How are those glued canopies

Dear Listers,

This is my first post. Just from reading all the various topics and all your replys have helped me quite a bit in building my RV7 tipup. I've got the canopy cut and trimmed. Just waiting for some warmer weather here in Illinois to do some paint work and then get the canopy attached to the frame.

I have read all the threads I could find on gluing the canopy with Sikaflex.
Have also talked to the tech people at Sika just to get their inputs.
While Sika says you should lay a bead of adhesive in place and then put the part down, that would be a little difficult for what we are using this stuff for.

My questions to people that have used Sika are:

How long have you been flying your airplane and have there been any issues with the Sika joints? Do you do any kind of acrobatics? I plan on lots of loops and rolls when mine is done.

When you applied the adhesive, did you clamp everything in place and then "spot glue" in between the 1/8" spacers, going back later to make a nice solid fillet?

Did you find problems with fit issues, such as attaching the side skirts with the 1/8th inch additional gap needed for the Sika?

I look foward to your replys and a big thanks in advance for your advice.

John

Hi John, and welcome! Good to see another builder in Illinois!

I don't have a tip-up, but I did glue my slider with Sikaflex. I don't have a huge number of hours on it (almost 60), but it is as strong as the day I put it on. I have done aerobatics with it, and I can honestly say that the canopy adhesion has never crossed my mind.

When I glued my canopy, I did just as you described. After everything cured, I did some light sanding of the adhesive to blend things in.

Can't comment on the skirts, since I think your question is specific to tip-ups.

Let me know if you have other questions

Glued canopies @ Pecan Plantation

We have about 6 flying now in our area with no problems. 6's, 7's, 8's and a 9 soon to fly

Welcome to VAF!!!!

John Brunke said:

Dear Listers, ---------

This is my first post.

John

Click to expand...

John, good to have you aboard.

Cant help with the Sika question, but I suspect you will get quite a few responses from those who have used the product.

I've only got 50 hours on mine but I like it fine so far. There have been different ideas on the installation but here is what I did: I fitted the canopy to the frame with spacers on the bow and front deck but drilled to the side rails. No big cut at this time and I made sure the aft skin would fit to the canopy as well. When I was satisfied with the fit, I taped over the roll-over bar and put a bead of sika on the canopy frame bow and a smaller bead on the side rails. Then I put the canopy on and clecoed the side rails. Next, I made a partial fillet on the front deck. Then I crawled inside and smoothed the fillets at the inside of the bow and the deck and cleaned up any excess on the inside from the side rails. I went ahead and installed the screws and keeper strip for the side rails (this, rather than the thin sika, is what I depend on for strength here) and then let it set. A couple of days later I finished the fillet on the outside of the deck (finished is relative; it still needs sanding and I'm planning on a single bid layup to finish it off).

After the sika had set, I lifted the canopy (still no big cut), and taped off the inside where I did not want sika to stick and prepped where it would adhere to the roll-over bar. I then applied a thick bead to the roll-over bar, lowered the canopy again and clecoed the aft skin in place. My intention was to make the big cut after about a week and lift the canopy, but I found that the sika at the cut was still soft and pulled up with the canopy (I was hoping the bead forward of the cut would act as a weather seal). No harm done other than the bead forward of the cut looked rough; it was set completely within another week. I've tried to smooth the exposed bead using RTV but it still looks ugly and I am thinking I will probably just trim it away and replace with weather stripping. It seems to do the job, though, ugly as it is. Once the sika on the roll-over bar had finally set, I riveted the aft skin on, including pop rivets around the aft canopy.

So, as you can see, I did not maintain spacing all around. The front deck had the spacing almost to the side rails and a generous fillet in any case; the bow had the spacing at the top tapering to the side rails (someone mentioned using spacers so the bow could have the spacing all the way down; I didn't think of it at the time); and the side rails and rear skin only have a thin layer backed up with screws/rivets. The exterior side skirts were glued over the screws with sika and riveted to the frame and I made a targa strip over the big cut which helps hide the gluing beneath it as well as acting as additional weather seal. The fillets along the bow are also generous, even down to the rails, and I added a fillet behind the bow after making the big cut. The only other mistake I feel I made was that I had not added the lift struts when I initially fitted my canopy (though they were there when I glued) and I think they were responsible for a little stress crack near the big cut (subsequently repaired and showing no signs of recurring) and a mismatch with the forward deck that required quite a bit of shimming. If I were to do it again, I'd follow the same sequence but I would do the canopy last, after all the avionics were done and the forward deck riveted in place. Also, I'd fit the canopy frame with the struts and locking mechanism before fitting the canopy.

