installing mylar
mmartin via AviationKB.com
LS3-A needs the seals replaced and am considering doing the job myself. Is
this something a reasonabley compitent person can do on his own, or should
this be left to a pro? Your input would be appreciated.
Regards
mmartin
--
Message posted via AviationKB.com
http://www.aviationkb.com/Uwe/Forums.aspx/soaring/200707/1
John Sinclair
if they follow the rules:
1. Remove all gunk with acetone and elbow grease.
2. Sand the new mylar (just the 10mm that will be sttached)
and the corresponding area on the wing with 220 dry.
3. Clean wing with acetone and apply the double-back-sticky,
making sure to follow the edge and keep it straight!
4. Clean the mylar with acetone and follow the edge
of the sticky very closely (don't make any abrupt corrections
or you will form a kink) Keep tention on the mylar
as you remove about 24' on protectice covering from
the sticky, as you work along. I work from left to
right, always!
5. Force Mylar down by running over it with a small
roller, I use a small roller bearing on a stick.
6. Clean with acetone and apply the transition tape
(I use 20mm)
NOTE, be sure to use mlar that is wide enough to cover
all hinge recesses, but don't go any wider than necessary
or stick forces will increase. Hinge recesses can be
covered separately with small pieces of plastic (mylar)
held down with sticky, then covered with wide tape.
Ideally, movement of the control should not lift the
mylar.
Have fun,
JJ
ContestID67
external seal tape, not internal seals.
The previous post mentioned sanding with 220. I didn't and wouldn't.
In my book
gelcoat and sandpaper should stay far, far, apart. The seals have
stuck for
3 years now with zero problems.
Having a friend help get things on straight is useful.
- John
bumper
"ContestID67" <jo...@derosaweb.com> wrote in message
news:1185850507.4...@r34g2000hsd.googlegroups.com...
John,
Your choice not to sand. However, if you check with some of the adhesive
mfgs(3M has good info on their site), you'll find that sanding is
recommended for optimal results with acrylic adhesive as are used to stick
down Mylar. Light sanding of the surfaces to be bonded is the way to go as
it provides the adhesive with more bonding surface and mechanical "bite".
As JJ noted, it's also important to have the surfaces squeaky clean, use
pressure (roller), and only apply tape to warm surfaces for best results.
Also position controls to keep pressure off the Mylars for a few hours as
acrylic gains strength over the first 24 or so.
bumper
Ray Lovinggood
problems with mylar not sticking to the double sided
tape. The tape sticks quite well to the gel coat,
but the mylar doesn't want to stay stuck to the double
sided tape.
I've been accused of having an engine on my glider
as I pass over the airfield. But it's just that damned
loose mylar buzzing.
Of course, the hardest part of dealing with mylar is
getting the old stuff completely removed. The next
hardest is figuring out how to insure the mylar stays
stuck to the double sided tape.
Any ideas?
Thanks,
Ray Lovinggood
Carrboro, North Carolina
LS1-d(t) :-)
At 06:12 31 July 2007, Bumper wrote:
>
>'ContestID67' wrote in message
>news:1185850507.4...@r34g2000hsd.googlegroups.com...
John Sinclair
won't hold the bond. I have seen a whole lot of mylar
that didn't stick over the years, but to my knowledge,
none has come off that I installed using light sanding
with 220 dry. I'm only talking about the 10mm strip
under the mylar. There's nothing new here, we must
sand before painting, we must sand before applying
resin. it gives the surface a 'tooth'. Every now and
then I see a fiberglass patch that someone has scabbed
on without sanding the surface, I just get a fingernail
under one side and off it comes easier than removing
wing tape.
JJ
>Of course, the hardest part of dealing with mylar is
>getting the old stuff completely removed. The next
>hardest is figuring out how to insure the mylar stays
>stuck to the double sided tape.
>
>Any ideas?
>
>Thanks,
>Ray Lovinggood
>Carrboro, North Carolina
>LS1-d(t) :-)
>
>At 06:12 31 July 2007, Bumper wrote:
>>
>>'ContestID67' wrote in message
>>news:1185850507.4...@r34g2000hsd.googlegroups.com...
mmartin via AviationKB.com
Thanks for the advice. I will be taking on this project this week. Also,
Awhile back there was a thread regarding the LS3 and landing gear. You had
mentioned about testing the gear gas spring by pushing on the overcenter lock.
