More RV-8A Canopy Woes

[pvalovich]

Even though my -8A Sika-attached canopy doesn't have a single rivet, I've developed two cracks just forward of the aft cross brace, one on each side. The first 3" crack occurred nearly three years ago and was stabilized with a 1/8 stop-drilled hole - until yesterday. I discovered that the crack now goes through the stop-drilled hole for another 4 inches.

That indistinct roar you heard yesterday was me going through my expletive vocabulary and discovering once again that cussing at it doesn't fix things.

I've used the forum search engine to assemble numerous posts regarding crack repair that have generated questions:

1. Weld-on seems to be a popular "fix" but there are references to Weld-on 4, 10 and 16. What's the difference?
2. In using Weld-on, do I need syringes or are the applicators offered with the product good enough?
3. Acrifix 192 is also recommended. Is it better?

Appreciate any feedback from the forum expertise. The only downside of the -8A experience (650+ hrs in 41/2 years) has been worry about the canopy. I obviously introduced stress points during the Sika process, but don't recall what I could have done wrong.

[Ironflight]

That crack location seems to be very common - and coincident to the weld where the tubing changes diameter. I am of the opinion that we put a lot of strss on the canopy right there, becasue of that weld. Doesn't help you with a fix, but next time around, I'd file that transition smooth where it touches the canopy....