Hmm…. Not sure if my previous advice is completely sound. Some materials, such as rubber or heat-shrink tubing actually contract when heated. Since I don’t know what type of plastic goes into straws, I don’t know how they would respond to heat.
If the straw is too thick, and the paddle wont slide on it, then you might try something thinner. One possiblity is clear-tape. Clear tape usually has a fairly smooth and slippery surface. You could stick a line of tape to the rod, and see if that works. Probably, clear tape is thinner than a McDonalds’ straw.
The only downside is that the tape could leave a glue residue if you needed to remove/replace it. To remove the residue, you could use a solvent such as acetone. btw, do not use solvent on the paddles at all; acetone can soften or dissolve plastic. However, it should be just fine to use solvent on the metal rods.
If you don’t want to use solvent, you can use new clear-tape and repeated stick new tape on and peel it off; the old glue on the rod will stick at least partially to the new tape, and will peel off with it. At least, a little bit will peel off each time, so you need to do it repeatedly. This is an old trick my mother taught me for removing residual glue left from stickers on jars.
There is such a thing as Removable Scotch Tape. I suppose you could try that if you’re concerned about the glue residue. It may not be as thick or smooth as clear-tape, so probably should experiment with it first.
http://www.amazon.com/Scotch-Removable-Tape-Inches-224/dp/B001GXD2S2
Anyways, just my random thoughts about it. If you try any of these, or other ideas, let us know how it goes.
Sincerely,
–Lagrangian
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“What grit sharpens the mind?”–Zen Sharpening Koan
I wonder if you could heat the straws to make them expand slightly, and then slide them over the rods with a little WD-40 or something.
I have not tried this. But if you do, do not melt the straws! You don’t want that, as the straw will then deform and change thickness in uncontrolled ways. You want warm, but not melted. Maybe warm/hot tap water on the straws?
Sorry, just a random suggestion. I thought of this because of two things:
(1) When a jar cap was hard to open, my mother would heat it under hot water from the tap. The lid would expand, and it would be easier to open. I don’t know if this is because the cap heated more than the glass and/or the coefficient of expansion for metal is much larger than glass. The latter is true, the former is probably true too, but I’m not sure.
(2) In metal-work, there are extremely tight and nearly-permanent friction-fit parts. These are done by heating one part (say a precision hole) to make it thermally expand just enough enough for another part to fit (say an axel). After the two parts are joined, they let the hot part cool down to normal temperature, and by thermal-contraction it super-tightly squeezes the other piece. This is only a friction fit, but it can be so exceptionally tight that it is effectively a solid-join. In some machines, such a join is even used to transmit mechanical power.
Sincerely,
–Lagrangian
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