ArVeeNiner

ArVeeNiner

Well Known Member
I would like to bond my slider frame to my Plexiglass this weekend. My frame width is adjusted pretty well on the fuselage right now. I have measured that when the Plexi is clamped to the frame, it spreads it 5/16". Now, I could bend the frame narrower by this amount before I bond but I'm afraid that this would lead to another tweek here and there and pretty soon I'd be regretting messing with it.

I know from other builder sites that the Sikaflex can more or less hold the frame in the position that you put it in. Basically, a strap is used to bring the frame in a bit to compenstate for the spread. Then, it is glued and the Sikaflex tends to hold it in that position by some amount.

The question I have is how well does the Sika hold that shape? If I pull the frame in by 5/16", will the Sika hold it at 5/16" or will there be some spring back from there? I tend to think there will be some spring back so that I should overshoot a bit but by how much? Too bad there is no opportunity to practice this.

Thanks
 
I'll be where you are next week. I measured more like a 3/4" spread when I clamped on my canopy. After reading a few builder sites, I'm going to overcompensate and hold the front in 1" and the rear in 3/4" while the glue sets. After the Sika cures, if it doesn't fit perfectly, I will bend it as needed!

PS - wherre did you buy your Sika, what products did you get, and did it come with nozzles? I think I need 2 different kinds of primer, the 295UV adhesive, and the cleaner. I was thinking of throwing in the "Aktivator" too for fun!
 
I've been in contact with a couple of people that have been through this process. Both said that you have to over compesate for the Plexi spring. One guy, Bret Smith as a matter of fact, told me to double the spring back so that would be 5/8" to compensate for the 5/16" that the Plexi is introducing. He has a good site that I've been referencing for a few weeks now.

I bought mine from merrittsupply.com

206GP-18 Sika Primer 206 G&P (206GP-18 - 250 ml. Bottle) Qty 1 $41.82
209-18 Sika Primer 209 Polyurethane-Based Black Primer (209-18 - 250 ml. Bottle) Qty 1 $48.09
226-18 Sika Cleaner 226 (226-18 - 250 ml. Bottle) Qty 1 $11.27
295120 Sikaflex 295 UV Resistant Marine Adhesive and Sealant (295120 Black 10 oz. Tube) Qty 3 $34.53 ($11.51 each)

I decided to buy the 206 G&P Primer for the rear skirt although I've since read that Sika has suggested that the 209 Primer would be OK.

Standard nozzles came with my Sika.
 
Last edited:
I used 3/4" pull

and it seemed to work well for the spring back. I bought my Sika from Jamestown Distributors and nozzles came with the order. YMMV
 
Correction

I came home and double checked everything. Yes, they do come with nozzles. They didn't come with the V nozzles that I've seen referred to on the Sika site so they are sending them for free. It turns out though that for our application I don't think we need the V nozzles. I think the normal ones are what everybody is using.
 
Last edited:
I had mine bent so that it was the correct width while the plexi was clamped to the frame. During glue up I made a couple of wood spacers to keep the the frame the exact width I wanted so it wouldn't set up in a undesired position. Turned out very well, rollers are centered in the tracks on each side.
 
How To compensate for the canopy spread using Sikaflex?

I Sikaflexed my RV-8 canopy onto the slider frame with the slider frame mounted on the fuselage. I first drilled the canopy to the slider frame in a number of spots along the bottom rail where the fiberglass trim was going to cover the holes, to get a good alignment. Next I drilled the fiberglass trim and clecoed both the slider frame, canopy, and trim together, so that both the trim and the canopy were aligned with the slider frame where I wanted them.

I then removed the fiberglass trim and put tape on the top and bottom of the canopy along the slider frame rails to mark the line to prime the inside of the canopy where it was going to fit on the frame. I then took the canopy off the slider frame, turned it upside down and primed inside the tape lines. I then primed the canopy rail and before putting the canopy back on the frame, ran a bead of Sikaflex on the entire slider frame and using a helper placed the canopy back on the slider frame and clecoed the canopy back on the frame.

Naturally the Sikaflex doesn't stick to the clecos because they aren't primed and where the Sikaflex pushed through the cleco holes and got on the outside of the canopy, after it dried, it pealed off like rubber since the outside of the canopy also did not have primer on it.

After the Canopy had set up on the slider frame I removed the cleco's, cleaned out the holes and then primed the outside of the canopy and the inside of the fiberglass trim where I wanted the trim attached and applied Sikaflex where I wanted it, clecoed the fiberglass trim back on the canopy and once it set up removed the cleco's, cleaned out the holes and fiberglassed the holes on the fiberglass trim.

Best regards,
 
Plexi Spread

Okay, I don't get it. Should I bend the frame in 1/2" in the front and 3/8" in the back after all looks good measurement-wise, OR should I just pull it in with straps prior to Sika? Different measurement opinions are welcome, but I really need to know about the 'bend' vs 'pull'. Thanks much!
 
LOTS of differing opinions here.....

....but I just went through it and I will tell you my experience.
After having the frame bent and fitting perfectly, I clamped on the ready-to-be-glued plexi canopy and measured the spread. In my case it spread 3/4" at the roll bar end, and heeding the advice of some others, I pulled it in 1 1/2" with ratchet straps prior to bonding. The bonding went very well, I gave it a week to cure, removed the straps, and was surprised to see the frame spring back to the point that it was still 3/8" too wide. Yikes. I'd read that the frames are still bendable after the sika has cured, and just this afternoon I decided to find out how true that is.
It was more than a little scary using all my body weight, and strength (such as it is) to attempt to compress the frame that 3/8". As much pressure as I was putting on the frame, I was sure the glass would crack, but (as advertised) the sika is so flexible it did indeed allow me to achieve the necessary compression of the frame, and it now rolls perfectly in the tracks. Funny to see your post, because prior to this afternoon I was thinking if I had to do it over again I might pre-bend the frame so that when the plexi is clamped on prior to gluing the spread would result in the ultimate size. But since I just experienced an "all's well that ends well" day I am very happy with the approach I took. I guess the bottom line is, unlike riveted canopies, the sikaflex approach is very forgiving.
Now it would be a miracle if you're not more confused than ever.

Geoffrey Patterson
RV9A
Camarillo, CA
.
 
You must log in or register to reply here.