Fin Reinforcement

I want to reinforce the fins on my Eliminator, my Storm Tracker, and maybe my Zenith II. (I did my first Zenith II and liked it.)

I plan to paper the fins. I've seen recommendations for spray adhesives (like the Super 77 I've used before) or for wood glue with the fins pressed while the glue dries.

Question: How does the glue dry with the fins pressed between waxed paper, does the waxed paper tend to stick anyway, etc.?

I don't want to use epoxy for this because I don't want to add significant weight.

Is CA any good for this purpose? Thick? Thin?

What are your favorite techniques, papers, etc.?

Thanks.

I haven't reinforced fins like you are describing.

So, that said -

I do know that CA (superglue) doesn't stick very well (if at all) to wax paper. If you slather something with CA and press it between sheets of wax paper, the wax paper *should* peel off relatively easily. At least, that has been my experience in other applications with CA.

Your mileage my vary.

Definitely something to try out first. Gread if it works for me.

Does CA cure properly if the fumes are constrained like that? Do they escape anyway? Hmmm. Easy to try on scrap.

I use 3m 77 and printer paper
it works well but epoxy would be stronger

I laminate using 3M spray adhesive and printer paper, similar to Stymye. After allowing to dry under some heavy books, I then seal the edges (except for the root) with thin CA.

Has worked pretty well so far...

I use a similar method to Bill, but I use white glue instead of the spray adhesive. I let it sit for a day or so under a stack of encyclopedias: https://www.rocketryforum.com/attachment.php?s=&postid=260809
Reed

I used the 3M spray and printer paper for my Zenith II, but I lapped the paper over the leading edge, and it wasn't the smoothest job. I think I could do a neater job next time.

I may try the wood glue, as it's not as messy as the 3M spray to use. I may also use aircraft tissue paper because it's thinner.

Since wood glue will soak through the paper, unlike the 3M spray, what is used to make sure it doesn't bond to the enclyopedias (or whatever)? I don't have glass sheets handy, and waxed paper soaks up moisture after a while.

Edit: One-letter typo fixed.

The waxed paper does soak up some moisture but, in the ~20hours I had the fins under the encyclopedias, the encyclopedias did not get glued to anything. If you aren't sure it will work, you can always put two layers of wax paper between the fins and encyclopedia instead of one.
Reed

I've been extremely pleased with the ease of use and strength of adhesive backed paper, 40lb. The glue on the paper I use is very strong, bonds hard to a well sanded fin. No glues to worry about.

Oh, if you try this, buy MATTE paper, not glossy.

Originally posted by JBeau
I've been extremely pleased with the ease of use and strength of adhesive backed paper, 40lb. The glue on the paper I use is very strong, bonds hard to a well sanded fin. No glues to worry about.

Oh, if you try this, buy MATTE paper, not glossy.

Click to expand...

Where would I find that? Source? Brand / Product Name? Thanks.

avery brand label paper is one,, it's very strong
you will pull off balsa if you try to peel it back off

Originally posted by Mad Rocketeer
Where would I find that? Source? Brand / Product Name? Thanks.

Click to expand...

I ran out and had to buy some for my Renegade build. I bought Spinaker Strip-Tac #09598. It's 60lb, not 40, sorry 'bout that. Strong, strong, strong.

Manufacturer doesn't really matter, you'll pay about $15 for 100 sheet pack, make sure it's offset, or matte, just not glossy, unless that really what you want. 100 sheets will last you forever, make good stock for simple white body-wraps, too.

I'm building a Fliskits ACME soon, and I downloaded Jim's body wraps to print them on this paper. First 100% body wrap finish, since even the fins have wraps from Jim.

Jim recommends Avery 5265, FYI.

Would I need to go to an office supply store to find that, or would Wal-Mart, etc., be likely to carry it?

Originally posted by Mad Rocketeer
Would I need to go to an office supply store to find that, or would Wal-Mart, etc., be likely to carry it?

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Your best bet is PAPER SUPPLY store, office supply stores would be my second stop, though they surely carry the full sheet Avery labels. If you have a paper supply store (Paper Plus here in Bakersfield), start there.

And call. Save yourself the aggravation.

So do I understand you guys right?

I've never had a problem with a fin cracking, yet, knock-on-wood. But after sanding the fins down, you add the paper on top, and then paint?

Does it really add that much strength?

Oooooh, yes. Adding the paper strengthens two ways.

1. It adds the ability of a non-breaking surface to the balsa so shock-breaks are resisted.
2. It fully spreads the impacts that do occur evenly out across the fin.

You will want to CA the trailing edges to give them extra firmness, too.

I encourage all you guys to try a TRF search for old posts about laminating fins. There is lots of knowledge and experience already written up, enough stuff to keep you reading for several days.

Originally posted by powderburner
I encourage all you guys to try a TRF search for old posts about laminating fins. There is lots of knowledge and experience already written up, enough stuff to keep you reading for several days.

Click to expand...

Yeah. I was involved myself in some threads on that some time back. Lots'a good stuff. I just lost track of the old threads and had a lingering doubt about water-based glues drying properly.

Originally posted by JBeau
I've been extremely pleased with the ease of use and strength of adhesive backed paper, 40lb. The glue on the paper I use is very strong, bonds hard to a well sanded fin. No glues to worry about.

Oh, if you try this, buy MATTE paper, not glossy.

Click to expand...

JBeau: Thank you for suggesting the adhesive-backed paper. I've tried the 3M spray (strong but messy), contact cement (same), and even shelf paper (easy but not very smooth). After reading your note, I went to Staples and picked up a pack of 25 sheets (20 lb stock).

It was easy, and it appears to be quite strong. I used it on my second Big Daddy. I consumed 2 1/2 sheets for the Big Daddy so the supply will last a while. I was worried about the "stick" of the paper. But it's solid particularly after using thin CA on the edges.

I had gotten into the habit of substituting basswood for the balsa provided in kits (tedious and wasteful), but the adhesive-backed paper is so easy and effective, I'll rethink that practice. I'm sure the papered fins aren't quite as strong as the basswood, but it's pretty good.

I've only primed the Big Daddy so far (painting is tough in the winter), but the fins are smooth and strong. The paper was a bit fuzzy where I had sanded the margins of the epoxy fillets. But the fuzziness disappeared after priming and light sanding. It will take the paint just fine. Pictures will be posted later.

Overall, it's the easiest method I've seen so far to reinforce the fins. I'll look for and trying the heavier paper in the future.

Ron

Excellent! And I concur completely with your comments. The adhesive is strong, paper paints well, and is superior in ease and strength and application.

Thanks for the feedback.

Has anyone ever tested the various ways of laminating fins for strength? It would be interesting to find out what papers (like printer paper, Japanese tissue) and adhesives (like 3m spray, CA, wood glue) are strongest and lightest.