Canopy crack repair

Jeff:

I did a google search in rec.aviation.soaring on canopy
crack repair. Its worth reading. Ths stuff you need is
Acrifix, probably available for Tom Knauff or Tim Mara. With
some care, you can do a good job.

Pete



Message 3 in thread
From: Duane Eisenbeiss )
Subject: Canopy Crack Repairs



--
Have a Schweizer 2-32 with two cracks which have been
drilled several times.
The last three state trailer transportation helped one
begin in a new
direction.
Ultimately replacing the canopy. In the mean time, is
there some kind of glue /
kit to fill the plexiglass cracks and drill holes?
***
You can also buy a repair product from Tom Knauff. It works.
Strength is supposed to be about 80% of normal Plexiglas.

Duane

Message 4 in thread
From: Andreas Friedrichs )
Subject: Canopy Crack Repairs

View this article only
Newsgroups: rec.aviation.soaring
Date: 2000-12-13 02:23:29 PST

Hello Michael

We usually take a glue called Acrifix to repair the damages.
You have to scratch
the cracks widely open (more than 90 degrees) from both,
inside and outside the
canopy so that you will have an X - seem when ready. Fill
both sides with Actifix
and let it harden (UV-light induced). Afterwards everything
is like gel-coat
repair, which means sanding and polishing.

Regards,
Andreas

--

Message 5 in thread
From: Wallace Berry )
Subject: Canopy Crack Repairs



Someone once posted a repair method for fixing canopy
cracks. I can't
seem to find it now, but here's the gist of it. I've tried
it and it
works.

First you need to get a product called Acrifix. It is
specifically for
gluing up canopy plastic. There are two types, a one-part
Acrifix and a
two-part Acrifix. I use the one-part type. You can order it
from Knauf
and Grove Soaring Supplies: http://www.eglider.org/. Tim
Mara may have
it at www.wingsandwheels.com as well.

Next, using a small hobby knife (Exacto knife) or dremel
tool, chamfer
the edges of the crack from both sides. You want the edsges
of the
crack to look like this in cross section:

Paint a very thin layer of Acrifix into the crack.
Cellophane tape can
be used to keep it from leaking through the other side. In
any case,
the coat of Acrifix should be as thin as paint. Too thick a
coat will
form bubbles. Let each coat harder several hours or overnight.

Continue building up the layers until the crack is filled
above the
level of the canopy material. Then repeat on the other side.
This
process is tedious and takes several days to do properly.

Once the crack is filled, the resulting ridge of Acrifix is
polished
down using a canopy polishing product like Micromesh or
increasingly
fine grades of sandpaper, starting at 600 grit and ending
with some
sort of canopy polish.

If done correctly, this procedure can make cracks virtually
disappear.
Only a slight optical imperfection will remain.


A quicker alternative is to use a wood plane to shave off a
sliver of
canopy material from the edge of a piece of broken canopy.
Use this
sliver to fill the crack and glue it in place with acrifix.
The repair
is then polished down as above.

Good luck with it, I've got to get back to work and finish
the repairs
on my M200 canopy.

Wally

Message 6 in thread
From: Duane Eisenbeiss )
Subject: Canopy Crack Repairs

View this article only
Newsgroups: rec.aviation.soaring
Date: 2000-12-16 12:35:05 PST


First you need to get a product called Acrifix. It is
specifically for
gluing up canopy plastic.
Let each coat harder several hours or overnight.
This process is tedious and takes several days to do
properly.

********
This product cures by exposure to UV light (sunlight). I
have found that it
will cure in about 1 hour, while outside in bright sunlight.
The less UV,
the slower the curing process. Waiting over night is no
help, no UV, no
curing. A UV lamp would be beneficial.

Duane

Message 7 in thread
From: Frank Herzog )
Subject: Canopy Crack Repairs


Duane is correct: UV cure. But this leaves the hassle of
moving the canopy
in and out of the house waiting for good sunny weather with
the attendant
handling risk. In the electronics industry we used to use
germicidle lamps
which are just a small flourescent tube made with a clear
quartz glass with
no phosphor to absorb the UV. With the replacement of EPROMS
with FLASH
memory theres not much call for this anymore and I couldnt
find a really
cheap one locally so I opted for the next best source: find
an inexpensive
halogen lamp and take off the protective glass cover which
absorbs most of
the UV. A small caution, halogen bulbs are really hot!
there is a fire risk
if you get it to close to any combustibles, particularly
fabric, and
spitting on the bulbs causes them to explode. I found a
cheap package of
three halogen hockey puck style fittings with a power supply
at a local Home
Despot type of hardware store and mounted them on a scrap
lumber frame. The
frame allowed me to position the bulbs about 20cm. away fom
the canopy ,
check that the canopy doesn't get too hot. I thnk the cure
is slower than
direct sunlight but you can leave the canopy sitting in one
place and apply
the next layer at hourly intervals. Bonus, I now have
halogen under shelf
lighting for my computer desk.



You really DON´T need lamps. Storage near a window is
sufficient.

--

Message 10 in thread
From: ULRICH NEUMANN )
Subject: Canopy Crack Repairs

View this article only
Newsgroups: rec.aviation.soaring
Date: 2000-12-24 12:27:03 PST

Several years ago, I had to repair a crack in my Libelle's
canopy. Acrifix
works well - I let it cure by the window.
But just smearing Acrifix over the crack looks horrible. I
think the main
thing about crack repair is the preparation of the seam.
Here is how I did
it:
1: Place a 2" wide clear plastic tape over the crack. This
will protect the
canopy's area to the left and the right of the crack during
the following
operations.
2: Drill a 1mm hole at each end of the crack to keep it from
propagating.
Caution: examine the orientation of the crack. It may not be
perpendicular
to the surface, so the hole may have to be drilled in an
angle and be sure
to really catch the end. Otherwise, it may spread beyond the
repair.
3: Using a Dremel tool and a small ball grinder (dia.
2-3mm), carve out the
crack to halve of the material thickness through the clear
plastic tape.
4: Do not remove tape and clean 'weld-prep' area with
rubbing alcohol.
5: Fill seam with Acrifix and let cure. Over-fill seam
slightly since
Acrifix will shrink slightly as it cures.
6: Repeat procedure from other side of canopy. Be sure to
carve into the
repair material of the first operation.
7: To remove eccess material, use file, fine wet sanding
paper and buffing
compound.
8: Remove plastic tape and buff area with plactic buffing
compound.

My canopy is holding up since more than 10 years now with
minial optical
distorsion. Feel free to contact me, if you have any questions.

Ulrich Neumann
Libelle 'GM'

--

Peter D. Brown
http://home.gci.net/~pdb/
http://groups.yahoo.com/group/akmtnsoaring/