|
-
POSTING RULES

-
Donate yearly (please).
-
Advertise in here!
-
Today's Posts
|
Insert Pics
|

04-24-2019, 08:40 PM
|
|
|
|
Join Date: Nov 2014
Location: Marco Island, FL
Posts: 105
|
|
Windshield Installation (Sika Process)
I have completed my canopy using the Sika process and I am moving on to the windshield. I have viewed several builders web sites and I have searched this forum and the web for instruction, but I still have several important questions that I could sure use some help with.
My plan is to attach the windshield with spacers to the roll bar and the forward deck with primer and Sika, then allow to cure before attempting to draw the sides in and gluing them.
The attachment of the windshield to the roll bar is identical to the process used on the canopy to its frame. The use of spacers and back filling with Sika is easy enough on the roll bar, but I am unsure of what is necessary for the forward section and eventually, the sides.
The Sika process seems to demand that there be a gap between the two primered surfaces for proper adhesion. I suppose that a small gap can be set for the forward section where the windshield attaches to the front deck. The forward section of the windshield will be primed on both sides for perhaps a 1/2? strip and Sika then applied with a continuous bead to both sides. (It may be that no gap is necessary in this case. I am unsure. For that matter, the forward section could simply be held in place by the fiberglass laminate.)
Considering that the windshield is fast at the roll bar and the forward section, the bulging sides need to be addressed. If the sides are to lay flush and be faired seamlessly without an obvious bulge, spacers cannot be used. How to apply the Sika? Do I prime the inside of the windshield sides and the fuselage and then simply inject Sika or smear it into the gap before clamping down? For that matter, if the roll bar and forward section is fast, can I eliminate the side bulge at all?
As you can tell, I am a little lost here and I need some direction from someone who has successfully accomplished this. It may be that I am making very incorrect assumptions and not attacking this properly at all.
Thanks for any help.
__________________
RV-9A
Will fly in the Spring of 2019
Dues paid annually (and very thankful for this site)
|

04-25-2019, 05:09 AM
|
|
|
|
Join Date: Nov 2015
Location: neustadt ontario
Posts: 118
|
|
I did as you are doing. I used temporary clips held with clecos to hold the front and sides. I primed and applied sika and skipped the clips. I ground the windscreen to a taper with a belt sander first to allow a larger surface. The point of the screen touches the metal. This method removes the bulge the first pass. Next day remove clips and apply sikaflex to the small areas left.
When dry I trimmed with a sharp knife the sticky outy bits. Then fibreglass over the joint. Mine has not flown yet but appears to be solid.
|

04-25-2019, 06:37 AM
|
|
|
|
Join Date: Nov 2014
Location: Marco Island, FL
Posts: 105
|
|
I gather that you used the belt sander on the entire forward edge, including the sides. I am afraid to death of the belt sander. What grit paper did you use? How wide was the final finished edge? Did you polish the edge to prevent stress cracking?
I am surprised that the clips would hold in the sides. I have not tried pulling the sides all the way in yet, but my first attempt would indicate that the amount of pressure required would be significant. I see that others have used a 2 x 4 and big clamps.
I assume that you primed the roll bar, inside of windshield and the fuselage in advance. Did you place a bead of Sika onto the entire inside (primed) windshield edge (except for the roll bar area) and then place the windshield on the plane and clamp down? (This would probably have to be accomplished very carefully by two people.) Otherwise, you could only add the Sika by injecting a bead from the inside of the cabin, which would be a little difficult.
I am also assuming that you did not use spacers along the windshield forward and side edges since you mention that the point of the windshield touched the metal. I would guess that you relied on the gap behind the ?point? to supply that requirement.
In truth, it might be debatable that the forward edge and sides need to be glued at all since you are holding them in place with a considerable epoxy/glass laminate, correct? The Sika gives you additional assurance and perhaps some flexibility.
Am I understanding correctly? (Thanks so much for your help.)
__________________
RV-9A
Will fly in the Spring of 2019
Dues paid annually (and very thankful for this site)
|

04-25-2019, 07:20 AM
|
 |
|
|
Join Date: Oct 2005
Location: 08A
Posts: 9,500
|
|
If the epoxy/fiberglass fairing is actually bonded to the plexiglass, the Sika adhesive does little or nothing structural along the bottom of the windscreen.
The edges of the plexiglass should be rounded, and sanded/polished to a fine finish, i.e. as near to polished as possible.
__________________
Dan Horton
RV-8 SS
Barrett IO-390
|

04-25-2019, 08:32 AM
|
|
|
|
Join Date: Nov 2014
Location: Marco Island, FL
Posts: 105
|
|
Dan,
I agree with you. The edges need to be polished smooth so as to avoid any future stress cracking, but I still don?t know how to adhere the sides. I can clip the forward edge without much difficulty and I can Sika Flex the windshield at the roll bar easily enough. The sides, however, would seem to be a problem. I am not sure that they can be held in with clips and a 2 x 4 bracing system would interfere with the laminating process.
Any suggestions?
I wonder if it would be possible to scuff the windshield sides on the interior and scuff the fuselage as well, then epoxy them together? That might be messy and dangerous. Maybe Sika would work using primer on both surfaces, but not using spacers?
Still thinking, but I believe that Sika on the roll bar with spacers and epoxy/glass laminate on the forward area is the way to go. I just don?t know how to attach the sides.
__________________
RV-9A
Will fly in the Spring of 2019
Dues paid annually (and very thankful for this site)
|

