Shrouds

I have used thin CA on some of the Launch Pad kits with paper shrouds with good results so far.

Karl Perry QUARK, Cincinnati, OH

BB, Soaking cardstock in CA sounds like a good idea, at least for some applications. Some other things to try: posterboard, laminating over cardstock with kraft paper (and yellow glue), filling card stock shrouds with 2-part foam and using 1/64" plywood.

My cardstock shrouds usually look pretty slummy until I FNF them, then they come out pretty nice.

And I've done two 1/64" plywood boat tails that turned out nice. My 2-part foam fills have been less than stellar requiring lots of FNF to get them looking good. Same for laminating with kraft paper - lots of FNF needed - but the shroud came out rock hard.

Doug User of lots of FNF...

Laminate. I use two layer CA soaked tagboard for fins. But my strongest paper objects (conical nosecones, couplers, and bulkheads) are just two or three layers of PVA glued ink-jet printer paper over (index card) cardstock or tagboard. A glue SOAKED piece of paper doesn't wrinkle. Wet the paper thoroughly with glue, lay it on the cardstock form, smooth it down, and wipe off the excess glue with a damp paper towel. Experiment with a few layers and see if it has the strength you need.

It's basically just papier mache; the glue and the paper fibers form a synergistic bond.

Why not glue in some strips of urethane foam or balsa, sand to shape, then apply the paper shroud over that to give it a smooth surface?

For the Launch Pad rocket I worked on, a cone had to be glued to the nose. I used a 2 part foam to act as the glue, and boy did it do a perfect job. Not only did it fill the cone, it mushroomed into the hole I drilled in the tip of the nosecone. A very slight amount of filler and sanding and you cannot tell there was a modification. The foam really makes the cone addition solid.

Since this appears to be a wood fiber application, I don't see why Gorilla glue wouldn't perform the same function, for small cavities. If it's a large diameter transition, I'd probably build it by glassing over turned foam transition.

Joel. phx

we've had good results using Bristol Board instead of card stock. yesterday we made a shroud for a Delta II payload section (yes it is MER-B), BT-60 BT-80.

a couple layers of Bristol Board laminated with yellow glue, that would be plenty strong.

post some pix of the Vostok eh!!!

-- these are the good old days Cliff Sojourner snipped-for-privacy@employees.org

I am experimenting with scraps and so far this seems the best technique!

What's Bristol Board? So you're building a Delta 2 / MER-B? Cool! I would love to see some pics of that too. Will definitely post some Vostok photos.

"Cliff Sojourner" wrote:

I've used Bristol Board successfully.....it's available at art supply stores....ask for it.....I think I even saw at at AC Moore and/ or Michaels, where those 40% off & rare 50% off coupons come into play. If there are better for our purposes Bristol Board than others....weight, ply, etc., please someone educate us. I believe I first became aware of Bristol Board for shrouds from a Peter Alway publication. What IS tagboard. though? -- Richard "no profound comment" Hickok

Paper wrinkles primarily due to uneven liquid absorption by the fibers; placing a piece of plain bond paper over a thin film of wet glue is almost certain to result in wrinkles, especially if the glue is water based. Anyone who has tried the "paper reinforced balsa fin" technique has probably seen this. Wetting the paper with glue before application ensures enough moisture to go around and reduces wrinkles.

Tagboard is just a heavy paper with smooth surfaces, as opposed to the heavy papers with rough surfaces. I use index cards or manilla (file) folders. "Board" papers are usually used to make "things"; cards, folders, etc. "Bond" papers are usually written/printed upon. Also, I use paper to mean cellulose fiber (wood, in general) products.

Paper is actually a fascinating construction medium and you can make complex and fairly substantial assemblies with it.

I use thinned FNF painted over the shroud. Let it soak in and dry, then sand it down to smooth and soak it with thin CA. Pay attention to ventilation, it's going to smoke a bit when it goes off. Results in a paper shroud that feels more like a plastic part.

Works good for balsa nose cones and fins also, just make sure you have it shaped and smoothed before you hit it with the CA. You don't want to have to sand any more than you have to after the CA sets.

Bob Ellis

I've used .010 sheet styrene with pretty good success. It leaves a very smooth finish so basically all I have to do is bondo the seam. One thing that I also do with ALL of my shrouds is fill them with 2 part expanding foam.

-- Darrell Smith

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