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  #21  
Old 05-20-2007, 09:42 AM
Steve Sampson Steve Sampson is offline
 
Join Date: Aug 2005
Location: N. Yorkshire, England
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Default Overlapping Sikaflex

Mickey, thanks for that.

Reading through the various sources of Sikaflex info., most people talk about bonding in two stages. First to fix it, then cosmetics or to fill in gaps where clamps and spacers were located. This means that inevitably newer 295UV is going to meet up with not quite so new 295UV.

QUESTION: Anyone know how to maximise the bond between these two coats of the material?
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  #22  
Old 05-20-2007, 08:38 PM
phil9diesel phil9diesel is offline
 
Join Date: Mar 2007
Location: Upper ny
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Default glued canopy

How will the sicaflex compare when it's timwe to replace the canopy?
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  #23  
Old 05-21-2007, 06:08 AM
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Jim Ellis Jim Ellis is offline
 
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Location: Flower Mound, Texas
Posts: 122
Default Sanding Sikaflex

Sikaflex 295UV sands nicely with 120 grit open coat sandpaper. You can read about it here.
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  #24  
Old 05-21-2007, 09:27 PM
Rockyjs Rockyjs is offline
 
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Location: Gulf Breeze, FL
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Default

Jim,
Nice looking canopy! Did you make any adjustments on the cabin frame during construction to allow for the thickness of the Sikaflex? I really like the combination of gluing and screwing that you used, but my cabin frame is built to plans, and it seems that the width of the cabin frame would have to be made smaller on the order of twice the spacers (bead) width less. Or am I missing something? Thanks
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  #25  
Old 05-22-2007, 06:27 AM
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Jim Ellis Jim Ellis is offline
 
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Default Spacing Plexiglass

Hi Rocky,

My frame was also built to plans.

I taped rubber hose washers on canopy bow and under front bottom edge where plexi touches the cowl while trimming to final size. This created the 3/16" gap needed. Plexiglass canopy has plenty of excess material on the sides to allow for the repositioning that occurs.

The plexiglass is glued to the frame side rails but I made no great effort to maintain spacing on the sides. (Note the clamps.) Instead I ran an additional bead of Sikaflex along the bottom edge of the plexiglass along the side rails. And, of course, after everything had set up I added the "chicken" bolts along the sides per the plans.

Hope this helps.
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RV-7A, N23VC, Slider, Garmin G3X Touch Panel,
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Dual P-Mags, Airflow Performance FM200A,
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  #26  
Old 05-22-2007, 07:12 AM
Rockyjs Rockyjs is offline
 
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Location: Gulf Breeze, FL
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Default

Thanks Jim. Your method of attachment is well done and obviously looks great!
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  #27  
Old 05-22-2007, 07:49 PM
tonyjohnson tonyjohnson is offline
 
Join Date: Jan 2005
Location: Orlando, FL
Posts: 809
Default the sequence

Guys, there is something that I must be missing.

Mickey put small blobs in to adhere the canopy in place, then came back later to fill in the rest. Eric put in most of the sikaflex then came back the next day to do the cosmetic coat. I am assuming, which is dangerous, that the issue of doing the sikaflex process in two days revolves around the time limit of 30 min to 2 hours between the primer and the 295.

Is it not possible by priming and applying the sika 295 a section at a time?

I plan to use 3/8 inch spacers to hold the canopy off the frame while I apply the sikaflex. It seems possible to get the primer between the two surfaces easily with that distance of "standoff".

Once again, is there something that I am missing? I am ready to glue, but I want to make sure that I have a complete understanding of the options before I begin.

Tony
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  #28  
Old 05-22-2007, 08:56 PM
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Radomir Radomir is offline
 
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Location: Charlotte, NC
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Where does it say you have to apply it within 2 hours? I just looked at the instructions again and I see no reference to it. It does say to wait 30 minutes for primer to dry...
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  #29  
Old 05-22-2007, 09:13 PM
tonyjohnson tonyjohnson is offline
 
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Location: Orlando, FL
Posts: 809
Default 2 hour limit

Radomir,

I got that from the very detailed writeup done by Eric Wolf which can be found on Mickey Coggins website.


"Other builders have applied the glue in a few blobs first, then coming back the next day and filling/smoothing. This works OK, but the instructions for Sikaflexspecifically say that the glue should be applied within 2 hours of applying the primer."

I just took a quick look at the sikaflex 295 and primer containers in my shop. I did not see a reference to the 2 hour limit on the product. The instructions on the product did say that there was a more detailed data sheet available from sikaflex.

Perhaps Mickey, Eric or Jim can chime in here on the topic.
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  #30  
Old 05-22-2007, 09:36 PM
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Radomir Radomir is offline
 
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Default

Ah, I think I found it.. I believe this is what they're referring to and explains the reasons for the "2 hour window:" (may or may not apply to us)

"Waiting too long, however, to apply the adhesive risks having the bonding surface contaminated with dust or debris. Therefore, it is recommended to apply Sikaflex ? within 2-3 hours of the primer application."

This is under generic Sikaflex suggestions for best bond. There's no such reference specifically for 295 (and maybe more importantly, no *requirement*).
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