04-25-2019, 10:32 AM
|
 |
|
|
Join Date: Oct 2005
Location: 08A
Posts: 9,500
|
|
Quote:
Originally Posted by Jwputnam
.... but I still don’t know how to adhere the sides. I can clip the forward edge without much difficulty and I can Sika Flex the windshield at the roll bar easily enough. The sides, however, would seem to be a problem. I am not sure that they can be held in with clips and a 2 x 4 bracing system would interfere with the laminating process. Any suggestions?
|
Sika vs fiberglass...there are obvious advantages to Sika. My concern is with mixed attachment methods. With Sika, I'd suggest a separate fairing layup which is not epoxied to the the aluminum boot cowl or the plexiglass. After the windshield is installed, cover the area with clear tape, do a fairing layup, pop it off, finish it as desired, and stick it in place later with a bead of sealant or Sika. Now the windshield can expand and contract without constraint, one of the reasons to use Sika.
As for pulling in the sides, some of that is normal. However, be sure you have the front edge trimmed properly. When you pull in the lower rear corners of the windshield, as it would be bonded, is the edge parallel to the roll bar? Is the sliding canopy edge parallel to the roll bar?
__________________
Dan Horton
RV-8 SS
Barrett IO-390
|

04-25-2019, 11:11 AM
|
|
|
|
Join Date: Oct 2013
Location: Schaumburg, IL
Posts: 5,297
|
|
Quote:
Originally Posted by Jwputnam
Dan,
The sides, however, would seem to be a problem. I am not sure that they can be held in with clips and a 2 x 4 bracing system would interfere with the laminating process.
Any suggestions?
|
While different than yours, I just used Sika to install all of the plexi on my 10. I cleco'ed the plexi in place. I used a standard #10 washer under the plexi at each cleco location, along with other strategically placed spacers ( 1/4" squares of aluminum attached with super glue). It works well. If you are cover the area, no need to address the 3/32 holes remaining. If not, you can used the sika flush in the hole and is not really visibly distracting. You wont need many clecos. Just be sure to push out the excess sika to make the plexi where you want it between clecos. The sika isn't very viscous and will cause the plexi to bulge between clecos if you don't push on the plexi to force it out.
As Dan mentioned, the sika will allow the plexi to expand and contact and any f/g fairings over the edges could be problematic. I have already seen the sika bulge to accomodate expansion.
Larry
__________________
N64LR - RV-6A / IO-320, Flying as of 8/2015
N11LR - RV-10, Flying as of 12/2019
Last edited by lr172 : 04-25-2019 at 11:18 AM.
|

04-25-2019, 02:20 PM
|
|
|
|
Join Date: Sep 2005
Posts: 119
|
|
I would fiberglass the front, drill the sides and sand the edges. In my case I Sika Flex the front, drilled the sides and Sika the roll bar. I have the tip up canopy. I believe if I only would have used fiberglass on the front it would have been easier to prepare for paint and finish. Just my two cents.
__________________
Jim Fogarty
RV-9A N-492RV
|

04-25-2019, 02:39 PM
|
|
|
|
Join Date: May 2006
Location: Pocahontas MS
Posts: 3,884
|
|
I did the fillet around the windscreen on my tipup using Sika, with no fiberglass at all. Very easy to sand, using sandpaper wrapped on a large dia PVC pipe. Unfortunately, I can't tell you how it's surviving, because it's back in the crate, waiting on me to finish the rest of the plane...
|

04-25-2019, 03:48 PM
|
 |
|
|
Join Date: Feb 2010
Location: Gardnerville Nv.
Posts: 2,828
|
|
Quote:
Originally Posted by DanH
Sika vs fiberglass...there are obvious advantages to Sika. My concern is with mixed attachment methods. With Sika, I'd suggest a separate fairing layup which is not epoxied to the the aluminum boot cowl or the plexiglass. After the windshield is installed, cover the area with clear tape, do a fairing layup, pop it off, finish it as desired, and stick it in place later with a bead of sealant or Sika. Now the windshield can expand and contract without constraint, one of the reasons to use Sika.
As for pulling in the sides, some of that is normal. However, be sure you have the front edge trimmed properly. When you pull in the lower rear corners of the windshield, as it would be bonded, is the edge parallel to the roll bar? Is the sliding canopy edge parallel to the roll bar?
|
This is how I did mine.
__________________
7A Slider, EFII Angle 360, CS, SJ.
|
| Thread Tools |
Search this Thread |
|
|
|
| Display Modes |
Linear Mode
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
All times are GMT -6. The time now is 03:43 AM.
|