lwien, here's more useless information for you
, but maybe some other TubeZappers might find this worthwhile.
A tubing review as it pertains to the Myrtlezap:
I got the replacement soft blue tubing from Mcmaster in one day (they ship from my state).
I got both the 1/2" blue soft silicon tubing that fits over the outside of the stem and I got a 1/4" diameter soft silicon tubing that fits over the end of the Launch Box glass "elbow tube with a bubble" thing (I'm not a glass guy, I don't know what you call these things), so I could try both sizes of tubing.
Here's my verdict: the big 1/2" ID blue tube works very well and is way softer than the "firm" one I mistakenly bought, before. It can crease but not very easily. The occasional crease is not a problem, in other words.
Now as to which gives better vapor, the large tube or the small tube. I'm not really sure this was a fair test because I may not have gotten a super tight seal on the end of tube going into the bong down stem. I just shoved it in there until it seemed tight, then I also held it tight with my hand, and think I was getting a good seal.
I got very good vapor using this set up. However, the tube is rather unwieldy and awkward just due to the mass of it, being 5/8" outer diameter and somewhat heavy as a result.
But I got equally good vapor with the 1/4" tubing attached to the glass piece from Magic-Flight, and this is a much user friendlier set up in the sense that the 1/4" tubing is much less unwieldy and less likely to cause your Zap to fall over. It's kind of cool how it will swing around the long stem adaptor instead of pulling it over. The glass stem thing rotates 360 degrees with the tubing.
So I vote for the 1/4" ID tubing on the basis that it works equally well or close to it, and is more manageable. I'd be curious if someone else has tried that
and the 1/2" ID tubing, and has a differing opinion as far as which gives the best/bigger/easier hits. I wonder if having a GonG adaptor for the 1/2" tubing like I have with the 1/4" tubing would make it better?
Anyway, so here's my latest set up, with the 1/4" ID NSF-51 soft silicon rubber tubing from McMaster.com.