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Attaching Canopy with Adhesive??

John Adams

I'm New Here
Did you use adhesive to attach your canopy plexi? What brand/spec adhesive did you use? Are you pleased with the results? Did you not use any rivets? It seems to me the adhesion is no better than the powder paint on the canopy frame being glued to. Why not scrape off the powder coat to adhere plexi to bare metal? How do adhesives accommodate the extensive (4X) thermal expansion rate of plexi over aluminum/steel? I am thinking of a mix of rivets (piece of mind) and adhesive. And, perhaps only using rivets on one end of each plexi panel (slider) to accommodate expansion. Sure wouldn't want to have a blow off. Your wisdom please.
 
SikaFlex 295UV

John,

I bonded my canopy to the slider frame using SikaFlex 295UV and so far (18 hours) it is working well. There have been a few threads on this subject, search for Sikaflex.

I scuffed the powder coated canopy frame before bonding.

The Sika product needs to be a minumum thickness derived from a table in the data sheet to account for the CTE difference. The adhesive is pliable and stretches to accomodate CTE.

I have a few pictures at:

http://websites.expercraft.com/skytrash/


Jim Bray
 
Adhesive works

It is holding no problem.
I have about 60 hours, most of it @200kts. Canopy, skirts, and windscreen all glued no rivets.
There is no chance of it coming off OR ever cracking via natural causes.
Kahuna
S8
 
I have about fifty hours on my RV-7A built using the RV sika instructions from sport aviation. I'm very happy with how it turned out.
 
Which Sport Aviation

Which issue of Sport Aviation was the article published in? I must have skipped reading it.

Thanks, Pete
 
penguin said:
Which issue of Sport Aviation was the article published in? I must have skipped reading it.

Alas - I've misplaced it now. It was about two years ago - an article by Chalkie <forgot last name> in South Africa. A very good write-up on how to use Sika to bond on a RV canopy.
 
Clecos??

I would like to do it without any holes too. How did you stabilize the canopy while cutting front from rear? No holes = no clecos.
 
Sport Aviation Jan 2004

Alas - I've misplaced it now. It was about two years ago - an article by Chalkie <forgot last name> in South Africa. A very good write-up on how to use Sika to bond on a RV canopy.

Sport Aviation Jan 2004 pg 97
 
I glued and riveted. Not flying yet but my reasons were several. Most of the cracks that are reported here start from the holes for the rivets. I riveted mine together first then glued with Sikaflex 295. Doing it this way you cannot have the desired thickness between the canopy and frame but more of a fillet like a weld. I think the Sika will keep the canopy from being able to move and put pressure on the rivet holes. By riveting first I was able to put the canopy in the proper shape to fit good before gluing. With only Sika I am not sure how you would get as good of a fit. I am sure that some folks on here are better at Sika work than I am. One thing that I will mention is that it is VERY important to do all of the steps that the Sika says to do. I did a few test pieces and without all the steps you can pull it apart with your hands. I hope this makes since. And yes, if the powder coat is still on the frame the bond can not be any stronger than the powder coat IMHO. If you want to use the powder coat for your bonding base go for it.
 
Silka

This brings up a concern. I want to Silka the canopy.
I think Vans sells the weldments bare if you want.
Would it be advisable to get everything fit then mask off the areas where Silka will adhere so the frame stays bare or is it better to glue to powder coat?
I really want to powder coat the frame something other than Vans white.
 
My frame was powder coated and the I painted it black. I taped off the bonding area and sanded the devil out of it. Prepped it right. I do not have any doubt this stuff will never let go! I drilled some #40 holes thru the canopy and canopy frame and roll bar and used clecos with pieces of small tygon fuel tubing for spacers. I varied the thickness of the fuel tubing spacers to get the required gap and a perfect fit. I then applied the Sika Flex in between the clecos. Next day I removed the clecos and finished the fillets. It worked great and I wouldnt change a thing.
 
Sikaflex at 150 hours

I did the sikaflex method and it's definitely not coming off. Actually, I did it on 2 planes at the same time. I did it on my RV8A and a Zodiac 601 we were selling. I flew the Zodiac to Alabama to the new owner and within a week the canopy was destroyed while being opened in windy conditions (yanked out of his hand). The canopy was cracked in several places and the frame was bent, but the sikaflex held tight. In fact, he couldn't get the sikaflex off the frame and had to buy a new one.
 
We used Sika to attach our canopy 3 years ago and have been flying for 6 months and 100 problem free hours. I would highly recommend it over using bolts!
 
Sika bonded canopy

I've got 7.5 years and over 400 hours on mine. No holes in my plexi. You could pick up the plane by my canopy - it is that solid a joint. I would not hesitate to bond to the powder coat - just scuff it up and use the cleaner & primer. The powder coat will come off the metal before the Sika comes off the powder coat :eek:
 
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