No, I wasn't speaking of polyester. You can buy epoxies of different
ratios. I'm told by expert (Gary Hunter) that all epoxies which use ratios like
80/20 have significantly better mechanical and chemical properties.
Better properties to
what?
1. All epoxies uses strict ratios, as I
explained!
2. The ratios are set by the
manufacturers.
3. There are different quality Epoxy Resins - I
agree, but the quality can't be quantified by the ratio of the resin to
hardener alone, to my knowledge!
4. The dearer resins are quite obviously, better
quality!
5. The Quality resins are those most often used in
Aviation and there is comprehensive information available on structural
strength etc.
6. If someone where to use a cheap Epoxy without
researching it's properties - I would be very concerned.
7.Are you suggesting that people may use a cheaper
(non structural) resin to line fuel tanks and my therefore see a break-down of
the material sooner?
George (down under)
This is measurable, and agrees with my and other peoples tests. Like
I say, I tested all of the fuel tank components in various batches
of alcohol fuel for years (you know how I don't like design assumptions).
None of the components were affected. The only exception was when I exposed
50/50 epoxy mix to fuel. It slowly got mushy.
I have seen fuel tanks destroyed, leaking like a sieve from exposure to
alcohol fuel. One reportedly had old version of proseal inside. It completely
peeled off tank inside. Clogged fuel port. Forced landing. If memory
serves me correct, it also had poly that degraded by erosion. It looked like
someone had etched the poly out of the tank.
Al,
You must be speaking about Polyester as Epoxy
must absolutely maintain a strict ration mix, as per manufacturers
instructions, to allow proper molecule to molecule bonding of the
hardener and the resin. Polyester on the other hand has flexibility in that,
more hardener promotes hardening sooner.
George (down under)
I tested the hell out of that. No effect. Years of exposure to
different batches of known alcohol. I understand that if you use a resin
of high proportions of hardener to resin, it's resistant. If you use
50/50, it isn't. I had 50/50 get soft from fuel exposure.
This info consistent with all the other guys that did the same
test.
-al wick
Artificial intelligence in cockpit, Cozy IV powered
by stock Subaru 2.5
N9032U 200+ hours on engine/airframe from Portland,
Oregon
Prop construct, Subaru install, Risk assessment, Glass panel
design
info:
http://www.maddyhome.com/canardpages/pages/alwick/index.html
It will make it less attractive for those
with fiberglass tanks. Alcohol/gas mixes are more aggressive than either
gas or alcohol alone.
Bill Schertz
KIS Cruiser # 4045
----- Original Message -----
Sent: Tuesday, January 17, 2006
8:17 PM
Subject: [FlyRotary] Auto
fuel
By the Farm Bureau Paper it is stated
that Wisconsin has passed a law that all 87 no lead will contain 10%
alcohol and that nine other states are considering it. It didn't
mention the other no lead grades. Here in Michigan it is under
consideration at this time, and there is a good chance it pass.
Other than cutting the power some what, is going to effect the
operation of the rotary in some other way.
JohnD
-al wick
Artificial intelligence in
cockpit, Cozy IV powered by stock Subaru 2.5
N9032U 200+ hours on
engine/airframe from Portland, Oregon
Prop construct, Subaru install, Risk
assessment, Glass panel design
info:
http://www.maddyhome.com/canardpages/pages/alwick/index.html