VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.


Go Back   VAF Forums > Model Specific > RV-10
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 08-19-2021, 06:28 AM
Lynnb's Avatar
Lynnb Lynnb is offline
 
Join Date: Jan 2014
Location: Cedar Hill, TX
Posts: 342
Default Front Windscreen Unbonded at top

Well I'm looking for some suggestions, been happily flying along for 100 hours now when this morning I was cleaning the front window and noticed a section at the top that flexed a little. Well upon closer inspection I realized there is about a 10 inch section that has come unbonded. Here's a little video of it:
https://youtu.be/8QgYgjnWus4

I installed the windows with Lord Adhesive. I originally had an issue with some of the adhesive not curing on one of the rear side windows, I'm not sure if this is a similier issue or just what, but I'm looking for suggestions on re-bonding. On the fortunate side I'm not painted yet. I know someone will say I needed to glass in the windows, but was planning to let the paint shop do that work.

Any thoughts? This has been a deflating morning to say the least.

Lynn
__________________
RV-10
First Flight 12-17-2020
Reply With Quote
  #2  
Old 08-19-2021, 07:12 AM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
Posts: 6,537
Default

You are quite fortunate to find this before paint. I would definitely pull it, as it is likely there are more areas of poor adhesion. With appropriate care taken, you should be able to get all of the adhesive off the acrylic and F/G. Just be sure to sand aggressively to be sure all of the old adhesive is gone. I would start with razor blades or exacto knife, then chemicals (starting with mineral spirits), then to sanding once all visible traces of adhesive are gone. The acrylic is a 1/4" thick, so you have a bit of margin to scrape off trace amounts.

You may want to consider sikaflex to re-bond it, as there is no mixing involved and therefore lower chances of a repeat failure, guessing that the issue was improper proportions of the two parts due to issues in the mixing nozzle or the twin pump gun. The downside to prepackaged two part tubes, is that manufacturing issues, such as a large air bubble, are difficult to notice by the untrained observer.

I would call Lord to see if heat may help with removal, as you are likely going to struggle to get blades into the joint when separating the windscreen. Some research should help you find unique shaped blades that will help.

Glassing in the bottom of the window is mostly a cosmetic exercise, as the epoxy has a very weak bond to acrylic and only marginally better bond to aluminum. I am certain that it helps hold the window rigidly in it's place, but suspect that 95% of what is keeping it from departing the aircraft is the adhesive bond to the F/G on the sides and top, as those adhesives DO have a strong bond to acrylic. Glassing in the sides and top is purely cosmetic.

Larry
__________________
N64LR - RV-6A / IO-320, Flying as of 8/2015
N11LR - RV-10, Flying as of 12/2019

Last edited by lr172 : 08-19-2021 at 07:39 AM.
Reply With Quote
  #3  
Old 08-19-2021, 08:03 AM
Kyle Boatright Kyle Boatright is offline
 
Join Date: Aug 2005
Location: Atlanta, GA
Posts: 4,626
Default

Quote:
Originally Posted by lr172 View Post

Glassing in the window is mostly a cosmetic exercise, as the epoxy has a very weak bond to acrylic and only marginally better bond to aluminum.

Larry
On the windshield of a -10, glassing in the windshield gives you a fiberglass lip that is bonded to the fiberglass top across the top and two sides of the windscreen. It *should* be a robust capture mechanism for the windscreen.
__________________
Kyle Boatright
Marietta, GA
2001 RV-6 N46KB
2019(?) RV-10
Reply With Quote
  #4  
Old 08-19-2021, 08:48 AM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
Posts: 6,537
Default

Quote:
Originally Posted by Kyle Boatright View Post
On the windshield of a -10, glassing in the windshield gives you a fiberglass lip that is bonded to the fiberglass top across the top and two sides of the windscreen. It *should* be a robust capture mechanism for the windscreen.
I wouldn't disagree with that. However it is a very small and thin piece of F/G extending over the acrylic and I highly doubt it would hold that acrylic in place if the adhesive let go. Not saying it may not help, but I still believe that the adhesive must be robust to keep the windshield in place. I don't think I would trust that little lip to hold my acrylic in place at 200 MPH. Just guessing here, as I am not a structural engineer.
__________________
N64LR - RV-6A / IO-320, Flying as of 8/2015
N11LR - RV-10, Flying as of 12/2019

Last edited by lr172 : 08-19-2021 at 08:54 AM.
Reply With Quote
  #5  
Old 08-19-2021, 08:52 AM
Bill Boyd's Avatar
Bill Boyd Bill Boyd is offline
 
Join Date: Sep 2006
Location: Landing field "12VA"
Posts: 1,684
Default

If you're taking the windscreen out, then it's not too late to consider the SilPruf method.

