Hi Jin,
I hope you haven't just managed to achieve the opposite to your desire
intention with this foam.
I believe this has been tried before on classic cars to seal various area
from water, and therefore rust, but everything I've heard is that it causes
the opposite.
It certainly did on my old Renault 5.
It seems that despite being closed cell it does still absorb some water,
especially once the surface skin has been broken, and in addition i think
that water that does get in then gets trapped between the steel and the foam
and is unable to evaporate.
I used it on my 2+2 in the pockets below the door hinges but it's not in
contact with the steel and was completely covered with fibreglass
afterwards.
If you want to seal places were fixings go into the steel then just use
Waxoil or non-setting windscreen sealer.
Jim
-----Original Message-----
From: jin
Sent: Saturday, July 07, 2012 8:23 PM
To: Quantum Owners Group
Subject: [Quantum Owners] foam filling the sills 2+2 waterproofing
So as many of you may know already I have a severe worry regarding the
sills my car filling up with water, this is not without reason
especially going by recent posts on here, however my concerns started
a long time ago – just after I bought the car and discovered it had
steel laminated in the sills as part of the structure and read stories
about owners drilling small holes in the sill fiberglass to fit screws
for later fixings only to find rusty water pouring out!, not why I
bought the car. but I suppose it’s my fault not checking first, having
said this id still rather have the quantum with steel in its sills and
know it’s extremely strong (anyone who has read the newspaper article
regarding the 2+2 hit by a lorry and several cars will know what I
mean) than say a GTM rossa that is prone to flexing even when jacking
up to change a wheel,!!!
So seeing as this is my best option I have been slowly improving the
situation by removing all pop rivets that enter into the sill / front
rear bulkhead sections and either removing them full stop or replacing
them with bonded in stainless steel studs instead
Additionally to this id made up a list of areas where water can enter
in, namely the seatbelt reel holes and the fuel filler neck if not
properly sealed, also the area where the filler spout fits through he
sill to the tank, on mine it was just sealed with a split / perished
badly fitting rubber disk - now totally sealed with proper bonded in
disks. add to this the cable for the sender was loosely placed through
an oversize hole in the opposite side sill there are many potential
entry points, possibly more I’ve not yet thought of, so I decided my
best option was to totally seal off the steel sills with foam so no
water or even condensation can get anywhere near them, especially
since once water gets in it can’t easily get out.
So after some research I decided the best option was to use this from
Dow engineering
http://www.dowautomotive.com/capabilities/product_family/betafoam.htm
It will essentially seal out the sills and stiffen the structure, it’s
the same stuff used in the Mazda RX8 front end for crash protection
and also the new BMW M5 uses it in the rear sub frame mounts to
prevent stress cracks in the structure, without the foam it cracks.
Some other articles I’ve read on this type of structural foam (as it
is called, not to be confused with the stuff from B&Q) are solely for
the purposes of chassis stiffness
The best reference I have read is here
http://www.sr20-forum.com/suspension/11917-foam-filling-chassis.html
The foam I’m using is the same density, if it stiffens the chassis it
will be a bonus however my sole reason is to seal out moisture, this
is high density closed cell foam
Trial runs
it has been in my mind that there could be an issue of over filling
the sills and damaging the fiberglass / cracking the gel coat, the
foam selected is quick rising – literally seconds to full expansion,
so by the time it travels down a 4 ft. long probe it will have done
most of its expanding so I’ll just be pouring in to fill the sills
under the pressure of the tanks and not excess pressure via expansion,
but for this to work ill need to see the foam as it expands, this will
be impossible inside the void between the steel sill and the outer
body sill (my main area of concern) without cutting a hole in one end,
so after much head scratching I decide on the rear edge as its flatter
compared to the front and easier to seal off afterwards.
To mimic the sill I made a mock up using cardboard, the theory being
if I can control the process enough to not damage the cardboard I’ll
be fine on the car, I made up a 50mm x 150mm box section to roughly
mimic the void
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
13062012365.jpg[/IMG]
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
13062012369.jpg[/IMG]
Nozzles assembled and gun purged
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
13062012367.jpg[/IMG]
PVC hose bonded to the end of the mixing nozzle
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
13062012366.jpg[/IMG]
First fill
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
13062012370.jpg[/IMG]
No distortion
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
13062012373.jpg[/IMG]
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
13062012372.jpg[/IMG]
Thin card box
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
13062012374.jpg[/IMG]
Again no distortion and total fill
The sum total of the trial runs
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
13062012371.jpg[/IMG]
Just in case you were wondering how strong structural foam actually
is, the long box section made from single ply cardboard can now
support my weight when span over 2 work tables, that’s quite a feat.