I could have retracted the gear and there was no snap back to the down
position. Your advice saved me from the gear eventualy retracting on roll
out.
Thanks
Mike
>[quoted text clipped - 7 lines]
>>
>>mmartin
--
Message posted via AviationKB.com
gfoster07k
>
> - Show quoted text -
I have done this a couple of times and the seals were just fine for
about 5 years at a time. A couple of comments. The requirement to
get the old stuff off is critical. It means EVERY bit of the old
stuff so that the wing is pure white. The other comment relates to
the type of double sided tape. I used Tesa Polyester Tape used to
attach trim like chrome molding on cars. I got it at a body shop
supply store. My seals had been originally recessed into the gel coat
on top of the wings so the leading edge of the seal is flush and I
used a tape width that was as wide as the recess, (about 5/8 inch if I
remember right) to get maximum adhesion surface. The seals were
slightly cambered so the use of a small (linoleum in my case) roller
is also important to closely follow the removal of the tape second
side protective film. Otherwise the seal sticks at the inner and
outer edges due to the camber. Yes, I did 220 grit both the wing and
seal.
For what it is worth.
Greg .
John Sinclair
About the only thing I could add is to replace the
transition tape every couple of years. It doesn't hold
up too well and can be a bear to get off if allowed
to deteriorate too much. I buff out my bird every
other year and then replace the transition tape before
waxing everything.
Cheers,
JJ
While I'm pontificating, my bird has never gone together
well, the right wing always hangs up going on or off.
I marked both lift fittings with magic marker and forced
it together, then removed the wing to see just where
it was hanging up......forward side of forward lift
fitting and aft side of aft lift fitting! Looks like
my fuselage is a tad to small or my right wing is a
tad too big. What to do? I tried scrubbing the indicated
areas with emery cloth by scrubbing them like shinning
a shoe. Did this for a good hour and things got better,
but she still didn't go together easily. Next I wound
a 12' X 2' hunk of 80 grit sandpaper around a 1/8'
drill bit and held it in place with masking tape at
the bottom. The next time I went soaring I was armed
with my sandpaper roll and a battery operater drill.
Yep, I stuck it in the forward lift fitting hole and
gave it a good 20 second blast while holding forward
pressure and slowely moving it in and out, making sure
to hold it at 90 degrees to the root rib (did the same
with the aft hole while holding aft pressure) WHALLA,
my ship now goes together without any cursing!
Cheers,
JJ
At 15:48 01 August 2007, Mmartin Via Aviationkb.Com
>>>I've read all the posts, several times, regarding mylar
>>>seal replacemate. My
>>[quoted text clipped - 7 lines]
>>>
>>>mmartin
>
>--
>Message posted via AviationKB.com
>http://www.aviationkb.com/Uwe/Forums.aspx/soaring/200708/1
>
>
Ray Lovinggood
tackle. Hopefully, this coming weekend.
Ray Lovinggood
Carrboro, North Carolina, USA
LS1-d(t) (when the mylar is loose and buzzing in the
breeze!)
Ian
> I've read all the posts, several times, regarding mylar seal replacemate. My
> LS3-A needs the seals replaced and am considering doing the job myself. Is
> this something a reasonabley compitent person can do on his own, or should
> this be left to a pro? Your input would be appreciated.
Our LS3a has internal seals, which will need replacing soon, and no mylar.
Which is the best way to go, internal seals or mylar (or both) and why?
My gut feel is that the airfoil wont benefit much from mylar provided that
the hinge gap is sealed to prevent air leakage from the lower to upper
surface - as is the case with internal seals.
We also use a textured duct tape on the lower (hinge) side of the joint. I
presume with mylar, the hinge tape would fall away.
There is currently some "raised bump" (zig-zag like) tape just upwind of
the joint on the underside. I doubt this helps and if it does, the
textured hing tape should have the same effect. We will probably take off
the bump tape when we do the hing seals again.
But how much work is install internal seals verses mylar?
Thanks
Ian
John Sinclair
It is my humble opinion that all you need is mylar!
