chaskuss(at)yahoo.com
Guest
|
 Posted: Wed May 07, 2008 1:40 pm Post subject: Alodining Prior to Fuel Tank Sealing was Fw: RE: Proseal rem |
 |
|
I am resending this with the subject line changed to aid in easier searching of the archieves.
Charlie Kuss
--- On Wed, 5/7/08, Charles Kuss <chaskuss(at)yahoo.com> wrote:
| Quote: | From: Charles Kuss <chaskuss(at)yahoo.com>
Subject: RE: Proseal remover?
To: rv-list(at)matronics.com
Date: Wednesday, May 7, 2008, 5:35 PM
Jan,
The difference between "clear" and
"gold" Alodine (or Iridite) is only cosmetic.
They add a dye to the "gold" to aid you in
knowing when the chromic conversion process has completed.
I just did a quick search regarding the application of
Pro-Seal or Chem Seal (as supplied by Vans)
Here is what I found.
http://www.aviationproductsinc.com/Publications/TDS_PDF/TDS_CS3204.pdf
http://corporateportal.ppg.com/NR/rdonlyres/22FFA52B-AC2C-4D75-AE20-08E03ACF8EB8/0/asaguide.pdf
Both simply stress that the surface be clean.
I only know of several sets of fuel tanks which were built
locally, which were Alodined prior to sealing. No one has
had any sealing problems so far.
Charlie Kuss
--- On Wed, 5/7/08, jan <jan(at)claver.demon.co.uk>
wrote:
> From: jan <jan(at)claver.demon.co.uk>
> Subject: RE: Proseal remover?
> To: rv-list(at)matronics.com
> Date: Wednesday, May 7, 2008, 1:22 PM
> Hi Richard, (nothing wrong with perfection .. 
...)
> & Charles
>
>
>
> Is the reason for using clear and gold Alodine purely
> esthetic or is there a
> technical (chemical) reason why they are use on
different
> parts of the
> aircraft (at Boeing) ? I have used the
"gold"
> Alodine quite a lot - prior to
> painting ... on several parts of the RV I am building.
> Especially the spar.
>
>
>
> >From a adhesion point - paint does stick very well
to a
> Alodined surface -
> Does the maker of ProSeal have any official policy on
using
> Alodine prior to
> application of its product?
>
>
>
> Do you know "how many / how widely" the
practice
> of alodining the inside of
> the tanks are ??
>
>
>
> Jan
>
>
>
>
>
>
>
>
>
> _____
>
> From: owner-rv-list-server(at)matronics.com
> [mailto:owner-rv-list-server(at)matronics.com] On Behalf
Of
> RICHARD MILLER
> Sent: 07 May 2008 00:22
> To: rv-list(at)matronics.com
> Subject: Re: Proseal remover?
>
>
>
> hi guys
>
>
>
> jan i was taught to be a litle anal retentive and
by
> the way had to
> follow boeing spec's so everything gets alodined.
clear
> for skins and gold
> for every thing else. besides i like the color. and
water
> from bad fuel is
> bad for alum tanks.
>
>
>
> larry if they don't leak now why play with it. but
when
> they start to leak
> change them out when you pull the tank. it should only
take
> about an hour
> per tank.
>
>
>
> about fuel filters, airflow performance has a filter
prior
> to the twin pump
> setup it will stop any thing big enough to damage the
> pumps, but, big but,
> do you want to risk your bird on one fuel filter.
install
> one filter per
> tank prior to the selector valve. and sleep better at
> night. remember the
> airflow system much more pressure then a carb. i have
never
> like the one
> filter idea in certified aircraft. maybe i should
apply for
> an stc for two.
> airflow fuel filters are an annual replacement item,
> don't cheat
>
> Larry Bowen <larry(at)bowenaero.com> wrote:
>
> FYI, I used domed nut plates on my RV-8 tanks....and
had to
> cut a couple of
> them off because they interfered with the fuel
pick-up.
> Sometimes
> second-guessing uncle Van doesn't pay off....
>
> --
> Larry Bowen
> Larry(at)BowenAero.com
> http://BowenAero.com <http://bowenaero.com/>
>
> On Tue, May 6, 2008 at 2:14 PM, jan
> <jan(at)claver.demon.co.uk
> <mailto:jan(at)claver.demon.co.uk> > wrote:
>
> Hi Richard,
>
>
>
> I will be doing my hand build tanks later on this
summer. I
> have read your
> article with great interest. First ... I have bought
the
> domed nut plates...
> they are used on commercial planes from what I
understand
> ... and should
> make a perfect seal with a "O" ring .. Then
cover
> the nut plate after
> fitting with pro-seal as a extra safeguard against
leaks.
>
>
>
> Do you recommend alodining the tank skin and the ribs
??
> That is a new one
> to me ... I thought cleaning with Aluprep ...rinse
with
> water ... and scuff
> the seams is fine ??
>
>
>
> Appreciate you comments on this
>
>
>
> Best regards
>
>
>
> Jan
>
>
>
>
> _____
>
>
> From: owner-rv-list-server(at)matronics.com
> <mailto:owner-rv-list-server(at)matronics.com>
> [mailto:owner-rv-list-server(at)matronics.com
> <mailto:owner-rv-list-server(at)matronics.com> ] On
> Behalf Of RICHARD MILLER
> Sent: 06 May 2008 14:54
> To: rv-list(at)matronics.com
> <mailto:rv-list(at)matronics.com>
> Subject: Re: Proseal remover?