The big day
Firs job was to pull out all the absorbent pads and silica gel pack id
put in 2 years ago
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
03072012381.jpg[/IMG]
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
03072012382.jpg[/IMG]
Identify the not so obvious openings needed to be sealed
Inside the boot looking in towards the inner side pocket
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012383.jpg[/IMG]
View down inside the inner side rear pocket
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012384.jpg[/IMG]
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012386.jpg[/IMG]
Time to cut the sill rear edge, 44mm hole saw and gritted teeth
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012387.jpg[/IMG]
I chose this area as its thick enough to retain rigidity and I know of
other owners who have cut this area successfully to access the rear
trailing arm nuts without issue (incidentally mine are captive on a
welded plate bonded into the sill 2 years ago during rebuild #1 – see
rebuild thread)
With a strip light held close to the outside of the sill, just enough
light passes through the gel coat to illuminate the whole cavity (one
of the benefits of light colour gel coat)
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012390.jpg[/IMG]
Despite all my concerns, for some reason my steel members are in near
perfect condition, which is a miracle since the filler neck had spent
15 years not actually sealed to the outer bodywork and the front inner
door / wing pocket had not been sealed at all just above the sill
member - a common 2+2 fault
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012389.jpg[/IMG]
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012391.jpg[/IMG]
The rusty stain at the base is just superficial and on the rear tip
only
Tube inserted inside with the aid of a wooden dowel to overcome the
shape inside
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012393.jpg[/IMG]
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012394.jpg[/IMG]
Nozzle assembled
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012395.jpg[/IMG]
First pass
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012396.jpg[/IMG]
Not filled to the end just yet, I had some fiberglass panels made up
to the same thickness of the sills to bond on
To the inner face
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012404.jpg[/IMG]
Dropped down inside the sill with fiberglass resin smeared round the
inside of the hole and pulled home by the screw
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012406.jpg[/IMG]
Them foamed down behind from inside the rear side pockets, this then
was concentrated to the other openings I wanted to seal but trying to
not over fill the rear side pockets
Inside the rear bulkhead
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012398.jpg[/IMG]
Rear boot edges
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012411.jpg[/IMG]
Can’t say I’ve not been generous
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012399.jpg[/IMG]
Quick trim
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012400.jpg[/IMG]
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012401.jpg[/IMG]
Passenger side sill
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012402.jpg[/IMG]
First fill
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012403.jpg[/IMG]
Same process, all filled in on top, this filling the inside after
bonding on the fiberglass closing paned reinforces the join by pushing
the panel tight to the inside of the sill as the resin sets
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012409.jpg[/IMG]
This is by no means finished, I’ve got to sand down and shape all the
foam then cover the whole areas of exposed foam with fiberglass and
resin, I’m just taking a break from curling myself up in the car to do
the jobs, the fiberglass and resin isn’t entirely necessary since as I
mentioned before the foam is immensely strong and waterproof, but it
looks untidy and will be a better job finished off with mat and resin
The front
Although the main area of my concern was the rear, there is still a
void at the front, not as big but it’s a void none the less, I really
don’t think this part was entirely necessary but where there’s air
there is potentially moisture / condensation, also most 2+2 have self-
tappers and pop rivets in the lower edges of the bulkhead to secure
the bonnet locators and inner wheel arches, both a potential source of
water ingress especially if they work loose, I’ve replaced mine with
stainless studs during the last rebuild but with I’ve got the kit out
I may as well
15mm hole cut, small probe inserted to meet the top of the foam that
had travelled up from the sill pass, about quarter way down so it had
crept up well
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012415.jpg[/IMG]
Filled then plugged with my finger to force expansion into all the
nooks and crannies
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012417.jpg[/IMG]
Then tapped to 3/8 BSP
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
04072012418.jpg[/IMG]
Brass BSP plug sand blasted to remove shiny non-stick plating a
provide a rough key for resin to bond to, then the tapped void was
filled with a dash of resin and the plug inserted to just below
surface level
[IMG]http://i120.photobucket.com/albums/o192/jindal/2012%20quantum/
06072012422.jpg[/IMG]
Again I’ll be gel coating over this once set to restore the finish,
Job so far done,
The next step will be to shape and contour the foam to a uniform and
useable shape ready to glass in with mat and resin (already started
this, pictures to follow) and I’m considering filling the inside of
the steel beams with foam also to ensure the whole structure is 100%
sealed but I’m still deciding on the best place to inject the foam
into,
To be continued……
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IMPORTANT NOTE: All information presented herewith is provided on an "As Is"
basis, without warranty or the implication thereof. Neither the Quantum Owners Club nor
the individuals associated with the Quantum Owners Club or in the preparation of the
above information shall have any liability to any person or entity with respect to
liability, loss, or damage caused or alleged to be caused directly or indirectly by the
instructions contained within this or related message(s).
