When I had my tank and cobra (re/post) fluorinated by an industrial outfit, they
confirmed it to be LDPE, fwiw.
The finished treated tank had a severe frosted finish.... an indication that the
level of treatment was indeed higher than the factory's and I am hoping I will
have less swelling issues down the road.
Cheers,
Pete
On Jul 7, 2013, at 1:20 PM, Andrew Sarangan <asarangan@gmail.com> wrote:
>
> Thanks for all the ideas. The problem, as I understand now, is the
> attachment mechanism, and not necessarily the swelling. If the tank
> can be supported without bonding its surfaces, then it should be able
> to relieve the stresses as it expands and contracts. That's what I am
> gathering from these discussions.
>
> More puzzling is, it seems there is no agreement on what the tank is
> made of. Just in the last few emails, I've heard Polypropylene, HDPE,
> LDPE all mentioned, and Yerly's article says it is PTFE. I am somewhat
> familiar with different polymers, and these are all very different
> materials. I doubt it is PTFE because it is super expensive and
> nothing will stick to it. I know a chemical test to identify different
> polymers, but I would need a small chunk of the material. If I ever
> figure that out, I will make sure to post my results here.
>
>
>
>
>
> On Sun, Jul 7, 2013 at 3:43 AM, Duncan & Ami <ami-mcfadyean@talktalk.net>
> wrote:
>>
>> The tanks are low density polyethylene, I understand. And they shrink back
>> over time when left empty (but not in my experience by as much as the
>> initial expansion). Fluoridated tanks may be different.
>> The Kitfox company understood this problem in 1990.
>>
>> DMcF
>>
>> -----Original Message-----
>> From: owner-europa-list-server@matronics.com
>> [mailto:owner-europa-list-server@matronics.com] On Behalf Of andrew cullum
>> Sent: 06 July 2013 22:53
>> To: europa-list@matronics.com
>> Subject: Re: Europa-List: Fuel tank question
>>
>>
>> --> <asc23111964@hotmail.co.uk>
>>
>> Hi Andrew,
>> One question,have you filled your fuel tank with a mix of fuels you are
>> going to
>> use,and contained the tank with a sturdy wooden frame,and left it for at
>> least 6 weeks? The poly-propylene apparently expands by about 10 per cent
>> With the addition of fuel,this was in the old manual,but doesn't appear to
>> be in the new one. Could it be that tanks that have cracked haven't had this
>> pre-soaking? As for the cork at the bottom of the fuselage,sounds like a
>> good idea,I'm sure that Bud can help you out. Best Regards Andy Cullum.
>>
>>
>> Sent from my iPhone
>>
>> On 6 Jul 2013, at 20:47, "Andrew Sarangan" <asarangan@gmail.com> wrote:
>>
>>> --> <asarangan@gmail.com>
>>>
>>> After a one year pause, I am getting back into building. I am near the
>>> stage of bonding the fuel tank into the CM. I read a lot of
>>> discussions about tank swellings and cracking, so I am a bit
>>> concerned.
>>>
>>> Doing a google search, I came across a fuel tank mod document written
>>> by Bud Yerly where he suggests using a cork pad in the fuselage to
>>> support the tank. The details are a bit unclear to me, so I would like
>>> solicit opinions from anyone who can give me some insights.
>>>
>>> Thanks in advance!!
>
>
>
>
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