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Broken Canopy Corner

I am building an RV7 with tip-up canopy. While working on the panel, I accidently let the canopy slam down and broke off a 1"x5" corner on the aft RHS of the canopy. Looking for advice on how to fix. I would like to bond the broken piece back in place if practical (the broken edge is very jagged so not sure if this is a good idea). I see that some have used Plastifix. I was planning on doing a "targa" strip, which would hide this area and provide additional support to the cracked area. My questions:

1) Is it feasible to bond the broken piece back in place and how to do it?
2) guidance on how to do a "targa" strip (I'm thinking fiberglass as opposed to an aluminum one)

I will be removing the canopy and storing it (until needed) to prevent any further bonehead moves.

Mark Rinehart
 
Yikes! That makes me ill--I can only imagine how you must have felt.

I would think that bonding the broken piece of Plexiglas would be an exercise in futility, but someone with more experience may weigh in on that. If the break isn't into the screws that hold it to the canopy, you may be able to get away with the targa strip to hide it. A buddy did that on his RV-7; it was made out of 0.035" aluminum. But he did it for the appearance and not to hide a break.

It's a compound curve, so you can't just cut a 3" rectangular strip and slap it on. As I recall, he made templates out of poster board taped together until the shape was just right, then transferred that over to a big sheet of aluminum. It's held up well after almost 15 years, and gives a nice, finished look to the canopy.

If you leave the broken edge, be sure to smooth it out so there are no opportunities for cracks to propagate. Two thoughts for you to mull over...I've learned that I have to tell friends to let ME open and close the canopy every time. It is so easy for someone to let that thing drop or come down crooked and risk damaging it. Mine has fallen twice so far, but the D-ring prevented Plexi damage. Had to take the D-ring out and bend it back into shape, but that's a far easier fix than replacing the Plexiglas. The second thing is that making a couple of UHMW guide blocks for the latch pieces to slide down is a good idea. It keeps that corner from getting damaged when it comes down cocked to one side or the other (and it will). There are plenty of examples out there to look at.
 
You have my empathy.
I broke a 2X3 piece out of the aft left corner on a flying tip up -7A years ago. I boded it with a plexiglass specific glue and it has held up. 500 hrs so far.
I’m sorry, but I can’t remember what product I used.
Tip: fab a guide for the latch weldment to eliminate side to side movement in the last few inches of canopy closure. That movement was the cause of my breakage.
 
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I've heard of others repairing Plexiglas with IPS Weld-On #2 or #3, that's what it's designed for. Perhaps someone else who's used it will chime in.

HTH

Dave
 
A friend of mine broke the same side but a bit smaller, maybe around 3" and he bonded it and held with no issues. Weld-on #3 is super thin and does a great job but if it is a clean break. If not a clean break, you might want to try Weld-on #16

Good luck
 
This is no big deal and it happened to me also.

I dressed the cracked edge on the remaining canopy to prevent further cracking and chipping. In my case, the crack was just the corner and didn't protrude any further than the underlying roll bars.

I then laid up a fiberglass targa strip. I didn't bother reattaching the broken off corner. You can't see the cracked corner and I never even think about it any more.

I also installed those guide blocks on the forward surface of the roll bar where the canopy latches come down.

Again, no big deal at all, nothing to lose sleep over.
 

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Please contact Lew Gallagher @ 864-915-1647.Lew is the plexi repair guru. He has repaired several canopies for myself and my friends and it is truly remarkable what he can do. If you can't get the canopy to him, he will talk you thru what he's learned.
 
Targa Strip

Targa strip was no big deal.

-Close up canopy.
-Place clear packing tape over the area you want the fiberglass to go plus a little further. This acts as a mold release. Be sure you lay packing tape below the canopy as well.
-Mask off the canopy and any other areas you don't want resin to drip on
-Cut fiberglass strips about the width of your desired targa strip. I staggered the end to end seams to make it from one side to the other.
-wet the strips with a saran wrap backer to allow you to place the strips onto the canopy
-build up multiple layers in height and width, similar to fiberglassing the front edge of the canopy.
-allow to cure, pop off the strip, sand, fill, and paint.

