What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

To Sika or Not to Sika? Thoughts

Dbro172

Dbro172

Well Known Member
Im seeking some fresh opinions on whether or not to Sika my Slider.

I've done quite a bit of research and the Sika route acutally seems a bit simpler. The look from the exterior of the canopy is superb. I don't care too much for the look from the inside, mostly due to poorly stricken joints. Im not confident i could do any better on my first shot either.

If anyone knows of some good resolution photos of a really good Sika job from the inside i'd love to see... My reason in favor of not Sika'ing, well, lets face it, I can simply follow the directions then and dont need to buy anything.

Thoughts / Photos?
 
Derek, if you mask both sides of your Sika fillet, tool the joint, then remove the tape. This will result in a smooth bead.
The process seems arduous, but in reality, follow the direction of others, and it will go well.
 
Last edited:
lorne green said:
Derek, if you mask both sides of your Sika fillet, tool the joint, then remove the tape. This will result in a smooth bead.
The process seems arduous, but in reality, follow the direction of others, and it go well.
Click to expand...

So is it like this: Tape everything, scuff, clean, prime, remove tape. Re-tape everything, caulk, tool, remove tape before cured?
 
sika

I tape the canopy with electric tape to get a crisp edge- using it to make a border around the canopy- understand it will be visible when finished- so do your best to make it straight and even- scuff the canopy and frame, clean with the activator, then prime with the black primer- make sure to have good coverage because it will be visible from the outside, put in place with sika- clamp and tool as needed. let cure for several days, slowly remove tape- presto!! sharp edges, neat finish. Looks great from the outside- the scuffed, primered canopy will have a gloss black border just like your car windshield. Caution- the shelf life of the primer will be at most 9 months- not sure what happens to it after that. Try it, you'll like it.
 
My canopy is not a slider; it's a tip-up. So I can't fully answer all your questions. However, I used Sika exclusively and it turned out very nice. I'd do it again in a heartbeat.

The method an earlier post described is how I did it: tape both sides of the fillet, scuff, clean, prime, apply the Sika (I don't see any need to change tape, unless you've damaged it somehow). Then smooth the fillet after applying the Sika (I actually used my finger... worked very well!) and immediately pull the tape before it begins to set. Here's a photo of how the inside fillet turned out:

P1030639%20(Small).JPG


Here's a closeup shot. It's not perfect, but I can live with these results:

P1030640%20(Small).JPG


Here's a shot of the outside, showing how you can achieve a very narrow, very nice-looking fillet. Same technique:

P1030649%20(Small).JPG


I have lots more pictures and discussion about how I did my canopy, starting here: Canopy Installation with SikaFlex
 
i'd take the sika route any day again!

obviously, you learn along the way. could probably do it with half the goo (it's quite heavy) the next time around and it would still be plenty strong.

if you want a nice glossy fillet, the electrical tape on both sides and then forming the bead while "wet" works really well.
the visible edge is really defined by the black primer, not so much by the sika you put on afterwards. so most care must be taken when applying the primer.

sika was also nicely shapeable once it was cured thoroughly and then sanded with a rough 80grit sandpaper. (tipup canopy to canopy frame) however it looses the glossy look and you'll get a somewhat porous, matte surface that needs to be painted.
our painter put on black "car bumper" paint, which holds up very well so far! no chips on the sika yet.

good luck and another vote for sikaflex!

regards,
bernie
 
One can of cleaner and primer are more than enough, unless you leave the cap off and tip over like me:) I know I used more than one tube of the 295UV on the canopy/frame. I'd suggest you get at least 2. I then got another tube of 295UV as my remaining amount expired by the time I got to the windscreen.
 
cjhammes said:
One can of cleaner and primer are more than enough, unless you leave the cap off and tip over like me:) I know I used more than one tube of the 295UV on the canopy/frame. I'd suggest you get at least 2. I then got another tube of 295UV as my remaining amount expired by the time I got to the windscreen.
Click to expand...

Thank you Charlie, straight from the horse's mouth, I like that.:)
 
I guess I'm not the only one who tipped over his can of primer! Dang stuff is expensive, too. As already mentioned, one can of cleaner and one can of primer is probably enough to do 3 or 4 RV canopies. It would be great to get together with another builder who is nearly ready and share the materials to cut costs.

But I would recommend 2 tubes of the SikaFlex product. I used one tube on my tipup canopy (and had a fair amount left over). I'll need to open another one when I do the rear window here very soon.
 
Easy...

Fit canopy as normal with clecoes. Once in position, mask off area where you DON'T want adhesive, and the area that you do, scuff it with sandpaper and clean it up with a cleaner that will not react with canopy. Apply adhesive and clecoe canopy in place. Using your covered finger, put a nice filet in adhesive on the top and bottom of canopy skirt to make it pretty. Pull masking off before adhesive sets up. Double check that everything is right and if it is, wait 24 hours and it will never come off. Make sure you use the fast cure, not the 7 day cure. It is paintable too. I have a piece of canopy attached to a piece of 5" long aluminum tubing, and using pliers and a vice, no one has been able to get it apart.
 