>
>
>
> Since we seem to have so many complaints about fuel
leaks,
> lets cover fuel
> tank 101.
>
>
>
> static loads on a fuel tank are less then .5 psi. duct
tape
> can hold .5 psi.
> dynamic loads are variable due to high g loading and
can
> reach 4
>
> psi, with tank destruction emanate. the problem with
> checking tanks is the
> static pressure loading is applied to all surfaces and
they
> need to be
> stressed to handle that load. most are not ie, the
caps.
>
>
>
> next problem is the inherent movement of the structure
as
> it flexes. tearing
> the sealant bonds.
>
>
>
> so lets assume that you built it close to right and
now
> want to test it.
> water, fuel, any material with the exception of the
> original sealant will
> contaminate the joint during testing. so how do we
remove
> the contaminates?
> we don't contaminate in the first place. the
sealants
> we are using are
> sensitive to contaminates so air or better nitrogen is
the
> testing medium of
> choice.
>
>
>
> after inspecting aircraft with properly applied
pro-seal
> that had over
> twenty years in service, the stuff sticks. sloshing
does
> not work and will
> result in a crash, the unfortunate part of this is
that the
> pilot is always
> the first person at the crash site.. fire and medic
support
> might take a
> little longer arriving. do not slosh tanks
>
>
>
> types of leaks.
>
>
>
> seam leaks, very rare, normally caused by poor
> construction, or extreme g
> loading.
>
>
>
> fastener leaks, more common also caused by high g
loading
> and flexing of the
> structure, compounded but poor sealing practices. all
tank
> fasteners are to
> be installed wet. and then sealed on the inside.
>
>
>
> access plate/fitting leaks, most common. cause
improperly
> applied sealant,
> wrong nut plates , they should be all domed and
sealed. too
> long of screw
> that goes through the nut plate dome. bad gaskets,
failed
> orings. rotation
> of a fitting after sealant has dried. always use two
> wrenches when removing
> lines.
>
>
>
> the primary problem with tank repair is the lack of
> structural integrity of
> this tank. riveted tanks and the repair tricks where
> designed around the
> larger transport type aircraft. pro-seal sticks well
and
> can be a problem to
> break the seams apart without disturbing/destroying
the
> structure.
>
>
>
> the best way that i have found to stop small leaks at
> fasteners and seams is
> to apply a heavy vacuum to the outside of the tank at
the
> effected area to
> draw any remaining fuel out and and suck the sealant
in to
> the void.
> additional rivets added along seam lines while still
wet
> helps to.
>
>
>
> sealant application tricks.
>
>
>
> clean /clean /clean. pro-seal dose not like oil and
most
> primers but loves a
> good cleaned alodined surface.
>
>
>
> mechanical grip/ light scuff on a flaying surface
helps
> with adhesion
>
>
>
> tape applied along side the joints to assist with
clean up
>
>
>
> gloves, this stuff does not like to come off and mek
is bad
> for you
>
>
>
> proper fit of parts, don't expect pro-seal to fill
> gaps.
>
>
>
> don't use to much. or you will get a wavy
structure.
>
>
>
> use type a for seams it helps with waves and type b
for
> fillets and fastener
> sealing
>
>
>
> don't exceed the pot life
>
>
>
> mix it right and use the correct proportions a good
scale
> really helps.
>
>
>
> use the longest pot life you can, i have found that
1/2
> stuff to be almost
> useless for most jobs.
>
>
>
> the proper place for sealant is on the inside of the
tank
> not globed on the
> outside beside it looks ugly.
>
>
>
> tips of opening seams
>
>
>
> sharpend putty knives are great but be sure to round
the
> corners to help
> prevent gouges. take your time here. gentle is better.
>
>
>
> removal of sealant
>
>
>
> scotch bright disks work great. wear a mask. and
realodine
> after done.
>
>
>
> tank testing, quick easy and cheap
>
>
>
> connect air/nitrogen supply to vent
>
> connect clear hose to drain about ten feet worth
>
> loop hose to floor and fill with water until you have
a
> loop with three feet
> high on both sides
>
> add nitrogen until the water is four feet higher on
one
> side then the other.
> you now have 2 psi in the tank. care should be taken
here,
> fill slowly.
>
> spray the seams with soapy water and look for bubbles.
use
> hand soap or
> aircraft soap, some soaps are bad for alum.
>
>
>
> how to find that damn mystery leak i have tried
everything
> else.
>
> sometimes really small leaks are the worse to find,
but one
> way to track
> them down is to apply dye-pen developer to the outside
of
> the tank it will
> show up any tiny leaks. over a couple of days.
>
>
>
> and this ends fuel tank 101 hope it helps.
>
>
>
>
>
> rick miller
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> _____
>
>
> Be a better friend, newshound, and
>
>
>
> http://www.matronics.com/contribution
> <http://www.matronics.com/contribution>
>
>
>
t="_blank">http://www.matronics.com/Navigator?RV-List
> <http://www.matronics.com/Navigator?RV-List>
> a>http://forums.matronics.com
> <http://forums.matronics.com/>
>
>
>
>
>
>
>
> _____
>
>
>
> Be a better friend, newshound, and
>
>
> <http://www.matronics.com/Navigator?RV-List>
> <http://www.matronics.com/contribution>
Be a better friend, newshound, and
know-it-all with Yahoo! Mobile. Try it now.
http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ
|
Be a better friend, newshound, and
know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ
| | - The Matronics RV-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV-List |
|
|
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
