understanding inkjets will not work here unless I get a thin clear top layer to protect the ink from moisture, I have access to a color laser, so problem solved. They are matte full page labels that I would cut. My thought was to place on the already painted (enamel/krylon) rocket, then hit with a light coat of lacquer to give it a nice seal. Will be testing the bleeding of toner first obviously. Anyone try this?

Anyway, I have already learned not to trust my local hobby shop, as they already gave me some poor advice and luckily I tested before I followed through. I know the advice I get here will be good…

Thanks again.

One thing-- DO NOT apply a lacquer over an enamel paint-- it will melt/craze the enamel paint and TOTALLY ruin your paint job!!! You can apply an enamel over the lacquer, but NOT the other way around! Lacquers use a "hotter" solvent than enamels, and the solvent will attack and wrinkle the enamel finish. Always do a 'spray test' first to ensure the compatibilities of the paints your using before applying different materials over each other...

Testor's makes a decal paper you can get at Hobby Lobby, or there are SEVERAL vendors online that sell decal paper, and at a better cost than the Testor's setup... inkjet printers are fine (not sure if the paper is even compatible with laser printers, actually-- you'd have to check on that) because you spray on a sealer/clearcoat to the decal paper before you cut it out to ensure that the inks are protected from moisture before you apply them... and of course you can always go over them again with a clearcoat after the decals are on the rocket and it's finished...

Later and good luck! OL JR :)

[BPRescue]

This forum continues to amaze me with the knowledge and responses received. I only hope I can offer a tenth of what you guys are providing for me. Thank you for the detailed and clearly time consuming replies.

I just returned, so I have not had a chance to read beyond the first reply, but just had to respond... Thanks Luke.

[barone]

The Testor Decal Paper (which I bought at Hobby Lobby using a 40% off coupon... ;) ) instructions say "Remember to use Water Slide Decal Paper with inkjet printers only."

[Gus]

Nice long thread on the topic of papering fins can be read here. (http://forums.rocketshoppe.com/showthread.php?t=1254)

[mikeyd]

The Testor Decal Paper (which I bought at Hobby Lobby using a 40% off coupon... ;) ) instructions say "Remember to use Water Slide Decal Paper with inkjet printers only."

I have used the Testors Decal paper, and it works ok, but remember that inkjet printer ink is not solid, it is translucent, meaning you can see through it. On the white decal paper this is not a problem, but all areas of the decal would have to be colored, including the background, if using on anything other than a white rocket. Note on the last picture, you can see the gray background of the decal on the silver rocket.

[AcroRay]

Thanks for the detailed run-down of your fin-papering technique, Luke!

I think I'll use that on my Estes BullPup this spring. :D Seems like a good rocket to test it on.

[ScaleNut]

I just laminate balsa sheet with 3m spray and printer paper.
When I need some fins I just cut them from that.
I got a pile of laminated balsa sheets and scraps.

I don't like using a glue thats made to shrink for laminating.

[jamjammer53150]

Ten thoundsanths Styrene can be used as well with contact cement

[mojo1986]

Consider trying tissue paper to cover your balsa fins. Tissue paper offers some advantages over printer paper...................

It's lighter.

It's very flexible, and conforms to the fin surface better than printer paper. You can even cover some surfaces with minor compound curves, like fins that are tapered in two axes.

It's so thin, it doesn't require 'filling' or any other particular treatment at its edge (i.e. where it terminates).

It's readily sandable. Not so for thicker papers like printer paper which leaves a furry edge when sanded and requires further finishing.

It won't lift from the fin two years from now...............label paper is prone to doing this.

I apply it to the fin with thin CA. This method is guaranteed NOT TO WARP THE FIN.

It comes in many colors. This is nice in situations where you want color but are reluctant to paint due to the added weight (gliders).

You can sand the fins before applying tissue paper, or wait and sand them after application. I like to work some yellow glue into the root edge and along about 1/8" of the sides at the root (for the fillet) before starting the papering job.

Joe

[jamjammer53150]

Okso we have
Printer paper
Tissue paper
Styrene


Or , just cut them out of plywood , somthing i have taken to doing on anything i intend on flying more than once , and i have yet to push anything over the edge weight wise ( and it is a good excuse to buy a JigSaw)

[luke strawwalker]

This forum continues to amaze me with the knowledge and responses received. I only hope I can offer a tenth of what you guys are providing for me. Thank you for the detailed and clearly time consuming replies.