~900 hours of use.
I put a bead down, dropped parts in place including canopy, windscreen, and skirts.
I gave no regard to bead thickness. No clamps.
Sand, clean, prime, bead, drop, go to bed.
I fly it hard.
Been through many temp swings from -20F to 120F.
Hasn't flown off yet.

Just over 100 Hrs in about 1.5 years and no sign of problems with Sika installation. Plane always hangered so only limited exposure to the elements. I used the garden hose washer technique for installation and went back a couple of days later to remove washers and fill in small gaps. This is a 9A installation so no inverted flight.

I have 120 hrs on mine and no problems. It is so much easier not having to drill all those holes in the canopy. I cracked my first one trying to do the traditional approach. Next one I got from Todds and glued it up. I would and will glue my next project also. Care should be taken to keep the glue joints smooth. Mine are a little sloppy and need to dress them up a little. It would have been easier if I had taken more time while the glue was still wet. If you follow the instructions and sand the surfaces and use the primer there is no question in my mind that the glue joint will not fail.
Chad

no worries yet

53 hours, no problems. not allowed to do aerobatics. but it has been through some unusual attitudes, if you know what I mean.

Drilled my first one, sika'ed my second one and I'll never drill another hole in a canopy again!!

So, anyone out there use the Sika products for the windows in a 10???

Would it even work in a fiberglass to plexi joint, or is it something that is specifically designed for metal to plexi???

I am going to be putting in the windows soon--------

Looking for options.

Thanks in advance.

probably Sika for me

I'm about to order my finish kit (9A slider) and am concerned about the drilled canopy. I've cracked every piece of plastic I've ever drilled in my life.

I need to learn more, but I'm leaning towards Sika. I'm hoping Pete Howell will fly down and do it for me!

My only real concern is the powerdercoating issue....

Mike S said:

So, anyone out there use the Sika products for the windows in a 10???

Would it even work in a fiberglass to plexi joint, or is it something that is specifically designed for metal to plexi???

I am going to be putting in the windows soon--------

Looking for options.

Thanks in advance.

Click to expand...

Mike, it works with any prepared surface, according to the tech sheet. There was a thread around here discussing the primer needed to bond to composite vs. metal surfaces. I had the impression that the intended use was to bond plexi windows to fiberglass boat hulls. That said, I'm waiting until I get my RV-10 kit with the shell and windows before I decide how I intend to do the bonding.

Patrick, thanks for the info ----

So as to not hijack this thread, I have started one in the 10 forum.

didnt use sitka

I used Hysol. two parts. read all I could on both sitka and hysol. drilled no holes and It came out great. Cant imagine anything taking it apart. Used/recommended by lancair and showplanes. I dont have the exact hysol # in front of me but can find out if needed

Rob--

That avatar is awesome!! Joel would be proud.

Joe

Thanks Joe! Spaghetti Cat rules!!!!

300 hrs RV-8

I have 300 hrs on my RV-8, all temps, rain and even light snow. Glued with Sika and spacers - then fill in the gaps and form a smooth fillet. I drilled my skirt and used 1/8 inch washers as spacers when glueing. Then pushed out the washers and placed Sika into the gap and into the drilled hole. I have done aerobatics and rapid ascent/descent in large temp changes. My own opinion, but Sika is far better than rivet/screws.

Bruce "FM" Edwards
300 hrs RV-8 N391FM
200hp, WW151, dual Grand Rapids
Back seat single GRT display
Still with RV grin

250hrs, lots of acro, my sika is still rocking on...

In fact, though I've heard many theories - I've never heard of a sika failure.

Can you remove it?

I have a dumb question, can you get it off if you need to replace your canopy for some other reason than cracked screw holes?

