Proper alternative pneumatic tubes

[COPERNICON]

I have been looking for proper 3rd party/alternative pneumatic tubes to complete my older lego technic sets. So far i havent found many good alternatives to 1st gen and 2nd gen tubing.

1st gen (1984-1987) seems to be using a PU/PVC based tubing, i wasnt able to find any good alternatives. It is unclear what material tubes from the 2nd gen (1989-?, see set 8868) sets are, it doesnt look like silicone, it is also a very durable material, so far i havent found any good alternative. For 2.1 gen pneumatics some sort of stiffer silicone material seems to be used, or so i think at least, MouldKing and brikshop.eu has decent alternative tubing....

So far my favourite alternative tubing is FKM/Viton, it bends really well and is extremely durable, unfortunately it is quite expensive €3.5/meter on aliexpress. Silicone tubing can be a hit or miss, silicone seems to be to soft in general to hold any good pressure, it is also hard to find a good seller on aliexpress. I am wondering if generic rubber/latex or NBR tubing would be decent.

[Stereo]

I've used PVC cause it was available in about the right size (2mm id 4mm od), it's quite a bit stiffer than any official sets I've had, so it holds pressure well, but also more prone to kinks than any pneumatic sets.  I do have the older hose from 6881 which is similarly easy to kink but measures 3mm+4mm size so it's softer.  Haven't had a reason to try it with pneumatics.

Edited Thursday at 11:00 PM by Stereo

[aeh5040]

In the past I've used the ones sold on eBay specifically advertised as a substitute for Lego tubing (don't remember the exact seller). Naturally the seller must be making a profit and does not reveal their source, but I have found both the price and the function to be satisfactory.