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219PB

Well Known Member
I have a question on the techniques used to install the plexiglass canopy to the steel frame using the Sika adhesives.

One is to glue the plexiglass onto the steel frame while the frame is mounted on the aircraft.

The other is to carefully layout where the steel frame is in relation to the plexiglass while on the aircraft. Then lay the plexiglass upside down on a carpet table and place the steel frame in it. Clamps are applied and then the adhesive.

Which way has most people used? Pros and cons?
 
I carefully measured the width of the front bow, then drilled holes in a board to hold the front bow at this spacing. Actually, I determined my springbuck would be about 1/4", so I made the holes a little closer. Others have found their springback closer to 1/2".

I then screwed the board between two sawhorse and mounted the canopy frame on it (with a second, undrilled board to hold up the aft end. This gives good access for clamping all around, and I could roll a chair between the sawhorses to work on the inside. I did not try to control the width of the rear bow, as mine was already pretty tight.

Glue up is in two stages, with two layers of tape. The first glue up is narrower, and skips the locations where you have spacers and clamps. Then remove the clamps, reprime, and tool up a final layer of sika.
 
Similar technique

Similar technique to Tom. I got my measurements and used heavy duty ratchet straps to compress the frame so it slid nicely on the frame. Ratchet straps work great BTW. (This was of course after all the bending, tugging, pulling, cussing, throwing stuff) :D

I then mounted the glass on the frame and clamped everything in place and measured the roller distance. Mine sprang out about a half inch or more. I compressed compressed it to a resting span of about 3/4," and called it good. I find it amazing that the frame is so tough but the fragile glass can cause so much movement. A mystery in the life of the build:eek:

Sika'd the thing together and put it on the plane hoping for the best. It was slightly 'over' compressed which was fine. I pulled it out a little and got it sliding perfectly. Much easier to pull out than compress with the glass on. The Sika makes this doable. With fasteners, it could lead to cracks.

Take your time and don't get too worked up on getting the thing absolutely perfect. You'll drive yourself nuts.
 
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