Yes,
You can slice with through it with a blade/boxcutter/exacto
Its sands off with sandpaper.

FMF15E said:

I have 300 hrs on my RV-8, all temps, rain and even light snow. Glued with Sika and spacers - then fill in the gaps and form a smooth fillet. I drilled my skirt and used 1/8 inch washers as spacers when glueing. Then pushed out the washers and placed Sika into the gap and into the drilled hole.

Click to expand...

Hi Bruce, I'm not a million miles away (I hope) from sika'ing my canopy. I'm doing a fastback so will need to make custom skirts for it. I don't suppose you have some pictures of your skirts in place with the washers and after washer removal? Do your skirts lay flush or do they sit proud of the canopy now? This is something I don't recall seeing addressed in other posts about sika and I've been wondering how to tackle the skirt fitting.

PS Sorry to hijack, but I'm sure the original poster would also benefit from an answer to this question too

Cheers.

Jeff,

Thanks, but you're not "hijacking" to me. I've picked up a lot of good information so far.
Ordered the Sikaflex a couple of days ago and will get my canopy frame painted today so that I can get this all glued up.

John Brunke

Sika'd my canopy 2 weeks ago. Used a 1/8" spacer on the sides and moved the frame inboard similar to the Swiss guys at flyvans.com so that a .125" bond thickness was achieved along the sides. Adjusted the position of the bow frame so that it sits lower than the rollbar so a minimum of 0.2" of bond was guaranteed all around the bow. I used small rubber spacers to lift the front of the canopy and hold it 0.2" above the glareshield while curing.

Also Sika'd the side skirts to the canopy, and riveted the sideskirts to the spacer. No holes in the canopy at all.

I cured the sika at 50 degrees F, which is right about at the middle of the operating / storage temperature range. Thus positive or negative temperature excursions will result in a minimum of stress in the joint from CTE mismatch. Took a long time to allow cure without disturbing the canopy. Sika's data sheet shows a curve of cure time vs. temperature and relative humidity.

The next one for me will be glued!

My canopy cracked during a trip "Up North" to visit Mom last year. It was 15 above when went to leave and colder at 11,500'. When I landed I found a crack.

How do you space the windshield...

...and canopy to achieve a level relationship with each other? With screws, we added washers here and there as needed, sometimes to the windshield and then to the canopy. We're considering Sika on a -7A going together in my hangar.

Thanks,

hi pierre,

we had a slight mismatch when trimming between the front and the back (tipup).

so we simply cut the front cut to be aligned with the center of the forward flange on the rollover bar, the rear window with the center of the rear flange of the rollover bar. this left a gap of about 1/2" or a little more.

sika has two very nice properties:
- it doesn't stick anywhere where there's no primer, such as electrical tape etc... also if sikaflex gets onto the canopy by itself, don't worry, it won't leave a mark nor stick to it, can be easily rubbed off with the thumb.
- it's very very easy to sand & shape with a 80-120 grit sandpaper once hardened.

so we first glued both the front and the rear into position including the skirts, fillets etc...
then we masked the front canopy rear edge with electrical tape (rear edge and inside the overlap over the rollover bar)
then painted the gap on the rollover bar and the edge of the rear canopy with the sika primer and filled the gap with sikaflex, letting enough goo there to be able to sand it smooth and flush with the rear and front canopy outline later.
during sanding protecting the canopy with duct tape of course.

result is excellent and provides a very smooth transition between the halves!

rgds, bernie

A way to space the skirt for gluing

Hi,

I glued my canopy using the rubber hose spacer method. Then, when time to glue on the skirt, I didn't want a huge gap like 1/8", but I did want to assure a uniform gap and no chance of pinching the glue gap down to zero with clamps. So, what I did was get some 50 lb-test fishing line, about 0.035 diameter IIRC, and I tacked it to the canopy with super glue, about centered in the 1" zone where the skirt bond would be. Then I put on a bead of sikaflex, clamped the skirt in place with some specially made wooden C-clamps, and relied on the embedded nylon line to force a uniform glue bond thickness. Worked great.

