Dumb, Really Dumb

[NavyChief]

Ok, thought I had a really good idea when I was browsing the local hobby store. I would get some onion skin paper (what I used to call tracing paper) for its decreased weight over school paper and increased strength to use as a fin CA/paper trick. Boy, not a good idea. The paper only stuck to the fin about 45% of the area. Lots of air pockets even after I "squeegied" the extra CA out.

Now I have to either cut new fins or sand the heck out of the fin to get back to square one. Think I will stick with school "lined" paper from now on.

Fins are a part of a Estes Prowler kit that I am building. Modified - 24mm motor mount/stuffer tube (18" length) and Semroc baffle. I would like to put a altimeter in the top body tube, but have no experience in that (yet). :confused: :eek:

Tony

[CPMcGraw]

Ok, thought I had a really good idea when I was browsing the local hobby store. I would get some onion skin paper (what I used to call tracing paper) for its decreased weight over school paper and increased strength to use as a fin CA/paper trick. Boy, not a good idea. The paper only stuck to the fin about 45% of the area. Lots of air pockets even after I "squeegied" the extra CA out.

Now I have to either cut new fins or sand the heck out of the fin to get back to square one. Think I will stick with school "lined" paper from now on.

Fins are a part of a Estes Prowler kit that I am building. Modified - 24mm motor mount/stuffer tube (18" length) and Semroc baffle. I would like to put a altimeter in the top body tube, but have no experience in that (yet). :confused: :eek:

Tony

Go to Office Max/OfficeDepot/Staples (whichever is in your area - I have all three) and locate a pack of their full-page self-stick printer label sheets. The house brands are fine for this. All you need is to seal the outer edges [not the root edge, however -- leave this clean, or pre-coat the root with yellow glue] with this material, once it's pressed into place. The only sanding you need to deal with is the edges where the CA tends to form sharp ridges when it cures. Buff these down, and the fin is ready to go.

This is my preferred method now, and it seems to work without any delamination problems over time. I've got several that have been sealed, but not primed or painted, that are over a year old and have a number of flights on them. No delaminations.

[James Pierson]

CPMcGraw Quote:
This is my preferred method now, and it seems to work without any delamination problems over time. I've got several that have been sealed, but not primed or painted, that are over a year old and have a number of flights on them. No delaminations.

Yep, me too, and best of all no more sanding :cool: .

James Pierson
NAR# 77907

[Gus]

This is my preferred method now, and it seems to work without any delamination problems over time. I've got several that have been sealed, but not primed or painted, that are over a year old and have a number of flights on them. No delaminations.
Craig,

I used Avery full sheet label paper to do the fins on my BerthaVostok almost exactly 4 years ago. The paper was put down over bare fins, no primer or paint. Paper was printed on an HP inkjet printer and sealed to the fins with numerous coats of Rustoleum Painter's Choice Clear. Comparison pic of the fins then and now is below.

The rocket has had 20 or so flights, most recently this last summer at NARAM (where I got Vern to sign it as "co-designer", Sergei Korolev designed the other half). ;)

The fins have held up, for the most part, but have partially delaminated in spots, and frayed at the edges in others. More disturbing is the bubbling I'm beginning to see in spots as shown in the pic. The fins never got wet, haven't had any temperature cycling, and there were no bubbles originally, so I don't have a good explanation for it. For the first couple of years the fins looked fine.

Since the Bertha Vostok I have used this technique on a number of rockets where I want highly detailed graphics on the fins. I now spray the fins white (either primer or white paint) before applying the label paper. I do this primarily to keep the wood grain from showing through the lighter areas on the paper once it has been clear-coated, but I am now also hoping it will prevent the long term bubbling I'm beginning to see. Unfortunately, having to spray the fins first negates some of the ease-of-use of the technique.

Also, the necessity of leaving some bare wood at the fin root for fillets to stick to also presents added work. My technique is to apply the paper just short of the root edge and then use Apogee's epoxy clay for the fillets. For highly detailed fins where that is not an option I apply the paper all the way to the root edge and use epoxy to attach the fins, going fillet-less.

Because of the problems I'm seeing, I am no longer using the technique on regular fins. I've gone back to priming, sanding, and painting them. My suspicion is that the adhesive on the label paper degrades over time and somehow reacts with the dried clear coat to cause the problems.

I really loved this technique and still use it occasionally. But unfortunately I'm beginning to think it may end up getting filed with my other "I knew that was too good to be true" ideas. :(

[barone]

Craig,

I used Avery full sheet label paper to do the fins on my BerthaVostok almost exactly 4 years ago. The paper was put down over bare fins, no primer or paint. Paper was printed on an HP inkjet printer and sealed to the fins with numerous coats of Rustoleum Painter's Choice Clear. Comparison pic of the fins then and now is below.

The rocket has had 20 or so flights, most recently this last summer at NARAM (where I got Vern to sign it as "co-designer", Sergei Korolev designed the other half). ;)

The fins have held up, for the most part, but have partially delaminated in spots, and frayed at the edges in others. More disturbing is the bubbling I'm beginning to see in spots as shown in the pic. The fins never got wet, haven't had any temperature cycling, and there were no bubbles originally, so I don't have a good explanation for it. For the first couple of years the fins looked fine.

Since the Bertha Vostok I have used this technique on a number of rockets where I want highly detailed graphics on the fins. I now spray the fins white (either primer or white paint) before applying the label paper. I do this primarily to keep the wood grain from showing through the lighter areas on the paper once it has been clear-coated, but I am now also hoping it will prevent the long term bubbling I'm beginning to see. Unfortunately, having to spray the fins first negates some of the ease-of-use of the technique.

