[pvalovich]

I just finished gluing my -8A canopy. Like the old Navy jingle - not just a job, but an adventure! Here are some things I learned, relearned - and some where I wished I had paid more attention to the postings of earlier builders:

1. Fitting the canopy to the frame: use the "real" spacers to adjust the fit. A little bit of spacer makes a big difference in final fit.

2. Spacers: I used the 3/8 squares of cut 3/16 adhesive backed rubber from McMasters. BIG MISTAKE. The adhesive didn't work well, causing the spacers to shift and ultimately protrude beyond the Sik bead - or shift and screw up the clearance between the canaopy and frame. Use hose segments.

3. Use hose segments for spacing, apply enough "dabs" to hold the canopy in place - eventually without clamps, think about it for at least 24 hours, then go back and remove the clamps and purty it up with continuous beads.

4. Aesthetics - some folks may be able to make nice looking filets - I couldn't without an awful lot of effort. Supposedly, soapy water on the finger helps.

5. Size matters: I ended up with 2 - 3 aesthetic coats, causing the Sika seam to be bigger than I wanted. Start small.

6. Black Death II: Cover everything - inside and out - you don't want Sikaflexed. The 295 eventually comes off unprimed surfaces but not as easily as you might gather from some postings. Be careful of the primer.

7. Sikaflex Cleaner - offered on the Jamestown website, was worthless. Alcohol, Acetone, Coleman Fhel work better.

8. Timing: Clean, prime and install the first dabs within the published 2 hour limit. After that you can do sections at a time.

9. Edges: Popsicle sticks edge on repeatedly moved back and forth with a lot of pressure will slowly remove ragged non-primed edges.

10. Timing II: It took a lot longer than I thought it would.

11. Canopy Support: I used a cut out large cardboard box to set the inverted canopy into to apply Sik from the bottom. Used 2 Home Depot plastic horses connected by 1X2's with adjustment blocks nailed on for the upright canopy. Make sure you tie it down to prevent fore and aft movement.

FWIW.
Paul Valovich
-8A N192NM Reserved - Again!
Ridgecrest, CA

 

[Bill Phillips]

More Sika Tips

I am working on fitting the shirts onto my RV-8a canopy that I "glued" with Sika. I really like the process over rivetting a canopy. Tip # 1. Wait to fill the spaces where you remove the hose spacers and clamps until you have drilled on the skirts because once you apply the primer and Sika you cannot see the frame from the outside. Even though I don't plan to rivet the top lip of the skirt to the frame I do need to clamp it to the canopy for the Sika bead at the top. If you leave the hose/clamps gaps you can see through to drill the holes for the clecos. Otherwise you are just guessing where to drill. Tip # 2. The primer is tough as nails when it dries and will drip and stick and get damed hard and difficult to remove. Mask off anything and everything the primer can get on.

 

[deene]

I also just finished installing my RV8 fastback canopy with Sikaflex. Some comments:

1. Cutting and fitting canopy took about two days, slow and easy. Final fit is best done after the big cut as small adjustments were much easier.

2. I used superglue to hold the small square spacers (cut from water heater hose) and once glued, they only came off by cutting. Initial experiment with contact cement didn't work well...

3. I have problems getting my clamps to hold without distorting the edge of the plex. Careful setting worked most of the time. Many spring clamps are required (~20).

4. Cleanup is challenging...as mentioned in an earlier post, mask everything, and work carefully. Small smudges and pieces of the adhesive come off by rubbing.

5. I haven't finished prepping the skirts (custom as the standard ones don't fit a fastback), but plan on gluing the top of the skirts to the canopy with Sikaflex also.

6. I have just about finished two tubes of adhesive and will probably order one more to finish (will have plenty left over). Careful application could get by with 2 tubes.

Sikaflex is tough stuff once set. I did some test samples to keep...I don't think the canopy is ever coming off with out destroying it!

I hope to post some pixs later.

 

[scsmith]

tip for top edge of skirt

HI,
When gluing the skirt to the canopy with Sikaflex, here are some thoughts.

1) drilling some holes for clecos into the frame is a good idea if you think of it before doing the full bead on the canopy, as mentioned above. I didn't, so I made up 15 custom "C" clamps out of wood that can reach around the frame and clamp the edge.

2) you don't need a 1/8 gap, structural type joint where the skirt joins to to the canopy. You are just trying to make a weather-tight seal. And you would like a nice close, even fit. BUT you do not want the joint to go to zero thickness anywhere and squeeze all the Sikaflex out. So, here's what I did. I bought a cheap spool of heavy fishing line, I think it was 50 lb test, something like 0.030 in diameter. I tack-glued the fishing line to the skirt along the surface that would mate to the canopy, about a 1/4 inch down from the edge, using a drop of superglue about every 4 inches. Then, I put on a bead of Sikaflex, put the skirt into position, clecoed to the frame, and used my wood clamps along the edge to close any big gaps.

The nylon line forces a nice even 0.030 gap for the Sikaflex, preventing it from squeezing it to zero gap anywhere. There is an inch of bond width there, so leaving the line in there forever is no big deal.

It turned out great.

 

[Bill Phillips]

Sika Skirts

Steve, when you fit your skirts did you have to deal with the top lip puckered away from the canopy sides? To get that to flush up can you "adjust" it with a heat gun? Off the canopy of course.