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Cracked paint

R

Ron B.

Well Known Member
I had noticed cracked paint arround the windows of quite a few RV-10's, so I tried to followed instructions on here and applied a layer of fiberglass cloth with epoxy over the seam. I was very pleased with the results and it was crack free for a year. We used Weld-on 10 to bond the windows. At Airventure with the canopy cover off for a couple days ( I always like to look inside other aircraft and appreciate not having them covered up) cracks appeared (obviously a big mistake, but I'm sure the same results would have appeared later). I don't know if this is an inevitable occurance without a canopy cover in the hot sun, or if I did not install enough glass. I used one very thin layer,(don't recall it's weight) (still have some left).
Unless this something that will re-occure I'm going to need advise on the exact procedure and redo all arround the windows. Our canopy top is white, (base coat clear coat) and I hope repainting the top will not be a nightmare?
Seeking advise.
Ron
 
It is possible that the glass and cabin top expanded at different rates.

Do you recall how much of a gap you left around the edge of the window and the cabin top recess?

Phil
 
I am at this part of the project right now.

Mine have a gap anywhere from 1/16" to ~1/8". Slightly more than the plans call for. I was planning on filling mine with balloons, sanding smooth, laying 2-4 pieces of 3oz glass cloth over the top, then blending in with more balloons to smooth out the transition.

It makes me wonder if a 2-part pour foam may not be a better option to bridge the gap and then lay the glass over it. That would allow them to expand as needed but you still have support for the glass.

Those are my thoughts. But I agree, I saw several at OSH that had these cracks. I was planning on 2-4 layers of glass just to try and give it a bit more support.

I'm curious to see what others might have experienced.

Phil
 
2 to 4 layers is a lot more than I have. I was afraid of the lump 4 layers would make, but a high spot wouls look better than cracks.
Ron
 
I am just fitting the canopy now, also. I was planning on filling the gap with a chopped fibre mix and rubbing flat. Then covering with some lightweight cloth and resin and blending. I don't see how you can get a crack if you are bridging the gap with cloth. Am I missing something?
 
Filled the gap with balloons, bridged with cloth. The first very small cracks just showed up after 400 hours of flying.:confused:
 
Cracks

I would (do) fill the seam around the windows with Sikaflex, sand it smooth, sand the 1" edge glass with 120 or 180 grit, and use at least 2 layers of 6oz minimum, (I use 2 layers of 8.9oz) glass cloth, or 2 layers of 5oz Carbon Fiber. It makes a nice bevel around the window and you can fill any large steps with micro if they are big enough, or blend it a bit with a DA and use "Metal Glaze" filler to fair it in. I have never seen this crack between the window and cabin top. Just like the metal, the fiberglass, and acrylic expand at different rates. one layer of cloth, especially 3oz is not going to do it. Another way to do it is install the windows (except the windshield) with a perfect constant 1/8" gap around it, Sika it in, but not the edge itself, mask off the edge and paint the fuselage, then come back mask and fill that perfect gap with sika, run your finger around it to give a nice little concave bead, remove the tape and you have a perfect black fillet around the window. Very clean look, and no cracking, and easier to replace if ever needed? just a couple fool proof methods.
 
cracks

I used two layers of pretty heavy cloth around my windows and fillet them out over a wide area. When I took it to the painters, they decided to sand it down and paint it. My windows started to show the ridge of the gap within 50 hours. I showed the painters what happened and said I would split the cost to redo the canopy. They sanded down even more to level the ridge even though I told them to lay more glass or let me lay more glass. They thought it was the paint gassing??? The windows are showing it again and I have 85 hours on the plane. It's getting sanded, glassed and painted again on the 12th for free.
 
Cracks

I would call Grady at Glo custom paint. He can probably tell you how to avoid the cracks.

I used 1 layer of 2" glass tape overlapping the windows 1 inch. Then added micro balloon only on the tape and transition back to the canopy. I did not let any MB touch the window. Sand the transition smooth without sanding off the glass tape. When the aircraft was painted the paint did not extend past the edge of the glass tape, again did not touch the window. The final touch was a 3/4 inch band of black paint only on the window next to the glass tape. This in my opinion really set the paint off nicely and hides any of the glue used to install the glass.

My 2 cents but call Grady.
 
I'm not an RV-10 builder, but I'm curious about the nature of these cracks. Are they radial cracks or circumferential cracks?
 
Pat Stewart said:
I would call Grady at Glo custom paint. He can probably tell you how to avoid the cracks.

I used 1 layer of 2" glass tape overlapping the windows 1 inch. Then added micro balloon only on the tape and transition back to the canopy. I did not let any MB touch the window. Sand the transition smooth without sanding off the glass tape. When the aircraft was painted the paint did not extend past the edge of the glass tape, again did not touch the window. The final touch was a 3/4 inch band of black paint only on the window next to the glass tape. This in my opinion really set the paint off nicely and hides any of the glue used to install the glass.

My 2 cents but call Grady.
Click to expand...


Pat,

Please post a photo.

thanks,

bob
 
The cracks are same as usually found on other RV-10, but to a much lesser extent. They are like stess cracks in an area just above the seam 1/8" wide. The transparencies obviously expanded more than the canopy and pushed outward on the filler, glass and paint. I'll try to get some photo's for those not familiar with this problem.
Other than more layers of glass , any other options to stop this from occuring?
Ron
 
Ron,

My view for what's is worth is less fiberglass. One layer gives you the base to work with and the added protection of keeping that window in place. Dan or some one with more experience may want to jump in but the CTE problem I believe only gets worse with a heavier layup.

Bob, I will see if I can find a close up picture of the window edge and paint.

Pat
 
If building fill the gap with proseal, leave it slightly convex, prime and paint it. If flying route out a groove and do the same.

I filled with flox and covered with one layer of 3 oz glass on mine. I will probably get cracks. When we have a plane built out of alum, fg, acrylic and steel were bound to have some cracks show up. I knew I should have built that Velocity. I bet those guys have cracks too. Cracks really don't bother me as long as they are cosmetic. My house and both vehicles have cracks. Mine is for flying the family around the country not to win awards.
 
It's all good Wayne. Don't forget 30 milllion dollar Gulfstreams have the same cracking and you don't hear the owners whining in their single malts. Well, maybe a little.
 
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