utawl

Member
Hi all,

I am about to glue the canopy, Chalkie Stobbart wrote an article about the process, can anybody help me with a reference or a link please. I just chatted to Chalkie he will look this evening for it if I do not come right.

Thank you
 
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I Sika'ed mine, but only before I tested it myself, making samples, fastner and glue samples, from the canopy cut-offs and breaking it. Then I read the Sika Datasheets also myself. When I saw my real life test examples, with Datasheets in hand and others confirming what I saw first hand it was an easier decision for me to go the Sika route. It is one of the least things I worry about on my plane.

It is under the Articles/Technical section.
http://www.rvclubsa.com/

Regards
Rudi


Also look in Sport Aviation January 2004................

Warren
 
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Another Quote......

Jim Ellis
Sikaflex 295UV, cleaner and primer

The following describes the process I used for gluing (and bolting) the canopy to the tip up frame on my RV9-A.
You will need two 10.3 fl oz. tubes of Sikaflex 295UV Adhesive, one 250 ml bottle of Sika-Cleaner 226, and one 250 ml bottle of Sika Primer-209N. These can be obtained from Jamestown Distributors.
You will also need some mineral spirits (paint thinner) for cleanup of the uncured adhesive. Once it cures nothing seems to dissolve it. Also buy lots and lots of masking tape. Cheap vinyl electrical tape from Ace Hardware is good to use because it removes without tearing.

Drill #40 pilot holes for the 14 bolts through each of the side frames, but do not drill through the Plexiglas or the side skirts. All twenty-eight side frame bolts may, in fact, not be necessary. The bond that the Sikaflex creates between the plastic and the aluminum is incredibly strong. The plastic will break or the aluminum will bend before the bond will let go. However, the bolts assure that the plastic and frame will stay together even if the adhesive were to fail.
Make eight "U" shaped clamps, four for each side, from 2" x 4" x 1/8" wall thickness aluminum tubing by cutting one of the 2" sides off the tubing and threading a 5/16 bolt into one of the 4" sides of the tubing. Each clamp is about three inches long and sits under the frame with the open end of the "U" facing up. Note the small 3/4 inch thick wood block attached to each clamp which allows the clamp to wrap around the bottom flange and press against the inside of the frame. 2x4 rectangular aluminum tubing is a fairly common item found at metal supply houses. They may even have a two foot long cut-off piece they will give you.
Fit the canopy to the frame. Place three or four rubber hose washers under and along the forward edge of the canopy and three or four washers between the plastic and the canopy bow frame while trimming and aligning the canopy in order to assure a 1/8" to 3/16" gap between the Plexiglas and the metal. Using the washers will assure that not too much is trimmed from the sides.
If you have not done so already, this would be a good time to paint the glare shield area of the tip-up canopy forward skin before proceeding.
The forward and aft edges of the plastic need to be prepared for the adhesive before clamping the plastic to the frame. Mask the front edge of the Plexiglas with a 1" wide edge band on both the inside and the outside. Rough the plastic with red scotchbrite pad, clean and prime. Do the same thing with aft edge of plastic canopy, but make the adhesion band 2" wide on the inside only. The total width of the black primered area over the roll bar and canopy bow is three inches, two inches on the tilt up portion and one inch on the aft window.
After preparing the contact area of both the side frames and the Plexiglas with Sika cleaner and Sika primer apply a layer of Sikaflex 295UV to the side frame. With the canopy in its final position, with all of the washer/spacers in place, tighten the "U" clamps to hold the Plexiglas sides to the frame. Run short 3" or 4" beads of Sikflex along the front edge of the plastic skipping the places where the washers are located. Do not apply too much. You can fill in the gaps and build up additional thickness later. Do the same thing along the forward side of the canopy frame bow. You will have to climb in through the rear window opening to do this...or find a small volunteer!
Wait at least 24 hours before removing the clamps and opening the canopy. Remove the hose washers and run a solid bead of Sikaflex on the inside and outside of the forward edge and along the fore and aft sides of the canopy frame bow. BoatersWorld sells eight inch flexible caulking tips, Item #366981405, that screw onto the Sikaflex cartridge that make applying the adhesive to the gap between the lower inside forward edge of the canopy and the glare shield much easier.
After allowing all the new adhesive to set, back drill the previously drilled pilot holes in the side frame through the Plexiglas with a #40 plastic drill, countersink the outside of the Plexiglas for a #6 AN507-6R8 machine screw, and then ream or drill #27 through both the side frame and the Plexiglas for bolt clearance. Special drill bits for Plexiglas in both fractional and number sizes are available from Abbeon Cal, Inc.
Lightly bolt the canopy sides to the frame as shown in the plans (but not through the side skirts). Tighten the nuts just enough so that the bolts can still be turned easily with a screw driver. Pilot drill the side skirts for only the rivet holes, not the bolt holes, as shown in the plans. Clamp the skirts to the side frames, match drill into the frame and dimple the skirts/countersink the frame. Mask and prep the outboard edge of the plastic and the side frames. Place a thin layer of Sikafex (Non-structural, so thin is okay in this instance.) on the outboard surface of the frame and Plexiglas and clamp the side skirt in place with clecos until the adhesive cures.
Finally rivet the side skirts to the frame.
You should be able to squeeze all but the aft three or four rivets with a longeron yoke. These may to be set with gun and bucking bar. Clamp the canopy frame to the main longeron while riveting in order to reduce the vibration stress on the Plexiglas.
The forward fairing is molded with additional Sikaflex adhesive and sanded to shape with 120 grit sandpaper. If you want to paint the fairing, (a good idea to improve the UV protection for the Sikaflex) wait at least one week for the Sikaflex to fully cure. Do not use a mineral based paint. It will not dry properly. Instead use a polyurethane or water based enamel.
Note that the forward edge of the rear window is bonded to the roll bar, but the aft edge of the window is attached with machine screws per the plans. This was done because it is very hard to hold the minimum adhesive thickness of 1/8 inch required for the Sikaflex. Silicone sealant can be used here to waterproof the joint between the plexiglass and the metal.