Van's Air Force
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Canopy skirt
- Thread starter Megaulf
- Start date
Stu McCurdy
Well Known Member
Canopy Skirt
Here's what I and several others have done. After drilling and pop riveting the canopy and skirt to the frame, make up a batch of epoxy and flox. Turn the canopy upside down and fill in the crevis on bottom side of frame/skirt intersection as well as front and rear of verticle tubes with the flox mixture. Smooth with finger or popsicle stick. This will bond the skirt/canopy/frame and take stress off of the pop rivets.
Here's what I and several others have done. After drilling and pop riveting the canopy and skirt to the frame, make up a batch of epoxy and flox. Turn the canopy upside down and fill in the crevis on bottom side of frame/skirt intersection as well as front and rear of verticle tubes with the flox mixture. Smooth with finger or popsicle stick. This will bond the skirt/canopy/frame and take stress off of the pop rivets.
redbeardmark
Well Known Member
removing canopy skirt?
I forgot to paint the inside of my canopy skirt before riveting it on. It kind of bugs me and I'm thinking about drilling out the skirt, and installing a new one. But, I worry about the poprivet remnants and the canopy.
Has anyone done this?
Any thoughts?
Thanks,
Mark Andrews N598X flying, but ugly
I forgot to paint the inside of my canopy skirt before riveting it on. It kind of bugs me and I'm thinking about drilling out the skirt, and installing a new one. But, I worry about the poprivet remnants and the canopy.
Has anyone done this?
Any thoughts?
Thanks,
Mark Andrews N598X flying, but ugly
rvpilot
Well Known Member
Check out this link, I glued both the canopy and skirt.
http://www.mstewart.net/michael/rv/rvhome.htm, look under interesting.
Also, you can get with Steve McDonald, he came over and saw it.
Good Luck!
Bill Waters
http://www.mstewart.net/michael/rv/rvhome.htm, look under interesting.
Also, you can get with Steve McDonald, he came over and saw it.
Good Luck!
Bill Waters
Highflight
Well Known Member
Bill,
I also believe that some applications are better served with adhesives rather than rivets, and attaching a plastic canopy to metal framing is one application that begs for such use.
Riveting has obviously worked well, but I am not comfortable with stess concentrations at each rivet hole when you could better distribute that stress evenly over a much larger (bonded) area.
I looked at the specs for SikaFlex and Lexel to see how they would work for canopy installation to the frame, but I also looked at E-6800. Keep in mind that these are all urethane based adhesives (no silicone) but the way they are formulated does make them different from each other.
The short list is:
E-6800 has 8 times more tensile strength than SikaFlex (3500 psi vs. 450 psi) and twice the Shore-A hardness (80 vs. 40) which should mean (I say "should" because I'm not a chemist) that E-6800 is 8 times stronger than SikaFlex (an obvious advantage if I understand correctly).
The big downside to E-6800 is that it has only 5 minutes tack time vs. 50 minutes tack time for SikaFlex.
What that means to me is that you could apply the SikaFlex onto the frame and then install the canopy and wiggle it into position.
But with the E-6800, it would be better to be inside the cockpit with the canopy in position already, and THEN run a bead of E-6800 along the canopy to frame bond area. Then when that's cured, you can take the whole assemble off, turn it upside down, and run a bead on the other side of the frame.
Of course, you'll have to figure out how to get yourself out of the inside of the fuse after running the first (inside) bead... OR just sit there for 24 hours breathing the urethane fumes while it cures.
(Hey, I'm just the idea guy. I'll let someone else figure out the details of the operation).
Another thought is that some people have reported cracking of the fiberglass lay-ups done on the bottom edge of the stationary front wind screen of slider canopies (after some time in service).
So, instead of using epoxy resin and glass cloth, why not instead do that lay-up by saturating (forced squeegeeing) the longer tack-time SikaFlex into the fiberglass roving and use that as the basis for the lay-up.