No fiberglassing over the acrylic is necessary or desirable with that route. Not aware of any failures to date, either.
__________________
Bill Boyd

Hop-Along Aerodrome (12VA)
RV-6A - N30YD - Built '98 / sold '20
RV-10 - N130YD - 50 hours +
65 years running stock DNA
Reply With Quote
  #6  
Old 08-19-2021, 09:30 AM
Ralph Inkster Ralph Inkster is offline
 
Join Date: Feb 2008
Location: Calgary, Alberta
Posts: 1,531
Default

Had this happen to me in a 6 I was ferrying. Scared the s—- out of me as it sounded like an air raid siren went off 3” from my ears as it vibrated in the airstream.
The fairing delaminated the whole length of the roll bar so I was able to flex it forward and locate the screw holes in the plexi, remove every second one, drill & countersink the fairing for longer screws that would go through the fairing/plexi/roll bar. A light film of PRC was applied between, than screwed down. Solved the Screaming Demon.

I’ve used a variation of this method on all my w/shield fairings since.

I just realized your delamination was on a 10. My comments above are more appropriate to 2 place sliders…
__________________
Ralph
built a few RVs, rebuilt a few more, hot rodded more, & maintained/updated a big bunch more

Last edited by Ralph Inkster : 08-19-2021 at 10:22 AM.
Reply With Quote
  #7  
Old 08-19-2021, 09:51 AM
Carl Froehlich's Avatar
Carl Froehlich Carl Froehlich is offline
 
Join Date: Dec 2007
Location: Dogwood Airpark (VA42)
Posts: 3,174
Default

Iím guessing it would be challenging to remove the glass without destroying it. If you can, then starting over would be the preferred approach. If not, then your fix it in place options are limited.

For me Iíd add a couple of bids of carbon fiber over the glass, top and sides. Steps needed:
- Do whatever you can to clean out the existing gap between the glass and the cabin top.
- Figure out how to get the glass to lay flat on the cabin lip. Iím guessing injection of some adhesive then some weights while it sets.
- Tape off the glass so that you only have the cabin top lip showing through the glass along the edges.
- Sand the glass lip, and a couple of inches aft on the cabin top with 80 grit or so paper.
- Fill the gap between the gap with micro, let it set then sand flush.
- Lay up two bids of carbon over the area, keep it just shy of the tape on the glass. Add peal-ply over the layup and let it set.
- Apply a skim coat of micro over the layup and onto the cabin top. Let it set and then sand to feather in the overlay with the cabin top.

The follow up will be to see if you have the same problem on the door or side glass. If so, fix it before paint.

I did this approach on my first RV-10 as almost every RV-10 I saw that followed the instructions (like it seems you did) had ďwindow framingĒ - a perfect crack all around the window where the gap was just filled in with micro before paint. The plane has been flying now for 10 years and has not suffered the same fate.

For the current RV-10 build Iím still debating between this tried and true approach or the Silpruf methods that seems to be popular.

Carl
Reply With Quote
  #8  
Old 08-19-2021, 10:02 AM
Lynnb's Avatar
Lynnb Lynnb is offline
 
Join Date: Jan 2014
Location: Cedar Hill, TX
Posts: 342
Default

Thanks for all the comments, keep them coming. I sent to same question to Van's, right now I'm just trying to build up the motivation to start working on this. Guess it's true the building and maintence never end.

Lynn
__________________
RV-10
First Flight 12-17-2020
Reply With Quote
  #9  
Old 08-19-2021, 12:05 PM
BigD BigD is offline
 
Join Date: Jul 2012
Location: MS
Posts: 326
Default

Using the cabin top/windscreen as a mold, I laid up what I subsequently called an eyebrow panel. This was bonded to the top area of the canopy bow (I used West G Flex) and then the panel, windscreen edge, and windscreen flange were match drilled. Small bolts/washers/locknuts completed the belt and suspenders attachment. The holes were slightly larger than the bolt shank to allow some slight movement.

Click image for larger version

Name:	Pic3.JPG
Views:	89
Size:	747.4 KB
ID:	14818

Click image for larger version

Name:	Pic9a.JPG
Views:	95
Size:	553.3 KB
ID:	14819

Click image for larger version

Name:	Pic9.JPG
Views:	96
Size:	796.1 KB
ID:	14816

==dave==
N102FM
Reply With Quote
  #10  
Old 08-19-2021, 12:37 PM
Lynnb's Avatar
Lynnb Lynnb is offline
 
Join Date: Jan 2014
Location: Cedar Hill, TX
Posts: 342
Default

Well I heard back from Van's and they suggested injecting some adhesive underneath it to stabalize that area, then layer glass on top. So I think I'll start with that approach for now and see where it gets me. I need to get a pin behind the windscreen and see if the adhesive in that area is still goey, that's what I had on the back window when it never cured.

Thanks for all comments,
Lynn
__________________
RV-10
First Flight 12-17-2020
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 04:55 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.