Today's Message Index:
----------------------
1. 09:17 AM - Inside Fuel Cell (Bernard Wilder)
2. 06:22 PM - Fw: Fuel Tanks (Bernard Wilder)
3. 08:16 PM - Re: Fw: Fuel Tanks (GREGSMI@aol.com)
Message 1
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| Subject: | Inside Fuel Cell |
Attached are pics of the inside of my fuel cell.
Kit No. 390
Lay-ups within seem not to be damaged. I assume epoxy was used throughout.
Jeffco is an epoxy. Let me ask the dumb question: Does epoxy need to
be coated with another epoxy ? ? ?
Jeffco is a two part epoxy. Valspar garage floor coating is a two
part expoy. Is there a structural or chemical difference ? ? ?
I am working with a bladder manufacturer to see if a bladder is
aviable solution. There are some issues.
Comments ? ? ? ? ?
Bernie Wilder
Message 2
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---------- Forwarded message ----------
From: Bernard Wilder <bernard.wilder2@gmail.com>
Subject: Re: Fuel Tanks
Ray,
Fuel cells were coated by Aero Designs around 1995. I was told they
used something called Kreem ? ? ? ?
The white you see is where the coating has completely come off. There
was no residue inside the cell so the coating appears to have disolved
not chipped off..
The laminating poxy is whatever Aero Designs used to make the fast
build wing. Do you know what that was ? ? ?
At least one other builder I know of has had the coating inside the
fuel cell partially disappear.
I also heard from a chap in Germany whose XP fuel cells had areas
where the micro in the joint had not been covered by cloth lay-up and
had turned mushy. It had also turned white. The bond between the
fuel cell and the spar top was in his words "non existing" out
approximately 300 mm from the tank close out. Disturbing to say the
least. His wing had been built by Aero Designs.
I am going to copy this to the net so they can see all comments.
Thanks for your input.
Bernie Wilder
On Mon, Sep 30, 2013 at 4:28 PM, Ray Thurman <raythur@gvtc.com> wrote:
> First of all I'm no expert...
>
> It looks like the tanks were originally coated with Jeffco 9700 (now called
> Rhino 9700) based on the grey coating near the filler neck. What's all that
> white stuff??? It looks like ethanol reacted with your laminating epoxy
> (Epolite 2410?), or fuel has deposited a white substance, I don't know and
> can't tell from the pictures. I'd pick at it to see what it is or seems
> like, is it brittle or gummy or what. I'd also find a way to verify the
> integrity of the wet layups, maybe I'd pick at it to see if any areas are
> loose or pull up easily. Somehow you have to verify they are secure and
> strong. Once you're satisfied the glass layups are intact then it's a matter
> of surface prep and recoating. I'd go with the Rhino 9700 since it is known
> to resist the attacks of ethanol. I'm still puzzled why the original tank
> coating has failed.
>
> Jeffco (Rhino) is a Novolac based epoxy made for resistance to a wide
> variety of chemicals. Other floor coating epoxies probably are not.
>
> I really want to know what that white stuff is and what happened to the
> original tank coating. Were these built at Aero-Designs?
>
>
> Ray
>
>
> On 9/30/2013 11:15 AM, Bernard Wilder wrote:
>>
>> Attached are pics of the inside of my fuel cell.
>>
>> Kit No. 390
>>
>> Lay-ups within seem not to be damaged. I assume epoxy was used
>> throughout.
>>
>> Jeffco is an epoxy. Let me ask the dumb question: Does epoxy need to
>> be coated with another epoxy ? ? ?
>>
>> Jeffco is a two part epoxy. Valspar garage floor coating is a two
>> part expoy. Is there a structural or chemical difference ? ? ?
>>
>> I am working with a bladder manufacturer to see if a bladder is
>> aviable solution. There are some issues.
>>
>> Comments ? ? ? ? ?
>>
>> Bernie Wilder
Message 3
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| Subject: | Re: Fwd: Fuel Tanks |
Bob and all. In testing ethanol affects on different epoxies, we found that
everything we tested, both laminating and structural adhesive, would
dissolve if it was a room temperature cured bond. We also found that oven cured
composite was not affected. The composite formed parts use a prepreg
fiberglass that was formed in the mold then rolled into an oven for 4 - 8 hours
of cure.
