The Zipperless Rocket

OK, I've got a real good one for you this time.

The name of the blog is The Thrifty Rocketeer, and I've got a great cost saving tip for you, provided that you use this method. Just bear with me...

For years, rocketeers have been looking for an alternative to the Estes rubber-strip shock cord.  And some people advocate totally skipping it in favor of a hard Kelvar string segment. Some even advocate a combination hybrid of half Kevlar and half rubber shock cord.

Well, I'm not going to debate that here. 

What reared its head was the tendency for Kevlar string (or similar hard, thin cord) to pull a zipper down a cardboard tube when it snaps taut.

The obvious solution is to either strengthen or pad the rim of the body tube, which is not practical, OR in some way, pad the string to spread the load and cushion the point where it bends over the body tube.

Some people slip a short piece of rubbery insulated wire coating (like shrink tubing?) over the string and knot it into place.

Some people have simply made a pad out of a pair of duct tape squares, adhered face to face, sealing the string inside.  Some just rip off a strip of duct tape twice as long as it is wide, and fold it over like a report folder, sealing the string as it runs inside.

But more inventive minds decided that they could produce a product that was designed specifically to adhere to the string at the appropriate point and pad the contact point.  I have actually seen this product for sale in a rocket parts distributor. 

 I believe they sold a small one inch square of wax paper with four tiny "footprints" die-cut out of construction foam. (For a better image, image if Ant-Man or the Atom were cutting a pair of flip-flops out of kid's construction foam.  The result would be a roughly peanut-shaped pad or cushion with adhesive on one side and peel off protective strip on the other.)  As I recall, these "pads" ran about two bucks for a pair of two... and I bought one unit when on clearance.

The foam footprints peeled off the protective wax paper square easily, and then, at the right point, pressed sticky face to face, adhered to each other.  They held tight and gripped well. I'm not sure why they didn't catch on, unless this was over-plumbing for a simple problem that duct tape could solve.

Anyway, it was this weekend that I was visiting a local public librarian to see about organizing a model rocket build class when I saw it.  I was awaiting her to print out her contact information for me on a piece of scratch paper, and I looked down at her desk.

Sitting there was a clear plastic container about the size of a can of cashews, with a clear cover that matched the walls of the container.  It was wrapped by a brightly colored label the described the contents as kids shapes and stickers.  Inside, clearly visible through the clear walls, were dozens of various shapes of foamy animals, objects, bowties and other shapes.  Each one was a different color foam pad, and had dozens of matching shape foam stickers jumbled inside.

Instantly, I recognized the value of the small bowtie shapes, and so I asked her for one or two. "Heck, you can take the whole jar," she generously offered.  I declined, but I did pluck out four of these stickers specifically for this blog.

Now, I don't know where to shop for these foamy stickers, but I'll bet they're at Dollar General, or Hobby Lobby, or Family Dollar or Wal-Mart or Under-a-Buck or maybe all of these places.  And I'll just bet that the cost of a container is only a buck.

THINK of how many pairs of pads you can fish out of a container like this!  For a single buck, you can put a Kevlar string pad on every one of your low power rockets and still have more to spare!

This has been the Thrifty Rocketeer saying, "Why not buy a jar for your whole rocketry club?"  (Remember, Easter is right around the corner, and your kids, nieces and nephews will all enjoy some brightly colored foam stickers, don't you think?)

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