>Viton - isn't that the same stuff that is found on the tips of fuel metering
>needles in the SU float bowls? Seems to me I've heard them referred to as
>"viton-tipped needles..." If so, would seem to be a good choice, with the
>exception of the -30 degree business. Might not be too good in Montana!
>
>Bill
>
> > Tygon is a clear plastic (PVC) tubing that resists fruit acids,
>> lye, achohol, greases, and oils. Autoclavable. Can be used
>> for temps from -27F to +212F (-33C to 100C). (From the
>> Fisher Scientific catalog.)
>>
>> Clear PVC tubing is a general purpose, clear, flexable plastic
>> tubing for transmission of fluids, gases, and some solids. Superior
>> resistance to strong acids, gasoline, oils in general, alcohol, and
>> hydrocarbons. (Note: brittle temp = -40C or -40F). (small parts
>> catalog).
>>
> > This discription indicates that it is suitable.
> >
>> Viton tubing:
>> This is a non clear tubing! but, it is a high performance synthetic rubber.
>> It offers the widest range of fluid and chemical resistance of any
>> commercial rubber. Excellent resistance to oils, fuels,
>> lubricants and most acids. Applications include fuel and oil lines,
>> cable jacketing, solvents, chemical lines, etc. etc. Brittle temp
>>-30F, -34C
>> (small parts catalog).
>> NOTE: I have used this stuff and it is indeed inpervious to chemical
> > attack. However it is not clear.
>>
Bill,
While the specification on Viton is not to cool it below -30F, I have had
much better luck w/ it in the lab. Mind you I was not using it as tubing,
but instead as a sealing 0-Ring for cryogenic fluids. I have also
used it to seal hot, gaseous hydrocloric acid (which eats thru aluminum
and silicon rubber o-rings). Viton did a wonderful job for that application.
I have however used Tygon to transfer liquid Nitrogen (-193C) and it does
indeed get brittle, fracture and cause quite a mess. Natural rubber
or silicon rubber is much better for wide temperature fluctuations.
One problem though is that Viton is not clear. It is a black/brownish rubber.
Since the original poster wanted to see the fuel going to the carbs, Viton
is not the material of choice.
Which gets us back to Tygon or some other (tefon, polyurethane, polyethelene)
tubing.
-Dave
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