ameyam

Hi,

the LHS in my area is closing down and they offered me an entire spool of neoprene tubing (Dubro, black, medium). Is this any good for glow or gas?

Ameyam

w8ye

My Feedback: (16)

It is good for gas

Lnewqban

Yes, it is very good for gasoline, diesel, or glow fuel.

ameyam

I know Tygon hardens over time and most people change it once a year. Is there some characteristics in neoprene I should be aware of?

Ameyam

MTK

I've had poor performance out of LHS neoprene gas lines. If you do outfit your plane with neoprene lines let me suggest that you check the line around the fittings periodically for splitting.

When I first returned to gas operation about 4 years ago,that's whatI used initially but theyonly lasted about 2 months. Failure mode was crazing at the fittings where they go over the nipples, and eventually leaking there.

PolyUrethane C210 formulation (ester based) in 1/8' x 3/16" size, or Viton 1/8 x 1/4", are you better products for the application. Viton is expensive tho, so be prepare to spend some money. I use and sell the PolyU since it is by far the best value. I am still running the original gas tank I outfitted 3 years ago all with original lines. Still just as flexible as when new.

GBR2

My Feedback: (1)

The DuBro stuff is OK but be aware that it has a seam rather than a one piece wall. Not really a good feature for a gas line.

TimBle

indeed, extruded tubing is what we're looking for

ameyam

Ok, best I return it. I was told that its very soft and suitable only for in-tank applications. What do you guys use inside the tank anyway? I took my tank out of storage after nearly a year due to health reasons and the Dubro tygon inside is so hard, the clunk doesnt even touch the bottom of the tank when dry

Ameyam

earlwb

The neoprene tubing works for glow or gas or model diesel engines too. It was the first fuel line used for most all of the model engines.
Neoprene is pretty handy for some things. On older Fox engines with the butterfly throttle carbs, they use a cast in tapered fuel fitting and neoprene won't slip off of the fitting. The same thing for engines with a crankcase pressure fitting, as sometimes regular tubing tends to slip off when the engine is running.

The main disadvantages of neoprene tubing is that it is not transparent so you can't see the fuel inside, then it tends to get hard over time and or crack eventually. But this doesn't mean you can get a year or more of service out of a piece of neoprene tubing.

Its advantages are that it works for glow or gasoline or model diesel fueled engines. Also it tends to bond itself with the fittings after a while and doesn't want to slip off then.

karolh

Use only with straight gasoline as it is not ethanol compatible.

Karol

ameyam

Our gas already has 5% (or something like that ethanol) mix, so thats out of question. I still dont get what to use inside and outside the fuel tank

Ameyam

karolh

Ever since I started leaving fuel in my tanks the Tygon that I use for in-tank plumbing has stayed quite flexible.

Karol

TimBle

Nonsense. Neoprene is fully compatibvle withEthyl alcohol (ethanol) but less so withgasoline.

For E85 Neoprene makes a better fuel line than Viton.

Viton offers best compromise with E10 since it is less affected by gasoline than Neoprene but when the ethanol content becomes high Neoprene and Nitrile rubbers are better choices.

MTK

I use the polyurethane that I talked about above and in 10 other threads.

Viton works okay too but get the softest you can find (60 duro) and use a heavy klunk such as a genuine walbro. Hobby neoprene, you are taking a chance......

Having said that, neoprene was one of the original rubbers used for gasoline lines in cars. But much of that performance was based on the compounder's ability to mix the right ingredienst during compounding. The raw neoprene stock is fine in gas. The rubber compound one actually usesisa mixture of many different things andmay or may not work.

And hobby neoprene rubber is often not that good. That's been my experience anyway

ameyam

As Karolh suggested, does leaving some gas in the tank keep the tygon flexible?

Given neoprene is too soft for use etc, I really need something that can remain flexible in the tank

Ameyam

TimBle

tygon will remain flexible as long as its kept wet. Now draining the tank and going flying next weekend is not the issue. but draining the tank and leaving the Tygon drain for months will affect its flexibility.

ameyam

TimBle,

thanks, thats what I wanted to know

Ameyam

TimBle

make sure you buy the neoprene fuel line from an automotive spares shop. They will either offer you nitrile rubber or neoprene rubber.

ameyam

TimBle,

If I get a large quantity of tygon, say a 30ft spool and use just a couple of feet for now, will the remaining harder over time on its own?

Ameyam

TimBle

All plastics harden. 

karolh

Really now, I use to use Dubro black seamless neoprene tubing exclusively for all my in-tank fuel lines until we switched to ethanol blended fuel and all the lines would swell after a short time and get all gooeys. Now if that is not being incompatible what is.

Karol

TimBle

That Dubro seamless "neoprene" tubing is not good neoprene. I use it for a vent line on my tanks and thats about it. For my fuel line I used Viton (but am now out) or Nitrile.

MTK

Tried nitrile early on when I was looking for a good replacement for Tygon PVC, the yellow stuff from LHS. It literally fell apart after 6 months. I'd be kiaful with nitrile.

Tygon is a trade name for all kinds of plastic products (St Gobain's trade name). Tygothane is just a different product within the broad family. There are two types of Tygothane available, one that is ether based and good for water and medical apps (falls apart in gas); the other is ester based and is good for many organic solvents (but not all), including gasoline and diesel (but falls apart in water). I have the complete library of products at work.

I don't recall seeing anything in the Tygothane family that has fruorine in it. I'll take another look. In general, anything containing fluorine is gonna be expensive, like 5X-10x the cost on the non-fluorinated plastics/rubbers.

TimBle

Yes I think you're right. Their fluoronanted tubing in the tygon range is Chemfluor.

The thing with Nitrile and Neoprene is they do not perform well when there's an aromatic present. Any toluene, xyelen or benzene in the fuel and its going to degrade if the line is of low quality.
Hence many people moved to Tygon and other polyurethane type fuel lines and Viton is becoming sort after as well.

bgw45

My Feedback: (1)

TimBle, I am needing to re-plumb all my tanks and am thinking about using Viton for inside the tank. Were you able to go more than a "flying season" before having to re-plumb?

If I have to re-plumb each season with the more expensive Viton, then it negates the benifits. Your thoughts