Fuel/Water, Bearing/Rust--More Action ** GREAT THREAD... **.

[Del Rykert]

I have found same issues as Bob mentions. Plane sits for long time and find
clunk & tubing degraded. Even brass tubing dis-integrated through stopper. I
never consider what the cause of the serious degradation was but after
reading this thread is making me have major 2nd thoughts about any brass in
use in our fuel systems. Do the Valves in our pumps now become suspect? Is
it only certain brands or certain ratios that aggravate the degradation?
Glad there are many smarter enthusiast than I to help guide us more mere
mortals. Would bronze serve better? Is it a true electrolysis or just d/t
brass being a soft metal? I'm am no metallurgist.

    del
----- Original Message ----- 
From: "Bob Pastorello" <rcaerobob at cox.net>
To: <discussion at nsrca.org>
Sent: Saturday, December 06, 2003 12:48 PM
Subject: Re: Fuel/Water, Bearing/Rust--More Action


| On a whim, I just removed the MK tank from my Viper.  Alas, it hasn't seen
| any fuel in awhile, tank was empty except for just what can't be drained
| through the klunk system.
|     So I took it apart, and the first discovery was a tarnished (but not
yet
| corroded) brass klunk.
|     The Second discovery was the unmistakable odor of acetic acid ON the
| klunk.  Sniff test of the tank confirmed the same smell.  A VERY small
| amount of fuel remains- I'm talking a 1/4 oz or less...and that odor was
| unmistakable.  Just like the smell from curing RTV, except not as
| pungent/strong.
|
| Theory - if all this chemistry is valid (and I don't have a clue) - the
| large amount of air in the empty tank, with whatever moisture is present
in
| it, does react with the exposed klunk material and the remaining fuel
| (methanol/nitro/oil) that was in the back of the tank.
|     At least it sure did smell like acetic acid and NOT "nitro"....as far
as
| I know Ritches' Brew doesn't include acetic acid in it's additives.
|
| Interesting stuff.  So I installed a new, undamaged, shiny plated
| klunk....we'll see...
|
| Bob Pastorello, Oklahoma
| NSRCA 199, AMA 46373
| rcaerobob at cox.net
| www.rcaerobats.net
|
|
|   ----- Original Message ----- 
|   From: Rcmaster199 at aol.com
|   To: discussion at nsrca.org
|   Sent: Saturday, December 06, 2003 1:19 PM
|   Subject: Fuel/Water, Bearing/Rust--More Action
|
|
|   Joe Wagner, similar to Clarence Lee of RCM, has given sage advice over
the
| years.For what its worth, I unwittingly used aluminum tubing in my Webra
| set-up from the start since that's all I had at the time. It's been almost
| 400 flights so far and the bearings still feel like new. It may be
| coincidence since the webra has larger bearings than the OS and Joe could
be
| mistaken, but it's easy to test the proposed concept.
|
|   I intend to use the information he passed on more completely, and see
for
| myself. I urge others to do the same covering all engine flavors. I will
use
| teflon or aluminum tubing everywhere possible , and use a teflon block as
| clunk. Can't replace the brass spray bar and nipples without machining
| capability, but the other changes should reduce brass contact at least
| fourfold.
|
|   Mine will be Webra and Mintors, and since both are AAC constructed, it
| automatically eliminates a possible source of catalysis
|
|   we'll see
|
|   Matt K
|
|   Bob Pastorello, Oklahoma
|   NSRCA 199, AMA 46373
|   rcaerobob at cox.net
|   www.rcaerobats.net
|
|
|   ----- Original Message ----- 
|   From: Rcmaster199 at aol.com


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