About to glue my canopy --- any last words of advice?

I have read some of the excellent writeups on this subject from Mickey and others. My canopy has been cut and trimmed to just below the frame but I left it longer towards to back to facilitate bonding the skirt. I'm using pieces of hose to create the 1/8th in gap and figure on about 30 clamps/spacers to hold it in place.

What I am debating now at the 11th hour is whether to bond the whole canopy in one go except around the spacers so I can get them out and then backfill where the spacers are --- OR as some have suggested, to put about 20-30 "dabs" of adhesive to fix it in place and then go back the next day without spacers and fill it all in with adhesive.

My concern is around the 2 hr limit specified for the primer. For those who have put the dabs on and then gone back did you:

1. prime the whole thing and then just go back ignoring the time limit? I have seen this has been tested and bond strength is lower.
2. prime and then reprime over what was there before finishing the next day?
3. just apply primer for the spot bonding and then apply between the plexi and the frame with a thin brush before finishing the next day?

Any other "latest learnings" appreciated.

I just finished sikaflexing my slider and used hose segments for spacers, glued it up then pulled the spacers and filled the gap. When I do the wind screen I plan to leave the spacers in because it is easier to get a nicer bead the 1st time than it is to come back and fill in. I am very pleased with the results. Best of luck to you!

Tom -

Not sure if you saw my write up - http://www.rv8.ch/files/RV-8CanopyGluingProcedure.pdf

I had some of the same concerns dealing with the ~2 hour time. I came up with a procedure to deal with it. If you have any questions, just send me a PM.

I'm convinced

ericwolf said:

Tom -

Not sure if you saw my write up - http://www.rv8.ch/files/RV-8CanopyGluingProcedure.pdf

I had some of the same concerns dealing with the ~2 hour time. I came up with a procedure to deal with it. If you have any questions, just send me a PM.

Click to expand...

I have been on the fence about gluing the canopy but Eric your instructional write has convinced me. Nice work, I am sure many of us will appreciate you taking the time to write the procedure up and illustrate ti with picture.

I did the complete SIKA injection, then removed the clamps and spacers after it set up and filled in these spots. I noticed that the clamps had left small dimples, or waves if you will, in the plexi. Now these are much less than on riveted canopies I've seen, but the clamps did leave a little spot that is optically visible when you look along the outside of the canopy with the light 'just right'.
If this bothers you, you may consider the small dab method. mine is not visible from inside the cockpit, but there you are, depends on how much of a perfectionist you are.
I did not use any spacers on the windshield where it rests on the forward fuse skin, but I did on the windshield weldament. The expansion of this shape and small size didn't bother me, plus I 'might' glass over it so the slider canopy will fit under a glass tape overlap when it slides forward to the closed position. I didn't want the look of the glass tape, but the seal, and possible aerodynamic lift on the slider may warrent it?

I will be starting the canopy shortly ,I was planning the vans way but I like the throught of bonding it . I operate in very cold temps -40 any throughts on that . Havard

How do you prime after tacking?

Scott,
Your method sounds good, but I have a few questions (I am about to glue my 8A canopy). First, before you tack on the canopy, do you just prime those spots you are going to tack? Also, is it difficult to prime the rest of the canopy and the frame after the canopy has been tacked on? How do you apply the primer? Thanks for your help.

Steve;
I used the segments of garden hose method, which means the whole frame and plexiglass areas to be joined are taped, scuffed, cleaned and primed according to the instructions. The primer was applied with a small paint brush, then back lighted to check for 'hollidays' which I touched up. When you bond the canopy on this way, the small areas not bonded where the spacers are is insignificant, so the spacers are removed when the original bond is sufficiently cured, then you just add SIKA into these small areas. The bond to the 'over cured primer' will still be mighty strong.
It is possible to leave the areas under the spacers unprimed until after the spacers are removed, it would be a lot of fiddley work to rough up, swipe with cleaner, then brush on some primer, but it can be done.
That may be more worthwhile if you are using the 'dab method' to secure the canopy, then apply most of the SIKA later.
I just recall that Chalky's original story about SIKA bonding included a reference to a friend who did not prime his wingshield when he bonded it. After an unfortunate landing whereby the plane flipped; he could not pull the windshield away from the fuse without breaking the plexi. Also one of the MONEX builder's sites had a peel test where the builder is seen hanging from a narrow strip of aluminum SIKA bonded to plexi.
That's an anticdotal story, but you may certainly do your own testing.
If you look at my link below, you can see a few pics of my canopy job, which was very simple. I did it upright with one end on the end of a table and the other on a stool. I just 'went inside' the gap between table and stool, and filled the SIKA joints top and bottom. The open tube ends of the forward canopy frame were set down over clecos, but screws or nails would work as well. Then the canopy won't fall off the table or swing off the stool holding up the tail end. The benefit is that the canopy is fitted upright in the 'normal' position it will be used in, and you can inspect the assembly during and after the proceedure.

