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polaris

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I am thinking about making some card stock (110 lb paper) shrouds. I want to strengthen and stiffen them.

I have read some general things about using CA, epoxy, and foaming glues. Can anybody give some specific advice - what you used (brand names would be nice), kind of construction (boat tails, nosecones, transitions ...) and so on?
 

DynaSoar

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Originally posted by Polaris
I am thinking about making some card stock (110 lb paper) shrouds. I want to strengthen and stiffen them.

I have read some general things about using CA, epoxy, and foaming glues. Can anybody give some specific advice - what you used (brand names would be nice), kind of construction (boat tails, nosecones, transitions ...) and so on?
How big a bird? Ie., do you need to?

The Quest lifting body kits use shrouds and don't use any stiffener.
 

rbeckey

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One of the best ways to strenghten a paper shroud is with another one. Make it slightly smaller and use Devcon 5 minute epoxy. It will not bleed through the cardstock. I used this method for my Acme Spitfire tail cone and it is as strong as the tubes above it.

Art Applewhite suggests fiberglass drywall mesh tape with Devcon epoxy spread on it. It is sticky, so you can cut it to shape, apply it like tape, and spread the epoxy across it with a stick.
 

Missileman

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I have used 3/4 oz. fiberglass on several projects with cardstock shrouds, boatails and transitions.
The fiberglass was wetted on with 30 min. finishing epoxy.
 

powderburner

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I have made a few out of paper. I don't use fiberglass (too much mess). What I have learned is:

--Don't be afraid to throw it away and start over. It's only paper.
--A single layer of paper, or cardstock, or cardboard, is not enough. It will have to be reinforced with something like CA soaked into the paper, or epoxy coating the interior.
--It can be helpful to use double or triple thicknesses of paper in your fairing. And it can be a royal P.I.T.A. If you cut different pieces of paper and expect to 'nest' them for reinforcement, then do NOT glue them in final form before nesting. Fit the first one. Get it right at both ends of the fairing. Soak with CA and check for fit again. THEN roll the second (internal) layer of paper and dry-fit it inside the first. After it is snug in place you can tack the tab with a drop of CA, let it cure, and remove the second layer temporarily while you coat the inside of the first layer with epoxy.
--When you are rolling the external paper layer prior to assembly (gluing the tab), either smoothly bend the paper (be careful not to get any creases, dents, or sharp folds) to get your desired shape, or gently work the paper shroud across the edge of a desk or something so as to get a uniform bend/roll worked into the paper. Hard lesson learned: it is **very** easy to get a crease or dent in the outer layer, and it is very hard to cover it up with putty, primer, additional layers, etc.
--Don't be afraid to throw it away and start over. It's only paper.
--One or two layers of paper soaked with CA will harden up into a pretty tough fairing, at least for low-power purposes. If you need more strength than that, consider using a little foam to fill underneath the fairing, or a healthy dose of epoxy (this last one is pretty heavy)
--Don't be afraid to throw it away and start over. It's only paper.

Note: I think I over-stated things when I said "A single layer of paper, or cardstock, or cardboard, is not enough." Actually, I have built stuff with plain card-stock-type body work that held up quite nicely. And you probably do NOT want to soak those in CA because it will soak all the way through and discolor your wraps.
But I think if you work with paper to make these fairings and shapes, you will be a lot happier if you soak them with CA, and maybe add an extra layer if you want them to be REALLY tough. It adds weight, and it is probably overkill, but it sure works nice!
 

Micromeister

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I'll have to add my 2cents to this one.
Powderburner makes a couple good points..
....don't be afraid to throw it away and start over it's only paper!:D

....multi layer nesting shroulds is a great way to add some strength and a load of weight to the model.. but IS NO at all necessary.

There are a number of models that are/were entirely made of cardstock in the 65lb to 115lb class that have NO additional reinforcment at all... NO CA soak, NO fiberglass, Not even an overcoat of glue.
Centuri experimented and released several all cardstock kits, Quest has put out a few and many of us have been using the technique for years in Nar competition as well as sport flying. Sometimes on a very long Scale model transitions, where fins or other things are also being attached addition strength may be needed but for a straight shoulder or tailcone transition they should be fine just like they are. Models like "the Point, Vulcan, X-24 Bug, DCX, and several others are made entirely of 65lb cardstock, some with a central bodytube some without any other structure.. they fly and last just fine. Look at Fliskits "Midnight Express" it's all paper construction works just fine.
Don't let the overbuilders scare you into thinking a Paper, cardstock or light ply shroud, transition or nose cone are to fragile to fly... they are not, and work wonderfully for many flights. Many competition flyers use tracing vellum "paper tigers" in parachute, streamer and eggloft events to level the playing field with the single wrap fibreglass lay-up's the BTC's use. I know I'm one of them, and they can WIN:D
What do you think powder? a D12 Pd model made of single wrap of 100% Rag tracing vellum with the seam held with plain old Magic transparent tape? it works, is reuseable and very very light:) or a better example a dual egglofter with a 13" body taper shroud made of poster paper, again magic tape attached to a 24mm 3" long piece of body tube/ motor mount. This same model has flown in at least 5 meets over the past 6 ro 7 years.
Here's a composite pic of several different all paper or cardstock models, including a cluster altitude model with tracing paper transition.
Hope this helps
 

dr wogz

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What about some balsa 'ribs' inside the transion frustum.

some balsa traingles, glued to the smaller dia tube, and butted against the cenering ring of the larger dia tube. So the cardboard has 'internal fins' for support. Maybe 5 or 7 equally spaced around teh inside..

