Crack in canopy

[BABALU]

Ok I bought a flying RV 9A .It's a decent build but has some issues that really bug me ,The one I don't how to fix is a crack in the top dead center of the slider canopy.It runs wing to wing about 7 inches long .Is there any hope of repair or will I have to replace the canopy plexiglass. It has been drilled at each end of the crack to stop from spreading and it seems secure when flying .

[Bob Redman]

G'day ClaytonRV6,

I posted several months back - search on 'Cracked Canopy'. There are other threads.

Quote:

I repaired the crack using Weldon #3, and the stop drill holes with Weldon #16, as per the first post. The #3 did not wick very far in the crack, so I applied it along the length of the crack using a fine point syringe while trying to hold the plexi even along the crack while the #3 cured. Then I used a larger tip syringe to fill the stop drill hole with #16. The repair looked adequate.

Following advice on an Australian forum (SAAA - Sports Aircraft Assoc of Australia), I re-did the repair using Acrifix 192 (Acrifix 1R 0192, go www.evonik.com/acrifix-1r0192). The repair was a definite improvement helped by: the lessons learnt using WeldOn; and easier application using the Acrifix tube (think toothpaste) vs the medical syringes used for the WeldOn (pint tins).

I dressed the repair on the outside of the canopy using a MicroMesh repair kit from Aircraft Spruce. The crack is too close to the left rear canopy bow, so I will dress the inside of the repair next time I remove the canopy - probably I would cause more damage if I dressed the crack while the canopy was on the aircraft.

The MicroMesh systems worked well.

Although the crack is obvious to me on the ground, I do not notice it in flight, and can not see it with a passenger in the left seat.

Finish quote.

A few flights later all going well up to VNE and 0 to +4G.

Good luck with the repair.

Regards,

[Skid]

I repaired a crack in my canopy a while back. I have had no issues with it to date. While it is visible, it seems to be more visible from the inside of the airplane than out. I had to point it out to some guys at Oshkosh earlier this week.

The link below is to my write up.

http://www.vansairforce.com/communit...ad.php?t=68505

[BABALU]

Thanks Bob and Skid ,for the input and the very helpful info. Based on what you've shared I feel a can give it a go and at least keep it safe for flight.

Very much appreciated,
Andy

[mr.sun]

I am considering stop drilling a small canopy crack before going flying today. The 15 year old RV6 with slider canopy lives in an unsheathed hangar that will be about 35 degrees F. Should I put a space heater inside the cockpit for a while or use a heat gun sparingly? Or just use a tiny bit and drill it cold? Slow speed drill or fast Dremel tool? Plan is to chamfer both sides with a larger bit by hand. Thoughts, gentlemen?

[Kyle Boatright]

Originally Posted by mr.sun

I am considering stop drilling a small canopy crack before going flying today. The 15 year old RV6 with slider canopy lives in an unsheathed hangar that will be about 35 degrees F. Should I put a space heater inside the cockpit for a while or use a heat gun sparingly? Or just use a tiny bit and drill it cold? Slow speed drill or fast Dremel tool? Plan is to chamfer both sides with a larger bit by hand. Thoughts, gentlemen?

My opinion? Space heater + small drill. I might put the space heater inside for 30 minutes with a packing blanket over the entire bubble. Once it is warm, pull the blanket and drill immediately.

[Randy]

Heat it up with heater or wait for a warmer day.

Check out the video on EAA regarding repair of cracks in plexiglass. They recommend stop drilling, of course, with a plexiglass drill. On mine, I started out with a 3/32" stop drilled hole but the crack had re started at the top of the hole. I carefully filed it out larger with a needle file rather than risk further cracking via the drilling method.

Then, using Weld On 40 two part glue, I glued in a 3/16" piece of plexiglass rod into the hole. The rod can then be cut off after curing and sanded and polished out to a pretty good optically clear repair.

In the video they claim to have actually replaced sections of windscreen by gluing a new piece into position..

Here is a link to the video.
http://www.eaavideo.org/video.aspx?v=1967301183001

[RV6airplanePilot]

was recommended to me by plexi shop, rather than drill. Worked great for me and no risk of new or extended cracks.

[rightrudder]

Originally Posted by RV6airplanePilot

was recommended to me by plexi shop, rather than drill. Worked great for me and no risk of new or extended cracks.

And it cauterizes the wound too!

[rvbuilder2002]

Originally Posted by RV6airplanePilot

was recommended to me by plexi shop, rather than drill. Worked great for me and no risk of new or extended cracks.

And other people that work with Acrylic professionally say to never heat locally to treat an edge or a hole... only over a large area for bending along a line in the middle of a sheet or forming a bubble (like our canopies)... that is can cause additional stress risers that can cause other problems.

I don't know which is true, but I tend to avoid localized heating....