Once that's hardened, you can come back with a coat of SikaFlex OR E-6800 as a top finish to fare it in and make it smooth. The 80A hardness of the E-6800 especially is enough to lend itself well to priming and painting (it's actually recommended that it BE painted for even better UV protection), but it's not so brittle that it will crack like epoxy fiberglass eventually will because the urethane adhesive will better hold up to vibration and frame twist over time.
Plus, my experience with both epoxy glass resins as well as urethane adhesives has proven to me that if I have to choose between the two, based on how well either will "stick" to a metal surface, the urethane wins hands down.
Just my thoughts on the subject, and I am leaning very heavily toward the idea of bonding, rather than riveting, the canopy sections on my RV7-A slider.
The only concern I have is in how to be able to get a perfect fit without having to force it before bonding.
Of course, whether you bond OR rivet, you don't want to have any built in stress anyway so that's something you have to deal with either way.
I also believe that some applications are better served with adhesives rather than rivets, and attaching a plastic canopy to metal framing is one application that begs for such use.
Riveting has obviously worked well, but I am not comfortable with stess concentrations at each rivet hole when you could better distribute that stress evenly over a much larger (bonded) area.
I looked at the specs for SikaFlex and Lexel to see how they would work for canopy installation to the frame, but I also looked at E-6800. Keep in mind that these are all urethane based adhesives (no silicone) but the way they are formulated does make them different from each other.
The short list is:
E-6800 has 8 times more tensile strength than SikaFlex (3500 psi vs. 450 psi) and twice the Shore-A hardness (80 vs. 40) which should mean (I say "should" because I'm not a chemist) that E-6800 is 8 times stronger than SikaFlex (an obvious advantage if I understand correctly).
The big downside to E-6800 is that it has only 5 minutes tack time vs. 50 minutes tack time for SikaFlex.
What that means to me is that you could apply the SikaFlex onto the frame and then install the canopy and wiggle it into position.
But with the E-6800, it would be better to be inside the cockpit with the canopy in position already, and THEN run a bead of E-6800 along the canopy to frame bond area. Then when that's cured, you can take the whole assemble off, turn it upside down, and run a bead on the other side of the frame.
Of course, you'll have to figure out how to get yourself out of the inside of the fuse after running the first (inside) bead... OR just sit there for 24 hours breathing the urethane fumes while it cures.
(Hey, I'm just the idea guy. I'll let someone else figure out the details of the operation).
Another thought is that some people have reported cracking of the fiberglass lay-ups done on the bottom edge of the stationary front wind screen of slider canopies (after some time in service).
So, instead of using epoxy resin and glass cloth, why not instead do that lay-up by saturating (forced squeegeeing) the longer tack-time SikaFlex into the fiberglass roving and use that as the basis for the lay-up.
Once that's hardened, you can come back with a coat of SikaFlex OR E-6800 as a top finish to fare it in and make it smooth. The 80A hardness of the E-6800 especially is enough to lend itself well to priming and painting (it's actually recommended that it BE painted for even better UV protection), but it's not so brittle that it will crack like epoxy fiberglass eventually will because the urethane adhesive will better hold up to vibration and frame twist over time.
Plus, my experience with both epoxy glass resins as well as urethane adhesives has proven to me that if I have to choose between the two, based on how well either will "stick" to a metal surface, the urethane wins hands down.
Just my thoughts on the subject, and I am leaning very heavily toward the idea of bonding, rather than riveting, the canopy sections on my RV7-A slider.
The only concern I have is in how to be able to get a perfect fit without having to force it before bonding.
Of course, whether you bond OR rivet, you don't want to have any built in stress anyway so that's something you have to deal with either way.
rvpilot
Well Known Member
Canopy Bonding
Vern-
I believe if I'd only had 5 minutes to work with, I'd have been in trouble! It took that long just to get the adhesive on all the canopy frame tubes! The SikaFlex has a good track record where it has been used in this mannor, that is the main reason I chose it. It was also the only one (that I found) which stated in the product description it was used to secure plexiglas to metal, wood or fiberglas.