thanks for the advice. Some feedback after the deed is done.

I went ahead pretty much as described at the beginning of this thread but can add a few comments and maybe add the the pool of available knowledge.

1. I decided to go with the "tack down" method which basically puts it all together and you remove the spacers before gluing the whole structure.

2. Only the spots glued first are primed because the primer should be bonded within 2-3 hours according to Sika. If not it may become too hard and create problems in the final bond. Having said that the final bond is so good that anyone who didn't follow this advice will probably get away with it. I didn't want to take the chance.

3. The distributor throws in one brush which is presumedly for the primer. In our application this is pretty useless because of the size. I went down to Michael's Crafts and bought a package of cheap "flat"artist brushes. You really only need about 3/8" and you have to get into the 1/8" gap created by the spacers. I found it impossible to re-use a brush. The primer evaporates and cures very quickly. Just threw them away when finished

4. I put fairly large globs on to "tack" it. Could have been smaller. The bond strength is so good. By large I mean something like half inch to an inch.

5. I considered the double taping mentioned in the suggested procedure by one of the previous posters but found getting the tape on the first time tedius enough. I did my best to have the tape line for the top part of the bonding even with the top of the frame. I would also suggest that when masking the frome that you use two pieces of [electrical] tape. One overlapping the other at the back. Then you can peel one side before the other and bond the inside for example and then go back to the outside without worrying about taking off the tape.

6. One of the biggest plusses of the "tack it first" process is that the next day you can handle the whole assembly. This makes it much easier to complete the priming and to apply the adhesive. There is room but not a lot to manipulate the caulking gun for the top portion. I found it very convenient to just stand the canopy up on the front end and work on it that way.

7. Squeezing the adhesive out of the cartridges I found fairly hard to do with about a quarter inch hole on the plastic nozzle [you must buy separately!] and the largest hole possible in the end of the cartridge.

8. After tacking down the plexi I just used electrical tape over the nozzle and there was no problem coming back the next day --- and I'm in Florida with 90+ deg and high humidity everyday.

9. I just "tooled" the fillets with my finger which was in a surgical glove. Worked fine.

10. There is not a whole lot of time available between applying, tooling and then peeling the masking tape. I used white electrical tape. I would say the after 10 minutes you may find the adhesive coming off with the tape ---- better in other climates with lower humidity / temp.

11. As has been mentioned before any adhesive that finds it's way to other unprimed surfaces rubs off easily with your finger.

12. Like many things on my RV I'm sure I could do it a second time much better. Regardless I thought the result was very good and I'm looking forward to matching up the windshield with spacers and doing the same thing.

13. How much did I use? I used about half the can of primer, the most expensive component --- and have plenty for the windshield left. Probably only a third a can of cleaner and two full cartridges of adhesive --- I bought three and one should do the windshield.

14. Starting with a trimmed canopy it takes around half a day to set it up for "tacking". Maybe a little more depending on how meticulous you are. I used 1 in diameter reinforced hose sold by the foot at Home Depot for the spacers. Forgot to count them but 25+ spring clamps/spacers.


It was a pleasure to not drill any holes and the strength after only tacking the canopy on was enough to convince me. I doubt that Vans will ever endorse this method because it leaves too much the builder could screw up vs the tried and true method. I think it will always be rivets on the plans but that this may become the preferred way to assemble the canopy.