And also many thanks to all the builders who are delivering
information via this builders group or websites.
It is a huge source of information for your collegeas.
Marc
PH-REB
-----Oorspronkelijk bericht-----
Van: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] Namens Wayne G.
O'Shea
Verzonden: zondag 12 februari 2012 2:26
Aan: rebel-builders@dcsol.com
Onderwerp: Re: [rebel-builders] Building a leak free fuel tank.. Rebel,
Elite, SR,
So today's exercise was placing a Rebel tank bottom skin (5.5 hours
total)..... 3 bays.
...would be easiest for the followers if they just viewed the pic on this
link to my facebook album on this tank rebuild.
https://www.facebook.com/media/set/?set ... 0002254597
941&type=3&l=2f4b4f80dd
Overview..
Preparation = exacto knife to carefully trim smooth any bumps where you
filled the stringer(s) and corners to give a good sealing surface. Being
careful to NOT peel any sealer from aluminum faces.
Use a #30 drill bit in your hand to carefully clean out any rivet holes that
have sealer in them. Do not push down, just carefully turn until you have a
pocket deep enough for the rivets. Critical in the stringer to rib filled
area. Be extra careful not to push.. or you may peel the semi-cured sealer
away from the stringer surfaces.
Get your "tools" ready.. and for me that equals a digital scale, 4" x 8"
alum mixing tray (scrap .025), rivet gun, back up hand riveter, 1" putty
knife, a 16" length of 5/16 wood dowel with the end rounded to a ball and
some tongue depressors. I use an unmolested depressor to extract the goooo
from the PRC can. Stir in circle... pull and at same time invert can. The
blob will start pouring out onto your mix plate on the digital scale. Then
another 1/2 of one to mix and extract the catalyst from it's container, at
1/10th the weight of the PRC, and plop it on top of the PRC. For applying I
use a full one that has the end cut square, as well as a couple more that
have been cut in half leaving a radius and one sharp side. The other I use
the belt sander and make it's ends round like a popsicle stick.
First thing mixed... 10ml of EP420 to 5 ml of EP430
Second thing mixed.. 120 grams of PRC to 12 grams catalyst. Trick is just
use the corner of the putty knife and stir in circles with the odd scrape
and flop of the entire mess.
Put cleco's in your tank skin...one at each hole where the tank mates each
END HOLE for each rib flange. Then one about every 6" on the stringer holes
and one at each rib to rear bulkhead overlap hole and one about mid span on
each rear bulkhead.
Use a wedge to lift the leading edge skin up off the main spar and if
necessary some wires to pull it back to give you clearance to place the tank
skin.
Coat all the mating seams of the tank skeleton with sealer, about 90 thou
deep. Front spar, rib flanges, stringer(s) and rear tank bulkheads.
Coat the tank skin ON THE OUTSIDE where it mates along the front spar (where
the leading edge skin overlaps).
Flip the skin over (it will sit on the cleco heads) and brush your EP420 on
the skin overlap area, that is outside the tank, being certain not to
contaminate any tank sealing surfaces.
Flip the skin.. get a good hold on the cleco's and carefully place the skin
"pegging" the clecos into the forward rib flange holes first. Do not
squeeze.. you're just aligning the holes at this point.
When you are sure the clecos are in the holes... start at the front outboard
corner and start cleoing the skin down to the structure, working you way
towards the root.
Remove the holding wires and wedge from the leading edge and cleco down the
leading edge skin, every 4 holes or so.
Throw a few clecos in the skin overlap outside the tank to insure it's
aligned.
Now start rolling the rivet ends and placing them one by one in all the
holes, paying attention to grip length (6402's majority... 6403's in main
spar and rear bulkhead to rib overlap spots). Turn the rivet slowly while
inserting if at all possible. Helps form a nice o-ring under the heads.
Once you have them all placed "1/2 pull" the rivets by either a quick
trigger touch if your gun will allow, or turn your pressure down to 30 psi
or so. Go around all the rivets to "tighten" them up. This will allow the
sealer to even out / oooz. Then go over them all again at 65 psi to set /
pull all the rivets. Remove the clecos and then roll rivets, place and pull
for all those spots that had clecos in them.
Now get inside quick and smear / smooth down any of the ooz before it sets
up. Only concern at this point is to smooth them out somewhat so it bonds
down to your crosshatch / scotchbrite work.
Dip your overlap rivets in EP420 and place and pull all those.