I believe this because my Nimbus 3 was exactly the
same as another local Nimbus 3, I mean exactly the
same...........same climb, same cruise. I could even
tell the difference in a couple of extra gallons of
water. My internal seals were wearing out, so I just
pulled them out without removing the controls and replaced
them with mylar. Guess what? No change in the ships
performance!!!
I'd cover the hinge gaps on your LS-3 with little pieces
of mylar on the flaps and ailerons (look at a ASW-27)
they did a meticulous job installing mylar. Then select
mylar that just touches the control surface and doesn't
go any further. If the mylar is lifted when control
in moved, you will get increased stick pressure and
it would be a shame to lose the light stick your LS-3
has.
I have seen teflon tape that covers the lower gap with
mylar over the teflon. I don't believe it is necessary.
Don't know if zig-zag works on the LS-3, anybody got
performance feedback on that?
JJ
At 10:06 08 August 2007, Ian wrote:
>On Sun, 29 Jul 2007 17:41:26 +0000, mmartin via AviationKB.com
>wrote:
>
>> I've read all the posts, several times, regarding
>>mylar seal replacemate. My
>> LS3-A needs the seals replaced and am considering
>>doing the job myself. Is
>> this something a reasonabley compitent person can
>>do on his own, or should
>> this be left to a pro? Your input would be appreciated.
>
Ian
Thanks for your input.
On Wed, 08 Aug 2007 13:29:26 +0000, John Sinclair wrote:
> I'd cover the hinge gaps on your LS-3 with little pieces
> of mylar on the flaps and ailerons (look at a ASW-27)
> they did a meticulous job installing mylar. Then select
> mylar that just touches the control surface and doesn't
> go any further. If the mylar is lifted when control
> in moved, you will get increased stick pressure and
> it would be a shame to lose the light stick your LS-3
> has.
This sounds tricky, I must have a good look at a 27. I am not sure how to
get mylar to cover the gap but not bend when the surfaces are moved. And
as you point out, while the LS3a has not got the best performance it has
got lightest controls! I am sure it would be much easier to mess up the
control feel with mylar than it would be to increase the performance.
What is the relative work in fitting and maintaining mylar verses internal
seals?
Maybe we should just use hinge tape on its own. Lots of work to replace
every season, but possibly as effective as the other options.
> Don't know if zig-zag works on the LS-3, anybody got performance
> feedback on that?
Ours was fitted by the previous owner. I doubt it has any benefit.
Thanks
Ian
John Sinclair
>I am not sure how to
>get mylar to cover the gap but not bend when the surfaces
>are moved.
Short strips of mylar are secured to the control surface
in order to cover the hinge gaps, then the wing mounted
mylar rubs on the control mylar......look at a 27.
>Maybe we should just use hinge tape on its own. Lots
>of work to replace
>every season, but possibly as effective as the other
>options.
Teflon gap tape will last for several years. Be sure
to install with control in fully deflected position
+ a tad of a dimple into the hinge line or shrinkage
will restrict the movement.
Cheers,
JJ
Eric Greenwell
> I'm following this thread with interest. I've had
> problems with mylar not sticking to the double sided
> tape. The tape sticks quite well to the gel coat,
> but the mylar doesn't want to stay stuck to the double
> sided tape.
>
> I've been accused of having an engine on my glider
> as I pass over the airfield. But it's just that damned
> loose mylar buzzing.
>
> Of course, the hardest part of dealing with mylar is
> getting the old stuff completely removed. The next
> hardest is figuring out how to insure the mylar stays
> stuck to the double sided tape.
I bought mylar from the sailplane dealer with the adhesive already on
the mylar, hoping the people supplying the product knew what they were
doing. So far, so good, after 6 months and 30 or so flights in a variety
of conditions - dry, humid, cold, hot.
--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly
* "Transponders in Sailplanes" http://tinyurl.com/y739x4
* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org
Chip Bearden
> performance feedback on that?
> JJ
Sorry for the late response; just getting caught up after a long trip.
My experience with turbulator tape on my LS-3 back in the mid 80s was
favorable. Testing against XX's Ventus seemed to indicate improvement.
I tried several locations before finding one that worked (no, I don't
recall what the % of chord was). This was pre-mylar, with tape as the
external seal on the flaperon plus the internal teflon-coated fabric
seal.
Chip Bearden
ASW 24 "JB"
USA