I just returned, so I have not had a chance to read beyond the first reply, but just had to respond... Thanks Luke.

You're welcome...

You'd be surprised how many times this question has come up, both here and on TRF... I've answered it so many times that I took pictures during a build last summer just to detail the process...

Maybe someone will make it a "sticky" in building techniques or something... :)

As I said, there are other ways to skin a cat (Avery label paper) but I find this method cheapest and easiest with the best results... your mileage may vary... YMMV... LOL:)

Later and good luck! OL JR :)

[luke strawwalker]

I have used the Testors Decal paper, and it works ok, but remember that inkjet printer ink is not solid, it is translucent, meaning you can see through it. On the white decal paper this is not a problem, but all areas of the decal would have to be colored, including the background, if using on anything other than a white rocket. Note on the last picture, you can see the gray background of the decal on the silver rocket.

Luv ur Goonies...

L8r... OL JR :)

[John Brohm]

Consider trying tissue paper to cover your balsa fins. ...................

...

Joe

I have to agree; I am a committed SilkSpan and Nitrate dope devotee. Always will be.

[mojo1986]

I have to agree; I am a committed SilkSpan and Nitrate dope devotee. Always will be.

John, as stated, I use CA....................how is the long term adhesion with nitrate dope? I would prefer to use dope over CA if the adhesion is as good. Also, I have plenty of butyrate dope on hand but no nitrate.................care to speculate on whether there would be a difference in adhesion?

Joe

[John Brohm]

John, as stated, I use CA....................how is the long term adhesion with nitrate dope? I would prefer to use dope over CA if the adhesion is as good. Also, I have plenty of butyrate dope on hand but no nitrate.................care to speculate on whether there would be a difference in adhesion?

Joe

Happy New Year, Joe!

My experience with long term adhesion hasn't been an issue; the set is permanent.

There are several reasons why I prefer this method, keeping in mind that it's my preference. There's just about as many methods to finish as there are modelers; they can all deliver excellent results when mastered. So I have no interest in Finishing Religion wars.

With this caveat in place, here's why (for me):

- I like to minimize dust in my shop. Lord knows there's enough created by balsa, I don't need to add to it with FnF dust or Sanding sealer dust (although I must admit Sanding Sealer is my preferred method for balsa nose cones).

- I'm an old stick and tissue guy; very comfortable with the regime.

- My shop is far enough away from my wife that the generated fragrance is never an issue.

- Nitrate versus Butyrate: Nitrate has more solids content than Butryate, and it shrinks far less. Less shrinkage means less risk of warpage, especially important with thin fins.

- As mentioned, there has never been an issue with adhesion.

- Nitrate, once cured, is an acceptable base for just about any kind or type of paint - enamel, lacquer, acrylic, etc. I have never had a compatibility problem using Nitrate as a base.

- Finally, I have a severe respiratory reaction to the fumes from CA as it cures; the only CA I can use in my shop is the odorless kind, which means I get to pay about twice the going rate. So in my case I have to use CA pretty much for putting things together; I can't really afford to use it as a finish material.

Hope this helps;

[mojo1986]

Thanks, John. Happy New Year to you, too! I will definitely modify my method to give dope a try with the tissue paper. I also have problems with CA fumes, and I never seem to be able to get through a complete set of fins without sticking my fingers together. But I'll try butyrate first, since I have a lifetime supply of that. I'm not too worried about shinkage with butyrate because I will squeegee the tissue paper over it so that it will be a very thin layer, with equal layer thickness on both sides of the fin.

I was really glad to see that someone else uses tissue paper, by the way. I was starting to feel like a real loner!

Joe

[Solomoriah]

Regarding laser decal paper... I got some. The toner doesn't adhere to it perfectly; you have to handle it carefully, and clearcoat it at your first opportunity. Even so, some of my decals come out unusable.

I buffed the loose toner off one particularly bad sheet, printed text and graphics reversed on the back (paper) side, then painted the decal side. When cut out on the lines on the back (a bit tedious in some cases), you get a pretty cool result:

http://rocketry.gonnerman.org/fleet/groovyman.jpg

[John Brohm]

... I'm not too worried about shrinkage with butyrate because I will squeegee the tissue paper over it so that it will be a very thin layer, with equal layer thickness on both sides of the fin.