Now I've had great success in just stopping there and not bothering with
much else other than a few touch ups on the outer seams. But thinking I've
probably jinx'd myself typing all this verbal diahreah....
today I flipped the wing over and went to work in there sealing, smoothing
and coating rivets. I originally mixed another 80 + 8 PRC and a good part of
this went around the OUTSIDE of the rear tank bulkheads and the outboard
wing rib. Before I was done I had mixed another 50 + 5 PRC and had a bit
left over. So total use for today and building to the "bathtub" stage... 250
Grams of PRC.
I've now done both wing skeletons, sealed all 4 stringers in both tanks and
placed / sealed one bottom skin. I still have about 50 grams of PRC left in
the first can.
The tools..
http://www.irishfield.on.ca/gallery/prctools.jpg
Skin ready to place..
http://www.irishfield.on.ca/gallery/tan ... oplace.jpg
Rivets going in..
http://www.irishfield.on.ca/gallery/tan ... vetsin.jpg
All riveted
http://www.irishfield.on.ca/gallery/tankskindone.jpg
..and what that dowel with the ball end is for!
http://www.irishfield.on.ca/gallery/tankdoweluse.jpg
"Bathtub" ready to cure for a week or so before I cap the outlets and fill
it with 100LL !
http://www.irishfield.on.ca/gallery/tankbathtub.jpg
;o)
Wayne
----- Original Message -----
From: "Wayne G. O'Shea" <oifa@irishfield.on.ca>
To: <rebel-builders@dcsol.com>
Sent: Thursday, February 09, 2012 12:01 PM
Subject: Re: [rebel-builders] Building a leak free fuel tank.. Rebel, Elite,
SR,
Thanks Mike... just makes me wonder sometimes when folks ask for direction
on specifics, and when you decide to provide some they disappear. It's
like
they don't wanna know what's involved to do it right.
From yesterday... remember it takes longer than you think. 5 hours just to
seal / rivet the 2 spar fillers and 4 stringer fillers in place on both
tanks on their outboard tank ribs.
Total PRC used 240 grams... mixed in three batches of 80 PRC + 8 catalyst
For those that haven't spread this wonderful stuff they call PRC, Proseal,
etc, yet.... the only thing I can suggest to get the method down right is
to
help your wife icing a cake first!
And never lose sight of the fact you need to be absolutely sure you
haven't
trapped air pockets, as I suspect this is a large part of leak issues.
Very
easy to do.. caught myself at least 3 times yesterday with such things.
When filling the stringer curl... small amounts of sealer at a time...
scrape the popsicle stick (coated in sealer) on the edge of the curl and
make it work / pack it's way in to fill the curl. Repeat a few times to be
sure it's forced in there good and tight to seal it up. Now coat the rest
of
the stringer surface that's just inside the tank. (I'm talking about an
inch
out from the rib). Then coat the face of the outboard rib in the area of
the
filler plate and THEN put your metal filler clip in place over the
stringer
and slide it down the stringer thru the goo and into place and rivet. Then
you coat the plate, rivet heads and fill that stringer curl area again and
all surrounding areas (both sides of the rib). Then you make sure that the
gaps are filled between stringer and rib and it's flanges making a nice
sealing surface for the tank skin.
Of course be sure you prepped it right first as well... you needed to be
in
there on those stringers with the edge of a scotchbrite pad jammed TIGHT
into the curl to get it all scrubbed clean!
This shot shows exactly what those "clips" I make are for...
http://www.irishfield.on.ca/gallery/str ... ealed1.jpg
This one shows the outboard rib and stringers all sealed ready for the
bottom tank skin (once the sealer cures a bit so the rib doesn't move!)
http://www.irishfield.on.ca/gallery/str ... ealed2.jpg
;O)
Wayne
----- Original Message -----
From: <mikeh@dcsol.com>
To: <rebel-builders@dcsol.com>
Sent: Thursday, February 09, 2012 5:04 AM
Subject: Re: [rebel-builders] Building a leak free fuel tank.. Rebel,
Elite,
SR,
Wayne,
I know you are not talking to yourself, I'm sure there are many who
appreciate your input , not just on tanks. Please keep it up, you are a
valuable recourse for us builders.
Unfortunately for me, my wings are completed but haven't been used
yet, and after looking at your pics I think I'll leak test them again!
Keep it happening Cheers Mike 818R in OZ
On 2/7/2012 9:01 AM, oifa@irishfield.on.ca wrote to rebel-builders:
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