What is your favorite method for fiberglassing wing center sections? I have used regular resin and finishing resin but this is my favorite to ensure a smooth, bubble free application.

After sanding the center section, mark off the location of the fiberglass tape.
Mask off the rest of the wing with tape and newspaper
From 12 inches away spray a light coat of 3M Super 77 adhesive on the tape area and let dry for about 15 minutes.
Apply the tape and position and press smooth. Don't wrap the tape around the wing, do it in two pieces.
Coat the tape with thin CA glue. It will spread evenly over the tape as you apply it. No need to spread it out.
The fiberglass tape color will change from white to balsa colored so you can see which areas still need CA.
Add some thin CA to the balsa area next to the tape to aid in sanding.

This takes a lot of thin CA and generates a lot of fumes so do it in a well ventilated area or best do it outside.

Anything that securely bonds the cloth or tape will do. I've used resin, epoxy, Titebond, CA, and Ambroid.

Titebond stinks the least, Ambroid sands the best.

I cut Carbon Graphite fabric on the bias so the weave runs + - 45 degrees. Laminate the fabric with an epoxy laminating resin, peel ply, bleeder fabric, and vacuum bag. The lightest, strongest way to reinforce a center section joint. Not that much more work for a much better result.

Hi!
The Ca glue metod is no good! Its messy and the surface gets to hard.
A much better metod is to just lay out several layers 25g glass Weave (or 105g satin weave) on the center section, shaped to a diamond form for strongest and stiffest structure, and then pour on some 24 or 30 hour epoxy, spread out with SIG plastic spreader or soft brush.
No contact spray is needed or should be used. When the epoxy has dried after one or two days it's hard but easily sanded with 240 paper. Oracover plastic film is then easily fastened to the glass surface.

o.k but what do you do with arfs? I just epoxy the wings together as instructed and have never had one separate. Even in a mid air collision they have stayed together.

ARFs are designed differently and the center ribs are often plywood, many balsa kits the fiberglass is the main thing holding the two wing halves together.