I was really glad to see that someone else uses tissue paper, by the way. I was starting to feel like a real loner!

Joe

Hi Joe;

When I apply SilkSpan to a fin I lay it flat and dry on top of the fin side, and then brush the dope through the SilkSpan, essentially using the dope to "glue" the SilkSpan to the fin. SilkSpan (and most airplane tissues, for that matter) are fairly porous, so this method works well and quickly.

Two more coats, with #320 grit sanding in between, usually leaves a fin ready for primer. Let me know how your squeegee method turns out.

[kurtschachner]

I found that this was highly dependent on the printer. Some (including most color copiers) adhere very well while others (some HP color laser printers) don't stick at all.

Way back in the late 90's a Kinko's about 20 miles from my house had some old color copier that made fantastic decals. The toner was put down thick and adhered like glue. It was awesome. Alas though, they got rid of that particular copier as an "improvement" for the store, and that ruined it. I still have some decals made from that copier though.


Regarding laser decal paper... I got some. The toner doesn't adhere to it perfectly; you have to handle it carefully, and clearcoat it at your first opportunity. Even so, some of my decals come out unusable.

I buffed the loose toner off one particularly bad sheet, printed text and graphics reversed on the back (paper) side, then painted the decal side. When cut out on the lines on the back (a bit tedious in some cases), you get a pretty cool result:

[Mark II]

[...]Once you have the fins sanded to the final shape you want, grab a couple sheets of printer paper. Regular 20 pound printer paper will work just fine... It doesn't HAVE to be any special paper or heavy cardstock (though you CAN use that if you WANT to, but basically all it adds is weight, though Mark II on TRF has tried using the Reynold's Wrap Freezer Paper that has a slick coating on one side and really likes it, but I haven't tried it yet myself).[...]I like the results that I get from it, but certainly there are many other methods that can be used successfully. Mine is just one.

One thing that was mentioned later on in the thread by another poster was using CA to bond tissue paper (so-called Japanese tissue?) to balsa. I have never had anything approaching success with using thin CA to bond anything onto wood. It is not meant to be used on rough-textured surfaces or porous surfaces to begin with, and in my experience it soaks right through the paper and into the wood without forming any kind of useful bond.

I have to agree; I am a committed SilkSpan and Nitrate dope devotee. Always will be.I would really like to try that technique. What has kept me from it so far is the fact that the materials are not readily available in my area, and ordering them online requires a bit of an investment.

I find that for small balsa fins, sealing and filling them with several layers of dope-based balsa fillercoat and sanding sealer actually imparts a fair amount of strength to the wood. The benefit is much greater than I would have expected, and it adds practically no weight.

[Mark II]

Ten thoundsanths Styrene can be used as well with contact cementI have thought of that, too. Again, for me, supply is the issue. Even very thin styrene is appreciably heavier than a comparable layer of paper, though, but with large fins (which is most likely where one would use this technique) the enhanced strength would probably make up for the increased weight. A thin layer of styrene on each side might be especially helpful in preventing the wood in a fin from splitting.

One of the most robust ways that I know of to strengthen and stiffen balsa fins without adding a different material is to laminate several thin layers of the wood together to create the desired thickness, rather than buying balsa in that thickness. For practical purposes, 3/32" is the thinnest balsa fin material that can be created with this method. (A sheet of 1/16" balsa that has been created by laminating together two sheets of 1/32" balsa will not have enough extra strength over just plain 1/16" balsa to be worth the effort.) The trick is to orient each layer so that its grain runs more or less perpendicular to the grain of the next sheet. For 3/32" material, I position the second layer so that its grain is oriented 45° to the first layer, and then position the third layer so that its grain is 90° to that of the first layer. What this creates is essentially balsa plywood. With this material, you don't have to worry about aligning the leading edge of your fin with the grain of the wood, because the wood is equally strong in all directions and is very resistant to splitting along any single grain.

[Mark II]

Don't discount the possibility of using thicker balsa, though. It is not practical or aesthetically pleasing to use thick balsa in all situations, but balsa in thicknesses greater than 1/8" is surprisingly stiff and strong. The particular size and shape of the fin plays a big part in this, but I have used 1/8" balsa on rockets that fly on E and F motors, and I wouldn't hesitate to use 3/16" or 1/4" balsa (plank balsa) on certain rockets that would be launched on F and even G motors.