Some may worry about the 0.035 bond to the skirt being too thin, but the thermal expansion isn't so different between the plexi and the fiberglass skirt as it is to the metal frame, So I'm comfortable with it. No way is that stuff ever letting go.

The side skirts on mine have a slightly thinner layer of Sika than called for, but they're drilled and riveted to the side of the steel canopy frame (but not through the canopy itself). I put an exagerated inward bend on the piece that supports the plexi on the inside, so it does have the proper bead thickness. Anyway, once that had set, I installed the rear skirt.
I put hose washers on the trailing edge of the canopy. Then, I and my wife (through a few iterations), did the final trimming (fore/aft, not the sides or ends) of the aft canopy skirt. Then once that final trimming of the aft canopy skirt was done, we put down the bead of Sika (on the properly primered surfaces, of course) and, then using duct tape (and an extra set of helping hands) set the aft skirt onto the turtledeck and the side skirts to achieve the best fit. Once the best fit was achieved (so the aft canopy skirt was laying down on the turtledeck well, duct taped in place), I drilled the aft skirts to the side skirts, clecoed it, and came back the next day to final trim the sides of the aft canopy skirts to match the side skirts. So my aft skirt is drilled and riveted onto the side skirts, but not through the plexi. Four years later, the install looks, feels the same. I do think the only downside is a slight increase in weight...if you try to tear off the plexi from the aluminum strips I kept as samples...something will break or tear, but the joint is Mongo tough. Sorry to throw in a little Mel Brooks there, but it's Good Stuff. The trick is, you don't have a lot of working time. Do a lot of prefitting to make sure that at the last minute, you don't have to trim something. Get an extra set of hands, use duct tape liberally, follow the directions and it'll work well.

clever trick

scsmith said:

... So, what I did was get some 50 lb-test fishing line, about 0.035 diameter IIRC, and I tacked it to the canopy with super glue...

Click to expand...

Very clever trick! I'll be stealing it when I do my skirts.

pierre smith said:

...and canopy to achieve a level relationship with each other? With screws, we added washers here and there as needed, sometimes to the windshield and then to the canopy. We're considering Sika on a -7A going together in my hangar.

Click to expand...

I made an assortment of narrow 2024 spacers - mainly to get the recommended bead depth needed by Sika, but adjusted as needed to make the canopy height match the windshield. After the sika was nearly dry, I pulled the spacers out and squirted a litle sika in to fill the gaps where the spacers were.

Skirt Spacing

Greetings
For those that asked about how I glued the skirt: I drilled and clecoed the skirt to the canopy and frame at about the normal spacing called for by Vans with a riveted canopy/skirt. I also split the skirt at the back (RV-8) into 2 parts. When it was time to glue, I put the glue in segments on the skirts and then placed some 1/4" ID washers between the skirt and canopy with a cleco through the hole to hold the skirt as well as the washer against the canopy. When the Sika was nearly dry, I took out the clecos and used a hacksaw blade to push the washers out of the gap. I now had the skirt glued on in segments with the proper spacing and with 1.5" areas that had no Sika. I made a small hole on another Sika dispenser tip and then pumped the glue in through the hole that held the cleco. This filled void and put glue into the drilled hole, through the canopy and into the frame - sort of like a rivet made of glue. I did rivet the lower parts of the skirt to the frame. No problems and rock solid at 300 hours.

Bruce "FM" Edwards
RV-8 391FM
IO -360, triple GRT displays
(one in back seat panel)

What is Vans opinion on glued canopies? Do they give their blessing or leave it to "builder discretion"?

Kelly,

I talked to Ken Krueger at Oshkosh last year. While very diplomatic, Ken would not endorse gluing. Just from a legal standpoint, they have to be very careful endorsing a procedure that is not in their construction manual. We did agree that a surface that can be bonded distributes the stresses more evenly. That was not his endorsement of usiing Sikaflex on the canopies though. Unfortunately in our legalistic society we will probably not get a definitive Yes or No from them.

As more of us use the gluing process, maybe Van's will try it on one of their aircraft.

From their standpoint, drilling holes and using screws are known skills. Each one of us in gluing will use a slightly different variation on amounts of adhesive and the prepping process. From this thread, it seems that Sikaflex is doing a good job of keeping things in place.

John