Bob H
Joined: 01 Dec 2006
Posts: 43
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 Posted: Fri Jan 31, 2014 8:39 am Post subject: Pulsar-List Digest: 5 Msgs - 01/28/14 |
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All organic materials will eventually be effected by solvents. The degree of
dissolution is a function of the specific materials involved and the
solvent's chemical activity, concentration and time and temp. For polymers
like epoxies, the degree of cross-linking determines the tendency to
dissolve and if it is a thermoset, the cross-linking density is higher so
dissolution is slower, measured in years of exposure. The higher the initial
cure temp, the better solvent resistance. A 350F cured epoxy resin will be
considered uneffected by gasoline with ethanol for years of exposure but a
room temp curing epoxy adhesive will begin the degradation process quicker.
When you have a structure that requires room temp construction (Pulsar
kits), those cured materials have a lower chemical resistance to direct
solvent exposure. The easiest remedy is to put a sacrificial coating of
higher solvent resistance material over the weaker base to keep the solvent
off the more susceptible material, and that's what the Jeffco novolac does.
Given years of constant exposure, that too will gradually degrade and will
need recoating to provide a new, resistant surface.
So this problem is systemic when fuels with solvent are exposed to epoxies
and you just coat the surfaces periodically to keep the underlying structure
sound. It's like painting a wood home every ten years.
Or you construct the tank from a metallic material that is uneffected by
solvent. It's too late to redesign and construct metal tanks in flying
Pulsar planes, so the protective coating, inspected and maintained, will
keep the wing structure from degrading.
Bob H
[quote] From: Pulsar-List Digest Server <pulsar-list(at)matronics.com>
Reply-To: <pulsar-list(at)matronics.com>
Date: Tue, 28 Jan 2014 23:58:46 -0800
To: Pulsar-List Digest List <pulsar-list-digest(at)matronics.com>
Subject: Pulsar-List Digest: 5 Msgs - 01/28/14
*
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Pulsar-List Digest Archive
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Total Messages Posted Tue 01/28/14: 5
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Today's Message Index:
----------------------
1. 08:10 AM - Pulsar 1 to Pulsar XP conversion (Sonja Englert)
2. 09:32 AM - Re: Re: Fw: Jeffco Epoxy (Bernard Wilder)
3. 04:07 PM - Shock Strut Attach Bracket (PreCompTech)
4. 04:57 PM - Re: Shock Strut Attach Bracket (pilot623)
5. 05:03 PM - Re: Shock Strut Attach Bracket (PreCompTech)
________________________________ Message 1
_____________________________________
Time: 08:10:52 AM PST US
Subject: Pulsar 1 to Pulsar XP conversion
From: Sonja Englert <paqs345(at)gmail.com>
Hi Group,
A number of Pulsar 1 kit owners have expressed the wish to upgrade
their Pulsar to a 4-stroke engine. This is generally not possible due
to the higher weight of the engine and the low gross weight their
structure was designed for.
I have now examined the wood wing and fuselage structure in detail,
calculated the loads for a gross weight increase and came up with a
number of reinforcements which brings the kit up to the same strength
as the Pulsar XP. This allows the use of a Rotax 912 engine and
increases all other limitations to those of a Pulsar XP.
The reinforcements can only be incorporated before any assembly of the
kit has taken place. It is not possible to upgrade a Pulsar 1 after it
has been built.
I am making the documentation available to Pulsar builders, please see
my web site http://www.caro-engineering.com under 'Pulsar Builder's
Support' for details.
Sonja
________________________________ Message 2
_____________________________________
Time: 09:32:37 AM PST US
Subject: Re: Re: Fwd: Jeffco Epoxy
From: Bernard Wilder <bernard.wilder2(at)gmail.com>
Jeffco 9700 is now Rhino 9700.(( Rhino of pick-up truck liner fame
bought them out.)) Google the manufacturers spec sheet and you will
find that it is a high quality cement paint with no mention of any
aircraft applications. I used it on my XP and found that after 13
years ethanol had almost completely dissolved it all away. I could
find no better material so I recoated my fuel cells with it again. I
keep a couple pieces of panel coated with 9700 in a quart jar filled
with MoGas. Every time I fly I give the jar a good shake. When the
coating on the piece in the jar gets thin I will know that it is time
to recoat my fuel cells.
BTW Rhino also makes a line of epoxy cements.
Bernie Wilder
On Tue, Jan 28, 2014 at 1:05 AM, PreCompTech <pctllc1(at)hotmail.com> wrote:
>
> We've used Jeffco 9700 Tank Sealer for many years with great results on
> aircraft
running jet fuel to standard gas.
>
> Biggest tip I can give is to make sure ALL pinholes and edges are sealed.
>
> --------
> Kris Anderson, Owner
> Precision Composites Technologies, LLC
> 509-521-7564
> www.precomptech.com
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=417742#417742
>
>
________________________________ Message 3
_____________________________________
Time: 04:07:17 PM PST US
Subject: Shock Strut Attach Bracket
From: "PreCompTech" <pctllc1(at)hotmail.com>
Part number AD355-A
Does anyone have an extra one of these around?
If not, I'm assuming it's made from 4130 steel and I can have my welder make
it.
Easier if one is on a shelf somewhere.
--------
Kris Anderson, Owner
Precision Composites Technologies, LLC
509-521-7564
www.precomptech.com
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=417794#417794
Attachments:
http://forums.matronics.com//files/image_250.jpg
________________________________ Message 4
_____________________________________
Time: 04:57:43 PM PST US
From: "pilot623" <pilot623(at)gmail.com>
Subject: RE: Shock Strut Attach Bracket
What is this part?
--
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