Or a few various outside dia centering rings, so there is a ring at about every 1/4 or 1/3 interval inside teh transision / frustum..

just making a few guesses... for whatever they are worth!
 

Micromeister

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Originally posted by Dr Wogz
What about some balsa 'ribs' inside the transion frustum.

some balsa traingles, glued to the smaller dia tube, and butted against the cenering ring of the larger dia tube. So the cardboard has 'internal fins' for support. Maybe 5 or 7 equally spaced around teh inside..

Or a few various outside dia centering rings, so there is a ring at about every 1/4 or 1/3 interval inside teh transision / frustum..

just making a few guesses... for whatever they are worth!
Balsa or CARDSTOCK ribs work well with Cardstock but cause visible creases in vellum or paper models. You'll get the same look with additional centering rings.

One thing I forgot to mention in the previous post was 3/64th inch 3 ply aircraft ply can be used on very large models just like paper. My 3X upscale Laser-X has this method on its transition and Cardstock over foamcore Main fins. very light and very strong.
 

Stymye

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the Quest dc-y utilises internal paper gussets
I preferr that technique if possible, it helps the shroud retain it's shape, I've found that a coating of cya works well
on the other hand my Applewhite 29mm cone is 110# cardstock with no re-enforcement/glues/coating at all, just paper! and flys on G motors with ease!
 

DynaSoar

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Originally posted by stymye
the Quest dc-y utilises internal paper gussets
I preferr that technique if possible, it helps the shroud retain it's shape, I've found that a coating of cya works well
on the other hand my Applewhite 29mm cone is 110# cardstock with no re-enforcement/glues/coating at all, just paper! and flys on G motors with ease!
Haven't built the DC-Y yet, but it seems plenty strong with those struts.

The HL-20 (a bit smaller) uses only assymetrical centering rings for support and it flies fine. It also lands nose first quite often and flies again. However, it has warped from water.

Thinking that, even if a shroud is strong enough, it might be a good policy to protect against dew and moist ground. I wonder how Scotchguard works on paper?

I've used a lot of lacquer sanding sealer to strengthen and smooth tubes, but it leaves a cludy finish. Not something to put on printed shroud. Except maybe inside.
 

Micromeister

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On most of the Printed shroud model in my collection I use krylon workable Fixatif to protect agains dew, water and the occasional candy coated kids hands:D
Most of the competition models are used raw, This Naram we flew several paper models in the rain.. one still got me a 126sec. B streamer flight:D Saved the fins,nosecone and shock cord parts to go into another paper tube for the next meet.
 

astronboy

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Here is my 2¢:

Paper (cardstock) shrouds have been used successfully for over 40 years in model rocketry. If you are flying A-C engines, a paper or cardstock shroud that is strengthened with model airplane dope (Old Skool) or CA is more than tough enough. I have about a dozen models that have paper shrouds, a few are even old enough to have them soaked with dope.

If you are building a larger model rocket, an epoxied double shroud may be in order. My 24mm, BT-70 based Redstone Missile uses this type of shroud, it is relatively light, and strong. I believe that anything up to an F should be OK with an epoxied, double cardstock shroud.

This of course may not apply to high power, as I have no experience in this area.

Phred
 

jetra2

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Actually, if you'd want to, you could use centering rings, wooden stringers, and 2-part expanding foam to make a transition. This is done often on LLPR, MPR, and HPR rockets.

Heeeyyyy....this sounds like a good project for tonight...sounds like a plan! I'll let ya know how it turns out!

Jason
 

BobH48

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I made a V2 entirely from 110 lb cardstock in a single layer. The only "real" model rocket parts were the engine tube and retainer.

This is durring construction
 

BobH48

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This was taken on it's second flight.

I used B6-4's for both flights and the model is in perfect shape.
 

BobH48

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I only have experience with cardstock shrouds with LPR.

For 18mm powered rockets, I use 110 lb. cardstock.

For Micro-Maxx and 13mm rockets, I have used 65 lb. coverstock without any problems.

I don't know how they would stand up to High Power.
 

Stones

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The transition/tailcone in my Bullpup AGM12-C are made of 2 layers of#110lb. cardstock, glued together with 3M 77 adhesive and have a CR in each end to hold the shape. She's gone up on a F52 reload and recovered without a scratch.
 