Also, the necessity of leaving some bare wood at the fin root for fillets to stick to also presents added work. My technique is to apply the paper just short of the root edge and then use Apogee's epoxy clay for the fillets. For highly detailed fins where that is not an option I apply the paper all the way to the root edge and use epoxy to attach the fins, going fillet-less.

Because of the problems I'm seeing, I am no longer using the technique on regular fins. I've gone back to priming, sanding, and painting them. My suspicion is that the adhesive on the label paper degrades over time and somehow reacts with the dried clear coat to cause the problems.

I really loved this technique and still use it occasionally. But unfortunately I'm beginning to think it may end up getting filed with my other "I knew that was too good to be true" ideas. :(
Still looks neat! I've been doing mine the hard way I quess. I use card stock, spray 3M adhesive to one side and then apply to fin. Rolling pin to make sure it has good contact. No long term results yet. But I figured if it was good enough to use on the paper wraps on my Saturn V, it's good enough to use on fins. Just a little messier than the full sheet adhesive backed stuff. Use tape in a reverse loop (you know, so it makes like double stick tape), and tape the pattern to a paper plate (not too tight though....just enough to keep it from blowing around when spraying the 3M adhesive). Then apply it to the fin. Sticks pretty quick so make sure you have it positioned correctly before apply pressure to it. Roll it out and then set it under something heavy while the glue sets up (doesn't take long). But man, what a mess if you get any on your fingers.... :o

[CPMcGraw]

...The paper was put down over bare fins, no primer or paint...The fins have held up, for the most part, but have partially delaminated in spots, and frayed at the edges in others. More disturbing is the bubbling I'm beginning to see in spots as shown in the pic...

Sorry to see that happening. On my rockets where I've used the technique, it's always been on bare wood fins, but I usually spray them with primer after assembly, so the paper is being sealed as well. I see what you're doing, which is a neat idea in principle, but I worried about leaving them unsealed. You clear-coated them, so I don't understand completely what happened. Since I spray primer over the paper, they get essentially a full "skin coat" over the paper which I think is filling the weave against moisture seeping in. And, of course, the primer gets either a color coat, or a clear coat, or both; so there's not much exposure to moisture remaining.

[Gus]

I thought as long as we are on the topic I should share another variation of this technique I use. Last year I built six Fliskits Acme Spitfires for a demonstration launch I do. The entire bodies of the Spitfires got the sticky paper graphics treatment, as well as the fins.

But rather than just doing the fronts and backs of the fins, I did full wraps which resulted in much nicer fin edges than would have been possible with the regular technique. Obviously the root edges are left bare. The difficult part is creating the outline for the fin wrap. But once you get the hang of where the "flaps" need to go, it's really not too difficult.

The montage below shows how it's done from start to finish, and five sets of finished fins.

The second photo shows all 6 of the Spitfires. Each Spitfire had 3 label paper body wraps, 4 fin wraps, and 2 cardstock shrouds. I also sticky paper graphic wrapped each launch lug and standoff. There were a total of 9 label paper wraps for each rocket. After construction the rockets were sprayed with multiple coats of Rustoleum Painters Choice Clear.

Both the fin wraps and body wraps have held up fine so far, but it's only been a little more than a year.

I did manage to hang one Spitfire in a tree during the launch. I recovered it a couple of months later after it had fallen to the ground. In spite of the rocket generally disintegrating from the rain and snow, the fin wraps held in place, and the sticky paper body wraps remained adhered to their underlying body tube sections. Pretty amazing.

[NavyChief]

Thanks guy for all the great ideas. I have used this CA/Paper trick before with no problems. I usually use the normal high school lined white paper and a coat of thin CA with absolutely no problems. This time around, I tried using tracing paper from an art store. High grade tracing/onion skin paper. Why?? Don't know, experimentation of what works and what don't before I start stepping into high power.

Tracing paper, I found out through my internet research is more like wax paper (for cooking in the kitchen) than it is the high school lined type. The CA really did not soak into the paper and through to the wood. I think that was my problem.

Since the kit shipped with balsa wood and I wanted something a little stronger with me modifying the rocket to 24mm AP motors, I went scrounging in the wood bin. I found some basswood 3/32 inch in the closet that was still unwarped. Recut the fins, shortened the TTW fin tab for a good fit. Now I am back to square one with treatment. I am going back to my tried and true method of thin coat of CA, let dry and very light sanding. Followed by a coat of sanding sealer for a smooth finish and a sanding. :)

Tony

[Mach1]

When I have lam'ed fins in the past, I usually used the header card that came with the Estes Kit, a cereral box, or a nutty bar box....well you get the idea.

I'd paste out wood glue over the surface, put the cardstock on,(glossy side out) and place it on a sheet of wax paper. Then I put a board on and add heavy weight on top of that. (if you don't the fin will warp)

After the 1st side was dry, I'd cut down the excess facing and repeat for the other side. Then fill and smooth all the edges (except the root edge) with F'n'F.

The result is a super strong fin that will not break or delam. The only downside is the extra thickness of he fin. Fin thickness issues can be compensated for by using thinner balsa.

[Mark II]

Don't kick yourself, Tony. I tried to do exactly the same thing with tracing paper not too long ago, and I had the same results. I think it was Edison who said that experiments are useful for teaching us what doesn't work.

Mark

[NavyChief]

Oh ssssooo true. I retired in 2005 from USN. I find your quote from Mr. Edison really true - 9 years as a CT and 14 years as a AT. Most of the equipment I worked on was old enough to be held together with bubblegum and bras cause they just did not make replacement parts.

r/
Anthony
US Navy Senior Chief Petty Officer (ret)
SI International
eLearning Application Developer

[barone]

........held together with bubblegum and bras cause they just did not make replacement parts.

r/
Anthony
US Navy Senior Chief Petty Officer (ret)
SI International
eLearning Application Developer
Oh visions of pink submarines here..... :D