We tested PRC sealed surfaces and found that PRC did resist ethanol. We did
not test Kreem.
These test were conducted with samples being exposed over a years time.
The conclusions are not too good. The tanks are attached to the wing during
the build process, using room temperature cured structural adhesive. If
the sealing agent fails, the epoxy joints are exposed to ethanol.
It would seem the best approach is to first inspect the sealant in the tank
and the bonding surface. Seal the tank with PRC or other products that
will resist ethanol. Then, do not use ethanol laced fuel.
Another option, after inspection and sealing is to use a fuel bladder
insert.
Remember when you built your aircraft, you attached the fuel tanks to the
spar with structural adhesive. If you bought a fast build wing, that just
means someone else did the same thing. Back then, ethanol was not being put
in auto fuel.
I hope others will chime in here. Maybe there are other options. I am just
relating to you the test I did with samples placed in a sealed jar of
ethanol auto fuel.
Greg
In a message dated 9/30/2013 8:23:08 P.M. Central Daylight Time,
bernard.wilder2@gmail.com writes:
--> Pulsar-List message posted by: Bernard Wilder
<bernard.wilder2@gmail.com>
---------- Forwarded message ----------
From: Bernard Wilder <bernard.wilder2@gmail.com>
Subject: Re: Fuel Tanks
Ray,
Fuel cells were coated by Aero Designs around 1995. I was told they
used something called Kreem ? ? ? ?
The white you see is where the coating has completely come off. There
was no residue inside the cell so the coating appears to have disolved
not chipped off..
The laminating poxy is whatever Aero Designs used to make the fast
build wing. Do you know what that was ? ? ?
At least one other builder I know of has had the coating inside the
fuel cell partially disappear.
I also heard from a chap in Germany whose XP fuel cells had areas
where the micro in the joint had not been covered by cloth lay-up and
had turned mushy. It had also turned white. The bond between the
fuel cell and the spar top was in his words "non existing" out
approximately 300 mm from the tank close out. Disturbing to say the
least. His wing had been built by Aero Designs.
I am going to copy this to the net so they can see all comments.
Thanks for your input.
Bernie Wilder
On Mon, Sep 30, 2013 at 4:28 PM, Ray Thurman <raythur@gvtc.com> wrote:
> First of all I'm no expert...
>
> It looks like the tanks were originally coated with Jeffco 9700 (now
called
> Rhino 9700) based on the grey coating near the filler neck. What's all
that
> white stuff??? It looks like ethanol reacted with your laminating epoxy
> (Epolite 2410?), or fuel has deposited a white substance, I don't know
and
> can't tell from the pictures. I'd pick at it to see what it is or seems
> like, is it brittle or gummy or what. I'd also find a way to verify the
> integrity of the wet layups, maybe I'd pick at it to see if any areas
are
> loose or pull up easily. Somehow you have to verify they are secure and
> strong. Once you're satisfied the glass layups are intact then it's a
matter
> of surface prep and recoating. I'd go with the Rhino 9700 since it is
known
> to resist the attacks of ethanol. I'm still puzzled why the original
tank
> coating has failed.
>
> Jeffco (Rhino) is a Novolac based epoxy made for resistance to a wide
> variety of chemicals. Other floor coating epoxies probably are not.
>
> I really want to know what that white stuff is and what happened to the
> original tank coating. Were these built at Aero-Designs?
>
>
> Ray
>
>
> On 9/30/2013 11:15 AM, Bernard Wilder wrote:
>>
>> Attached are pics of the inside of my fuel cell.
>>
>> Kit No. 390
>>
>> Lay-ups within seem not to be damaged. I assume epoxy was used
>> throughout.
>>
>> Jeffco is an epoxy. Let me ask the dumb question: Does epoxy need to
>> be coated with another epoxy ? ? ?
>>
>> Jeffco is a two part epoxy. Valspar garage floor coating is a two
>> part expoy. Is there a structural or chemical difference ? ? ?
>>
>> I am working with a bladder manufacturer to see if a bladder is
>> aviable solution. There are some issues.
>>
>> Comments ? ? ? ? ?
>>
>> Bernie Wilder
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