teflon (ptfe/plumber's) tape + vivi nova for leaking.

[erictho]

hey everyone.
heard about using ptfe to seal the vivi nova threads to fix leaking issues. I applied tape to threads on the bottom piece and it seems to work effectively. I initially taped the top cap as well but it was not very easy to trim the excess tape. I also worried about the tape being so close to the heating element. it seems to me that trying to cut the tape in half would be really challenging.
after a couple hours of use, i thought the liquid level was a little low for the amount i had been vaping. i set the vivi nova on a paper towel and there is slight leaking where the top cap is.
has anyone wrapped the threads on the top cap before? I figure I can wrap the threads and fold the excess tape inside the top cap. I use an evic on vw, usually to the wattage where my evic calculates 4.0-4.50v depending on the resistance. is anyone more knowledgable to the behavior of ptfe and whether it could melt/burn?
out of 11 vivi novas only 3 of them have this problem, very frustrating.
thx in advance.

 

[mostlyclassics]

erictho, it is possible to trim teflon tape, but you need an X-acto knife and a plate of glass or tile to do it effectively. Unroll a few inches, lay it on the glass, then use a finger to anchor the roll end of the tape and draw the blade right down the middle of the tape to the loose end. I've used both the #10 size (with a curved blade like a scalpel) and the #11 (straight-edge). The #10 size seems to work better. If you use a #11, make sure it's a brand-new blade, otherwise you'll get bunching. As you've discovered, the stuff is too limp to cut with scissors.

Teflon is used in non-stick frying pans and pots. Its melting point, says wikipedia, is 600 kelvin, which pencils out to about 600-625 degrees Farenheit, a few hundred degrees hotter than it'll face in a Vision Vivi Nova or Vision Vivi Nova Mini. It will start to pyrolize at about 400 degrees Farenheit, also much hotter than our devices get. Chemically, it's pretty inert: my father lived for about 30 years after he had some stenotic arteries in his feet lined with the stuff, and peripheral artery disease wasn't what got him in the end.

 

[StereoDreamer]

If your Vivi's re leaking at the cap threads, you are doing something VERY wrong with them, or they are cheap knock-offs that aren't made very well. Have you accidentally cross-threaded them before? If so, get a new plastic tank tube--they are inexpensive...

I always rub a drop of VG on the threads of my Vivi tubes when I put one together after cleaning them. Lubing up the threads with some PG or VG seems to help them thread together more smoothly, it seals the tank tube to the little gasket in the top and bottom caps better, and it has, in my experience, made the Vivi 100% leak-proof. Give that a try if you haven't already.

The problem with using plumbers tape on a Vivi is that plumbers tape is meant to be used in metal-on-metal joints, not on metal internal thread surrounded by thin plastic tube. You run a VERY significant risk of getting the tape too thick, and cracking your Vivi tank, or at the very least, stripping its threads...

 

[erictho]

mostlyclassics - thanks! i guess i should have thought to plug that into a google search, but thank you for sharing the information. currently i don't have any box cutters aside from a really basic one i swiped from an old job. the razor needs replacing and i should get another x-acto knife. but at least it will not break down at pv temperatures.

stereodreamer - the tanks with issues are all new. they are from vision, and they had issues on first use. the problem seems to come from the o-ring being slightly compressed in an area. i know about the problems from overtightening, so i haven't been doing that. also the threads seem to cut through 2 wraps of teflon, without harming the threads on the tube. i was pretty tentative and was sure to mind that. while maybe not for everyone, i found it to be really effective, and i don't think a $3.50 plastic tank is a huge deal.

 

[StereoDreamer]

Have you tried these tank tubes with other endcaps? Do they leak with other endcaps? Do the leaky endcaps leak with other tank tubes?

Seems to me the logical way to find a solution is to first identify the problem, rather than apply a theoretical "fix" that may or my not fix it, and may actually break a tube. And I understand that a $3.50 tube isn't a big deal, but if you're going to buy a replacement, and the problem might not be with the tank tube, why not buy a replacement right off, before you break one using plumbers tape to increase the thread size on the caps?

Because having extra parts at hand is always good thing, but breaking stuff under the guise of trial and error isn't... ;-)

 

[erictho]

one of the bottom plates i have used with another tube, and the tube with another bottom piece. in those two cases the bottom plate was the issue. the o-ring that came with it is imperfect on either end, which is what i'm sure is causing the problem.
teflon is designed to seal threads, so i'm not sweating it. the tape isn't even 1mm thick. maybe it'll break the plastic over time, but i doubt it. at least i'm not leaking at least $3.50 worth of liquid trying to use it.