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Old 05-18-2010, 11:20 PM
GlueyFingers GlueyFingers is offline
Intermediate Rocketeer
 
Join Date: May 2010
Posts: 31
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I've been having some success spiral winding tubes, and recently solved one problem that had been really frustrating.

Due to the spiral winds, some glue inevitably leaks through onto the mandrel, so it's necessary to either have a teflon coated mandrel (I wish) or cover it with something. Wax paper was the obvious choice. But contrary to 1001 plan instructions, white glue does stick to wax paper to some degree. Pulling the tube and wax paper off the mandrel was no problem, but getting the waxed paper out of the tube was. Well, I just solved that.

Step 1 - as soon as the glue has set up to hold the wraps down (and before any ironing), slide it off the mandrel, almost certainly bringing the waxed paper along

Step 2 - fish a piece of string through the wax paper tube inside the newly formed body tube

Step 3 - twist the far end of the wax paper around the string and tie the string to the outside of the twist.

Step 4 - now pull it out the other end with the string. Since it's being pulled from inside, the waxed paper is being separated in only a small circumferential area at a time, so the tension isn't enough to tear it.

As for materials, I started with poster board, which is workable, then did some with a roll of craft paper which is more tricky, as it swells when it gets glue on it. Cutting it into absolutely straight strips helps minimize the spiral effect - I use a rotary fabric cutter. Any edge imperfections could lead to overlaps and exaggerated spirals. Leaving a tiny gap between the spirals on the lower layer helps especially with paper that tends to swell.

But a much better material for larger tubes (and I can't take credit as I've seen it mentioned before) is paper sheetrock joint tape. This has a very clean edge so its easy to conceal the spirals, and it glues up like a dream with no evidence of unglued sections as was common on the poster board. Try to pick a roll with less of a ridge down the center, though since I'm ironing the tubes on the mandrel as they dry this hasn't been much of a problem.

Just whipped up several slightly over BT55 (1.4" OD) tubes on PVC conduit mandrels. My two wrap tubes are about 16 mills wall and seem like they will hold together but have to be handled with care. I put a third wrap on one that had dried for a half hour or so and it is now 25 mills and much stronger.

Now I just have to see if I can split it accurately enough to wrap smaller mandrels, as the tape is a hair over 2" wide.
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