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Any Sikaflex bonding failures?

Blain

Well Known Member
There was quite a debate going on here 8 or 9 years ago when builders began bonding canopys. One of the arguments was "No history". Well, now we have history.
Has anyone experienced a failure of any type relating to a Sikaflexed canopy?

I bonded my Todds on the -8 project and am convinced its the best thing since sliced bread. But my project is still in the shop. How about you guys who have time on your ship, any squawks to report?
 
I finished mine in 2007. No regrets. In fact, I don't recall ever reading a post here where someone had a silkaflex failure.
 
Mine's been flying for over 5 years...no problems at all, and haven't heard of anyone else having a problem, either.
 
Mine has been flying for 6 years, still as solid as first flight. I agree it is the only way to go - no holes, no cracks!
 
8 years and 1200+ hours. Mine still looks and feels good. -10 to + 114 deg F..... but not in the same day......
 
Does Van ever go back and endorse improvements? Or does he release a design and move on to the next?

I don't want to re-invent the wheel. I just want the best wheel available.
 
Blain,

A while back, I did a little experiment with some expired Sika products that had been sitting on my shelf for a very long time. You may not have seen it, but it's posted right here:

Expired Sika Products - an Experiment

I still have this test piece in my shop, and I'm going to hang onto it. I've showed it a number of people and it looks just like it did about 8 months ago when I did this. Granted, that's not all that long ago, but again, this was with Sika products that had been expired for a long time! Using all my strength, I cannot pull it apart. We're talking about 1 square inch, roughly, and about 1/16" thick. Nobody else has been able to pull it apart either.

Anyway, I thought you might enjoy taking a look at it. :)
 
When I was doing my canopy I did some test pieces and I found out that the proper prep and priming is very important.

Without prep and priming you can pull it apart with ease.

With proper prep and priming the aluminum will tear before it will come loose.
 
So why wont Van endorse a improvement? Lawyer under every rock? (wing) This seems like one of those obvious mods that they should at least acknowlage.

Since I've already gone there and bonded mine I guess I should get over it but a statement like "Bonding is an option to consider" or "improvements have been made in canopy attachement options" from our leader would legitimize the process. Not to mention listing the correct adhesive, primer, working time. etc.
 
So why wont Van endorse a improvement? Lawyer under every rock? (wing) This seems like one of those obvious mods that they should at least acknowlage.

Well, it *is* more expensive and it *is* slightly heavier than riveting the assembly together. Both of those things seem to be an anathema to Van's design philosophy, although that does seem to be changing as of late with the -10, -14, etc.
 
I also think that Vans would be hesitant to endorse a product whose own manufacturer refuses to endorse it for the application. Would put all the liability on them. That being said, I am certainly leaning towards bonding, myself...

Chris
 
Well, it *is* more expensive and it *is* slightly heavier than riveting the assembly together. Both of those things seem to be an anathema to Van's design philosophy, although that does seem to be changing as of late with the -10, -14, etc.

I also think that Vans would be hesitant to endorse a product whose own manufacturer refuses to endorse it for the application. Would put all the liability on them.

Both strong reasons it hasn't been embraced/endorsed.

A couple more...

- It is rare that more than one process will be recommended because of the literally hundreds of tech calls it produces. People call wanting to know which one is the best choice...:rolleyes: ,as demonstrated by some of this discussion... people want to know what is best. No one can make that decision for a builder. If they use the bonding method under someone else's recommendation that it is the best, and then they later have the canopy come unbonded because of installation errors, was it the best choice for them? Probably not. If you choose to deviate, do the research and then make your own choice.

The process has never been considered as a recommended replacement for what is done currently, because of its high level of sensitivity to following the prep and bonding process exactly (as has been already mentioned). I admit the current process is also not perfect (I don't think the Sika method is either) but it is a method that is easily verifiable. A screw or rivet can be visually verified that it is either properly installed, or it isn't.
 
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I used 3M 5200 at the advice from Todd at Todds' Canopies. I have not flown it yet, but I do have a small test piece at the shop that nobody can pull apart with pliers and a vise. I have no worries at all.
 
The spirit of homebuilding

I'm kind of wondering what's happening with the spirit of homebuilding? Do we really WANT everything to be mandated by the kit manufacturer? I know a lot of folks do, because it makes things easier. aka RV-12.

I however, like the idea that I can make some decisions through shared information amongst the tribe. The ability to personalize the aircraft through engine, avionics, interiors makes this all more interesting to me.

What fun would it be to go to a fly in where every RV was just like every other. Kind of like walking through a new car lot where they're all the same. This is why you don't get throngs of people walking through the north 40 at Oshkosh. Every C172 is just like the other.

The choices keep this all interesting, and as others have pointed out, the kit manufacturer can't be expected to provide tech support for every possible builder variation.

Makes sense to me.

(edit: sorry about my contribution to thread drift...)
 
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I don't think he is so much looking for a blessing from Van, rather a validation that his canopy won't come off at an inopportune time. A lot of people have bonded their canopies on without Vans' blessings and without problems, so the spirit of "experimental" is still alive.
 
I don't think he is so much looking for a blessing from Van, rather a validation that his canopy won't come off at an inopportune time. A lot of people have bonded their canopies on without Vans' blessings and without problems, so the spirit of "experimental" is still alive.

You said it; A "Validation". Thats all I was looking for. However prior posters bring up valid reasons why not. As close as I'll get to validation will be those who confirm several years and hundreds of hours with no problems.

Interesting though, Van did express his thoughts on various diversions in RVator. Everything from auto engines to fairing designs. Seems to have become more conservative in his public comments now.

I have a copy of 27 years of RVator and considered it the bible. But even much of that has become obsolete. I guess VAF is the new "Bible"?
 
As far as I know I have the oldest canopy that was fully bonded with Sika 295. Chalkie bonded his before mine but had some screws and rivets.
I bonded the canopy in 2002 and first flight was on the 21Jan 2003. My Rv6A slider now has 700hrs with no problems at all.

The boding procedure has to be followed exactly to ensure a good bond.
I.e. Surface preparation, cleaning with correct cleaner, priming with correct primer, applying the Sika within the 24hr period, maintaining a minimum thickness of 1/8" and protecting the bond from UV by painting the acrylic above the bond with appropriate reflective paint.

We also examined the canopy bond of another RV6 that had an unfortunate meeting with a power line and found that the Sika did not fail at any point but acrylic had failed next to the bond.
 
As far as I know I have the oldest canopy that was fully bonded with Sika 295. Chalkie bonded his before mine but had some screws and rivets.
I bonded the canopy in 2002 and first flight was on the 21Jan 2003. My Rv6A slider now has 700hrs with no problems at all.

The boding procedure has to be followed exactly to ensure a good bond.
I.e. Surface preparation, cleaning with correct cleaner, priming with correct primer, applying the Sika within the 24hr period, maintaining a minimum thickness of 1/8" and protecting the bond from UV by painting the acrylic above the bond with appropriate reflective paint.

We also examined the canopy bond of another RV6 that had an unfortunate meeting with a power line and found that the Sika did not fail at any point but acrylic had failed next to the bond.

I made the call to Sika tech support and after the "We don't endorse this application" he advised the same 295, cleaner, primer, etc. I assembled per those instructions. I'm comfortable with the final product.
 
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