I have different sizes of clear flexible pvc tubing that I want to join together for water and vacuum lines,
e.g. (i.d. / o.d.) 6/10 mm tubing pushed inside 9/13 mm tubing.
What solvent or glue would be suitable ?j_sum1 - 18-5-2016 at 21:41
You can't weld them together by heating them over a flame for a bit?careysub - 18-5-2016 at 22:28
If it is really PVC then get PVC solvent at the hardware store, coat the end of the smaller tube and slip it inside the larger.
PVC solvent is generally THF (a really good PVC solvent), usually a second solvent, thickened with dissolved PVC.
I've solvent welded PVC before, but I've never tried flexible tubing.wg48 - 19-5-2016 at 00:40
I do not recommend using a glue designed for rigid pipe on flexible hose.
Even a plain solvent may harden the hose by dissolving out the plastizer which will cause it to crack after repeated stress.
Silicon rubber would better match the flexibility of the hose. It should applied to both pipes so its not pushed out of the way.
Ideally push the smaller pipe on to a short section of rigid pipe first then push the larger pipe over the smaller pipe having softened it with heat
first. Use diluted washing up liquid as lubricant and heat to soften both pipes. Clamp the result with a hose clip while its still warm. No glue
required and mechanicaly as strong as the hoses.
You can also buy multi diameter plastic coupling designed to join different hose diameters.
For more serous vacuum you can use silicon grease as the lubricant it also makes disassemble easier.
I just noticed if the hose is used at water main pressures the ideal method suggested above is mandatory and check the max pressure is suitable.
[Edited on 19-5-2016 by wg48]
[Edited on 19-5-2016 by wg48]Sulaiman - 31-5-2016 at 01:15
I tried a small glas tube inside the smaller pvc tubing and eventually, with silicone grease and heat, slipped the larger tubing over that ... works
great ... thanks.
Turns out I was over-thinking it / too cautious,
(to me, working outdoors with no suitable mask/respirator, and nearby neighbours,
chlorine gas is somewhere between scary and terrifying
soft pvc tubing slipped into a larger tight-fitting piece of tubing 'sticks' together well.
Unless I do something stupid, the maximum pressure in my system should be
the water pressure in the drip funnel
... a few inches of water max ... about +1 kpa
This would not be safe for a permanent or hidden piping system
but more than adequate for occasional experiments with observation. (I hope )TinSandwich - 31-5-2016 at 10:12
On a similar but somewhat unrelated note: what is pvc glue generally made of (apart THF) and is it of any use to us chemists?Orenousername - 1-6-2016 at 00:09
On a similar but somewhat unrelated note: what is pvc glue generally made of (apart THF) and is it of any use to us chemists?
It is probably just easier to buy THF, there's a ton of other gunk in it with (acetone, MEK, etc) and not to mention the PVC. Unless you think it's
worth cleaning pvc out of your glassware and performing very tedious (and probably inefficient) fractional distillation then I would just buy
THF/acetone/MEK.