The most common use for 3M 5200 is marine applications below the water line. It is used as a sealer for through hull fittings and such. I would have never thought of using it for a canopy adhesive but I can say from personal experience that is some extremely strong bonding stuff. I recently had to replace a through hull transducer on my boat that had been sealed with 5200 and once I was finally able to extract the old ducer, it brought some of the surrounding gelcoat from the bottom of the boat with it!
 
Flexibilty

Todd assured me Sikaflex was the all the adhesion I would need ( no rivets ) for my RV3 tip up. He said MANY glass EABs use adhesive only successfully.

There have been numerous comments regarding Sika joint thickness to allow some flex for expansion differential. 3M 5200 sounds like it bonds WELL. Is there a flexibility ( expansion accommodation ) parameter we should be aware of ??
 
There is flexibility in 5200, and should be no problem. Todd was the one who told me to use it, and doing research here has shown that it has been used successfully. My brother works for American Airlines, and they use 5200 when they want to bond something permanently.
 
The use of 5200 has come up a number of times. I have used it quite a bit in marine applications. I planned to use the 5200 for the canpoy, but after further research, 3M reccomends that is not be used as sole-means for window attachments. Maybe this is just a liability disclaimer, but they do call for a secondary mechanical fastener.
 
Todd has told me of RVs that have flipped over and shattered the canopies, but the 5200 did not let go. If some one can pull off the scrap piece of canopy from the aluminum tube (5" section), then I will look at adding a mechanical fastener. But everyone that has looked at it (A&Ps, GlasAir builders, etc) has no worries, too include Todd.
 
My experience with 5200 on a sailboat that was stored in a dry area on its trailer, is that after about ten years, it fails. It's environment was Colorado (an arid state), 4 months a year floating on the water and 8 months on its trailer.

It was used in a couple areas as a hull/deck sealant and to bond a copper lightning strip to the inside (water-exposed area) of the gelcoated daggerboard case. Neither area got any direct sunlight.

When I repaired those areas, I learned that the 5200 really, really, flows when applied. It was difficult to apply to a vertical surface. It might be easier to use strictly as a glue between two parts that are held in place during curing, but without that, it was annoyingly difficult.

Dave
 
3m 5200 is what I have attached my canopy on with, not flying yet. It is definitely bonded well. I don't expect to have any problems. Only hole in my canopy is where the latch goes through.

Bird
 
I just assisted

my hanger mate glue back a piece of canopy on his tip up RV-9 at the rear corner screw. Stop drilled the crack and try to put the pieces together again. I have no rivets in my RV-8a canopy or windscreen, just Sika. I wanted to say "I told you so," but he was already in enough pain. Use the Sika and avoid the pain. I would recommend, if you can set it up, to practice the filling and smoothing process because it takes a bit of skill to make it look nice. Best of luck
Bill of Georgia RV-8A Bluebird 99 hrs
 
reading between the lines here....

Michael Henning said:
Fit canopy as normal with clecoes. Once in position, mask off area where you DON'T want adhesive, and the area that you do, scuff it with sandpaper and clean it up with a cleaner that will not react with canopy. Apply adhesive and clecoe canopy in place. Using your covered finger, put a nice filet in adhesive on the top and bottom of canopy skirt to make it pretty. Pull masking off before adhesive sets up. Double check that everything is right and if it is, wait 24 hours and it will never come off. Make sure you use the fast cure, not the 7 day cure. It is paintable too. I have a piece of canopy attached to a piece of 5" long aluminum tubing, and using pliers and a vice, no one has been able to get it apart.
Click to expand...

Beings that you held the canopy in place with Clecos while sealing it, it sounds that you used both sealant and rivets. Is that the case?
 
Dave,

I found it to be quite easy to work with, and that it held a shape quite easily. It is considered by 3M to be a "permanently" bonded surface. My brother, who works for American Airlines, uses it in airports to hold critical surfaces together. I think that if it had a finite life, 3M would not use the term "permanent" and American would not be betting huge law suits if it failed.

Many others have used it on their canopies without any failures. Todds Canopies swears by it as well. Time will tell, but if it starts to become brittle in ten years, it would be an easy fix.
 
Derek,
I did not use any rivets. The clecoes were used only as a temporary clamp. I cut the shanks off of some An-426-4 rivets off to fill the holes. It will drive some spectators crazy trying to figure out how I used solid shank rivets.
 
Sika again

I have built two planes using the sika flex system. The process is as described in earlier posts. I added one more step and that was to paint the black sika to match my grey interior. To summarize the key advantages it is much easier and there is much less of a chance of cracking
 
Many Sikaflex users have installed the plexiglass without drilling their canopies......that's one
of the reasons we use an adhesive/sealant to bond the canopy.
 
On your tip up - How much did you trim of the alu for the rear window ? Did you just trim the skin as per VAN's drawing - or did you leave a larger overlap ?
 
JanRV6UK said:
On your tip up - How much did you trim of the alu for the rear window ? Did you just trim the skin as per VAN's drawing - or did you leave a larger overlap ?
Click to expand...

For me, the rear window overlay (the amount of plexi that comes in contact with the underside of the upper fuse skin) is 1 1/4". With a 1/8" ~ 3/16" Sikaflex gap.
 
You must log in or register to reply here.
Back
Top