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May
4 - 28, 2007 (5 hrs): We had another
warm day so I decided it was time to make the BIG CUT.
I put the frame back into the canopy and marked a line 3/16" forward of
the front canopy bow. I then peeled back the plastic and laid
down a line of masking tape on each side of the cut line. I also
ran some duct tape across the bottom of the canopy opening in several
places to hold the whole thing together once it was cut in two.
With the canopy laying atop a few 2x4s I began cutting with the Van's
supplied cut off wheel. I started the cuts along the bottom sides
and slowly cut each side a little bit at a time until the cut reach in
the middle. Every 4 inches or so I would stop and apply a piece of
duct tape across the cut line to provide additional support.
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Here is another shot of the entire canopy
during the cut process. |
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Wala, the canopy is in two and no chipped
edges.
I immediately rounded off all the corners and sanded everything
smooth. |
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Temporarily layed the windscreen into
position to get it out of the way. This still needs a lot of
trimming |
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Because I will be using glue to attach the
canopy to the frame instead of rivets, I need to create some spacing
between the frame and the canopy to allow for an adequate glue bead
line. I am shooting for 3/16" gap and borrowed a technique from
another builder of using hose washers to achieve this spacing. Why
glue you say? Well, there have been numerous reports of canopies
cracking along the rivet or screws that attach them to the frame.
The thermal expansion of the plexi-glass is much greater than that of
steal, so gluing should allow for this expansion without any cracking.
Here I have cut the hose washers open and placed them every 4" along
the frame. You don't want any near the bottom sides because the
glass needs to tuck in close to the frame for the skirts to look right. |
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Here is a closer shot of the hose washers. |
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Placed the frame with spacers in the
canopy and clamped things up. I can now mark the canopy cut lines
along the side rails. |
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June 1 - 24, 2007 (5 hrs): Spent some
time checking my measurements for the final cuts on the canopy sides.
After making the cuts, the edges were sanded round and smooth.
The canopy frame was also sanded clean with a
ScotchBrite pad. I then used electrical tape to mask the area that
I did not want sealant applied. This can be seen in the picture.
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I spent a lot of time measuring and laying
down electrical tape to mask the area next to where the sealant would be
applied. For the front, center and side role bars I went with an 1
1/4" spacing for the sealant. The area to be glued was then
roughened with a ScotchBrite pad. |
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SIKAFLEX 226 CLEANER was applied to the
canopy frame followed by SIKAFLEX 209- PRIMER. Next, the hose
washers were placed into position to provide a gape of 3/16" during the
gluing process. Once the primer is applied, it is suggested by the
manufacturer to apply the sealant within 2 hours. |
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Sikaflex cleaner and primer was also
applied to the canopy. |
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The frame was then placed into the canopy
and clamped into position. The sides of the canopy received a bead
of SIKAFLEX 295 UV SEALANT prior to being clamped. Sealant was applied
everywhere else by forcing a bead of the adhesive into the space between
the frame and canopy. I let this cure for 12 hours and then
removed the clamps. The hose washer spacers were removed by
pulling on them with some needle nose pliers. They generally slide
right out. Next, I applied a new coat of the SIKAFLEX 209- PRIMER
right over the existing adhesive bead and voids created by the hose
washer spacers. This was then followed by the application of
another bead of SIKAFLEX 295 UV SEALANT to all areas. A popsicle
stick was then used to smooth out all the beads and make things look
nice. Lastly, I pulled off all the electrical tape that was
masking the surfaces. |
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Here the canopy is placed onto the
fuselage (mainly to get it out of the way) to finish the curing process.
Per Vans and other builders, I did notice that the canopy seemed to have
widened. I did not have time to check the dimensional change
because I was heading out of town on business. When I get back, I
will verify and adjust the canopy fit. I will also look at cutting
and fitting the windscreen. |