BobH48

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Originally posted by astronboy

Paper (cardstock) shrouds have been used successfully for over 40 years in model rocketry. If you are flying A-C engines, a paper or cardstock shroud that is strengthened with model airplane dope (Old Skool) or CA is more than tough enough. I have about a dozen models that have paper shrouds, a few are even old enough to have them soaked with dope.
I used to use model airplane dope years ago.

I don't use CA for this because the fumes bother me.

I have used Minwax Polycrylic and it seems to me that it's just as good as the dope was.
 

shockwaveriderz

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where/what are some sources for this 65# and 110# cardstock....got any name brands ?
 

Stymye

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I bought a pack(150 shts) of 110# from walmart,
it's just called 'Georgia pacific- card stock', I don't recall the exact price but it was no more than a few dollars. Im sure the office stores have a variety as well.
 

sandman

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Staples has a whole wall of paper in different weights and finishes.

I like the HammerMill brand 110# stock.

For 64# glossy stock Staples has their own brand at thier copy center. Have them print stuff for you (like $1.70 for a 11"x17" sheet).

While you're at Staples be sure to pick up a variety of colors (including silver and gold!) of Sharpie pens.

Very very usefull!

Keep 'em in your range box for "touch-ups.
 

BobH48

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where/what are some sources for this 65# and 110# cardstock....got any name brands ?

The 110# paper is usually called cardstock and the 65# paper is usually called coverstock.

I have found it at Walmart, Staples, Office Max.

Brand names: Hammermill, Georgia Pacific, Wausau Exact Bristol.

I'm sure there are others.
 

BobH48

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sandman,

Looks like you hit the submit button before me... didn't see your post until after I sent mine.

I agree with the HammerMill 110# stock.... very nice.

Good tip about the Sharpie pens.

I picked up a pack of 65# paper in a variety of bright colors (red, orange, yellow, blue).

You can roll your own Micro-Maxx body tubes and make up fins and have them pre-colored.
 

astronboy

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Yup, I get my 100# cardstock from Walmart too. It is the cheapest place I have found. I go through one package a year, and I print a decent amount of cardstock finpatterns, etc.

Phred
 

polaris

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Wow, what a great response from everyone. This has been very helpful, thanks.

The minute someone answers one of my questions, two more just pop up. So here they are:

I can see where you don’t have to stiffen cardstock shrouds all of the time. But in case you wanted to, it looks like CA is the choice. The CA I use is kind of thick. It doesn’t really seem to soak in. Do I have to thin it with something or is there some thinner kind of CA I just don’t know about?

The other question is about patterns. I use a drawing package for things like decals. I was thinking I could use it to lay out shrouds and then print onto 110# cardstock. I know there are some programs like VCP for simple conic transitions between body tubes. But how do you layout more complicated shapes and print them?
 

sandman

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But how do you layout more complicated shapes and print them?
Ahhh...there's the rub. It depends on what exactly you want to "lay out". Almost every shroud will be different.

You should have paid more attention in Geometry and Trig class.

Looks like you may have to do some research to lay it out correctly. I learned a long time ago that math is my friend.

I use QuickCAD to lay stuff out...after I've done the math.
 

vjp

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Polaris -

I'm a little late to this thread, let me describe how I made the shrouds for my Vostok, though.

I cut out two identical cardstock shrouds for each section, and (after taping up one on the outside, and one on the inside) brushed on a *very* thin layer of epoxy and nested them tightly together, with the seams opposite each other. Obviously, the inner shroud needs a tiny bit trimmed off the wide end, or it protrudes from the inner shroud a bit.

Then to squeeze them together even more tightly, and help them hold a round form, I used a second set of taped-up shrouds, lined with waxpaper (one inside and one outside, naturally) and squeezed the epoxied-up shroud pair between these. Let the epoxy cure, remove from the forms, and voila! Nice, strong shrouds.

Anyway, this technique is a lot of work and you may not want to bother with it, but I thought I'd share it anyway. It makes really strong, albeit a little heavy, shrouds.
 

DumasBro2

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Polaris,
What kind of shroud do you want to layout that VCP can't do? Also, I've had good luck using 1/64" ply instead of card stock. Easy to work with as you can cut it with a scissors. On cardboard shrouds I've had good luck covering them with 2 oz. glass. I usually glass the ply as well.

-steve
 

polaris

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Maybe I don’t understand everything I can do with VCP. But I think it is limited to right conical transitions (ones where the point is in line with the center of the circular base). It looks like I can do some frustums at the top of the cone.

I was looking to be able to do oblique conical transitions (ones where the point is not in line with the center of the circular base). I was also looking for something where both the top and bottom could be “cut off” at an angle.

I was hoping to be able to make flared fairings (where the cross section is a curve rather than a straight line like it is in a cone).

I also wanted to do be able to do the same things with other than a circular base – like maybe an ellipse, triangle or square. It would be nice if I could round off the corners of the triangle or square, too.

Wow, when I think about it, it sounds like I want everything.
 

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