Achieving a good fit was not a problem for me, as I think the -8 canopy is a little easier than cutting the side by side ones, having done both (and breaking my first one on the -6
).
To address the front fairing problem, I laid mine up on plastic tape, then removed it from the plane. I plan to secure it to the windscreen and plexi using my adhesive and a few strategicly placed rivets, which should give it some flex. I have seen where others have done this fairing in a similart fashion and it seems to have worked out well for them. We''ll see I guess!
Good luck whichever way you decide to go!
BB
Vern-
I believe if I'd only had 5 minutes to work with, I'd have been in trouble! It took that long just to get the adhesive on all the canopy frame tubes! The SikaFlex has a good track record where it has been used in this mannor, that is the main reason I chose it. It was also the only one (that I found) which stated in the product description it was used to secure plexiglas to metal, wood or fiberglas.
Achieving a good fit was not a problem for me, as I think the -8 canopy is a little easier than cutting the side by side ones, having done both (and breaking my first one on the -6
). To address the front fairing problem, I laid mine up on plastic tape, then removed it from the plane. I plan to secure it to the windscreen and plexi using my adhesive and a few strategicly placed rivets, which should give it some flex. I have seen where others have done this fairing in a similart fashion and it seems to have worked out well for them. We''ll see I guess!
Good luck whichever way you decide to go!
BB
kevinh
Well Known Member
I agree on Sikaflex. A couple of years ago there was an article in Sport Aviation on securing RV slider canopies with Sika rather than rivets. I contacted the author using the email address he included in the article. He was quite helpful and sent me _lots_ more info on how to use adhesive to bond an RV canopy.
Within the next two weeks I'll finailly be bonding my RV-7A canopy. Yay!
Kevin
Within the next two weeks I'll finailly be bonding my RV-7A canopy. Yay!
Kevin
greg_gruninger
I'm New Here
canopy skirt: Proseal
I used proseal and rivets to secure my canopy and skirt to the canopy frame. It stays flexible and sticks very well. It doesn't harm the acrylic either. You also can make very nice looking fillets ( I used a popsicle stick to smoothout the fillets) on the outside and the inside of the canopy and skirt. It sands reasonablely well when its fully cured and also accepts paint well. Also, it will completely water proof all joints where used. Just mask off the areas you don't want prosealed and make sure you remove the mask before it fully sets ( within an hour or two).
In regard to painting the inside of the skirt, don't take it off. I painted mine easily by just masking off the canopy. Good luck Greg Gruninger
I used proseal and rivets to secure my canopy and skirt to the canopy frame. It stays flexible and sticks very well. It doesn't harm the acrylic either. You also can make very nice looking fillets ( I used a popsicle stick to smoothout the fillets) on the outside and the inside of the canopy and skirt. It sands reasonablely well when its fully cured and also accepts paint well. Also, it will completely water proof all joints where used. Just mask off the areas you don't want prosealed and make sure you remove the mask before it fully sets ( within an hour or two).
In regard to painting the inside of the skirt, don't take it off. I painted mine easily by just masking off the canopy. Good luck Greg Gruninger
Wicked Stick
Well Known Member
Ok, where do I get/acquire this Sikaflex and what specific type/part numbers are you guys using for the canopy to frame bonding ?
Thanks,
Thanks,
kevinh
Well Known Member
Sikaflex instructions
A couple of years ago Chalkie Roberts wrote a great article for Sport Aviation. If you email him, he will send you a wonderful email thread on how to use Sikaflex to bond a canopy frame. His email address:
[email protected]
I've misplaced my copy of his email - perhaps you can post his reply here? I'll be posting pictures of my Sika install soon.
A couple of years ago Chalkie Roberts wrote a great article for Sport Aviation. If you email him, he will send you a wonderful email thread on how to use Sikaflex to bond a canopy frame. His email address:
[email protected]
I've misplaced my copy of his email - perhaps you can post his reply here? I'll be posting pictures of my Sika install soon.