I attached the targa using silicone and three fasteners. The fasteners were placed on each end of the strip and one in the middle. Attachment was done after paint.
 
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A lesson for other tip up builders.

I am building an RV7 with tip-up canopy. While working on the panel, I accidently let the canopy slam down and broke off a 1"x5" corner on the aft RHS of the canopy. Looking for advice on how to fix. I would like to bond the broken piece back in place if practical (the broken edge is very jagged so not sure if this is a good idea). I see that some have used Plastifix. I was planning on doing a "targa" strip, which would hide this area and provide additional support to the cracked area. My questions:

1) Is it feasible to bond the broken piece back in place and how to do it?
2) guidance on how to do a "targa" strip (I'm thinking fiberglass as opposed to an aluminum one)

I will be removing the canopy and storing it (until needed) to prevent any further bonehead moves.

Mark Rinehart

Sorry for your event Cap.

The lesson for all tip-up builders is to check clearance between the plexiglass and the heavy angle underneath the skin. I noticed this one building day, remembering all the reported corners broken and cutback the plexiglass to ~3/16" clearance on full close. I hit the canopy closing the garage door and it survived. Hard to believe corners are still breaking after 10 yrs.

Sooner or later it will drop hard. Be prepared.
 
This is no big deal and it happened to me also.

I dressed the cracked edge on the remaining canopy to prevent further cracking and chipping. In my case, the crack was just the corner and didn't protrude any further than the underlying roll bars.

I then laid up a fiberglass targa strip. I didn't bother reattaching the broken off corner. You can't see the cracked corner and I never even think about it any more.

I also installed those guide blocks on the forward surface of the roll bar where the canopy latches come down.

Again, no big deal at all, nothing to lose sleep over.

i'd be wary of dressing the edge before you decide how to repair. If you're using the broken off piece and a bonding agent such as weld 3 or Tensol it needs an interference fit as it doesn't "flll" any gaps that might arise from dressing.
As it welds the two contact surfaces together and so long as the bond is complete it should prevent anything propagating.
If you decide to glassfibre the missing piece then dressing definitely needed.
 
Repair

You need acrylic specific product from any commercial plastic shop. Have everything ready to clamp it, some small c clamps and thin wood strips work well. Clean the edges with alcohol. Apply the glue and clamp together. After the glue sets you can sand it smooth with 500 sandpaper transitioning to 1200 and then polish with one of the kits from Spruce etc.
 
I am building an RV7 with tip-up canopy. While working on the panel, I accidently let the canopy slam down and broke off a 1"x5" corner on the aft RHS of the canopy. Looking for advice on how to fix. I would like to bond the broken piece back in place if practical (the broken edge is very jagged so not sure if this is a good idea). I see that some have used Plastifix. I was planning on doing a "targa" strip, which would hide this area and provide additional support to the cracked area. My questions:

1) Is it feasible to bond the broken piece back in place and how to do it?
2) guidance on how to do a "targa" strip (I'm thinking fiberglass as opposed to an aluminum one)

I will be removing the canopy and storing it (until needed) to prevent any further bonehead moves.

Mark Rinehart


Mark, since you have the canopy off the airplane, consider taking it over to Jeff Rogers at Airplane Plastics in Tipp City, OH (about 3+30 in your car/truck from Danville) and get his advice. He’s a very helpful guy (he has an RV), but call first.
Seems to me, although I didn’t see a picture of the damage, that you could cut off that lower corner and make a sort of modified targa with a curve at the bottom that would hide the missing piece. Of course you’ll need to make the targa the same on both sides to make it look like you meant to do it that way. No need to cut out the corner on the other side. I’m pretty sure Jeff would say that this can be fixed.
 
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