Glassing the wing joint -- question
 

I'm at the point in my wing construction where I'm ready to lay a piece of glass over the joint. I've got a length of GP 2" "medium" tape. One side has a thicker edge than the other (to stop fraying). Should I attempt to cut off this thick edge before putting it on, or will it smooth out in the end?

Thanks

RE: Glassing the wing joint -- question
 

It wont smooth out. You can cut it off if you want, if you do make sure youve got a good pair of scissors.

RE: Glassing the wing joint -- question
 

If the glass tape lies completely inside the fuselage, I would not bother to trim it down. If I had the option of going to the hobby shop and picking up a yard of light to medium cloth, I would cut a piece that extended the full width of the fuselage plus about 3/8 of an inch or so on each side of the fuselage to permit a more solid contact between the wing and fuselage.

It also prevents a lot of the denting that takes place on the wing between saddle and the wing when you tighten down the screws or use a lot of rubber bands for wing retention.

RE: Glassing the wing joint -- question
 

FWIW, craft shops sell a little rig consisting of a cutting mat and a roller cutter for cutting cloth. Olfa is the brand, I think. Everyone needs a cutting mat, anyway. Spray the FG cloth with a little hair spray to hold the threads, and cut it with the roller cutter and a straightedge. Works great.

RE: Glassing the wing joint -- question
 

Thanks for the quick replies. I like the idea of glassing the part that will meet the fuse, but this will require as much as 5 3/8" glass in one section. Does that sound reasonable? Also, should I stick to the 2" on the underside of the wing since its not going to touch the fuse? The kit only came with a 3/4" strip, but i don't think i could sleep with something that small.

Thanks

RE: Glassing the wing joint -- question
 

Dwango,
Just an FYI. On my very first ARF an LT-40 I couldn't figure out how to keep the two wing halves flush while the epoxy was drying. So I clamped the wing at the aileron cutout and taped the rest. I then stood the wing vertically!! I checked on it for a half hour and went to eat. Long story - when I came back the next day the wing had a 1/4" twist. My fellow club members thought it was hilarious. Later they told me to prop one end of the wing end up flat on the table. Ah well. So I cut the wing in half. Glued each half together with one end propped up on the table. Voila a straight wing. All the hobby shop had was 1" wide fiberglass tape so I pealed back the covering and epoxied it completely around the wing.

That was 4 years ago. The wing has hit a pine tree hard enough to crush the leading edge back 2". Repaired it then flew it into the tops of some poplar trees learning depth perception. It has survived full power dives, full power snaps, cartwheels that required replacing a wing tip. But the center joint has had no problems - ZERO - no dihedral brace and only 1" wide fiberglass tape with epoxy holding the wing together!

I fiberglass all my wings now. I usually use 3-4" wide tape but was amazed at what 1" tape can do if properly applied.
John

RE: Glassing the wing joint -- question
 

Dwango,

I glass ALL my center sections so that the glass extends past the fuselage sides. The width, 3", 6" 12" or whatever, depending on the width of the fuselage, doesn't bother me. I know that I will ALWAYS have a center section that will stand up to the stresses I will put it through. I also don't use epoxy resin for glass work. I use polyester resin because it soaks into the wood for a better bond with much higher strength, rather that sitting on top of the wood.

RE: Glassing the wing joint -- question
 

When cutting fiberglass cloth... it helps to prepare the cloth by lightly spraying wth 3M formula 77 adhesive. This binds the weave and makes the cloth easier to handle. (let the adhesive dry for an hour after spraying and it is kind of like post-it note adheive. Tacky, but eay to peel)

RE: Glassing the wing joint -- question
 

I use very light FG to cover the wing joint and when cutting it I had trouble with it fraying. Solution: I lay the glass on a sheet of paper (Dry) and cut them both together with a pair of sissors. Works great!

RE: Glassing the wing joint -- question
 

I took kdheath's advice and bought one of those OLFA rotary cutters at the craft store. Came with one of those "self healing" rubber mats. It's a dream come true for cutting fiberglass, and I'd at $25 it wasn't too expensive, either.

RE: Glassing the wing joint -- question
 

I've even used multiple layers of 3/4 oz cloth. Start with a 1" wide strip in the middle and add layers (while still wet). Each layer is cut a little wider than the next until you get the number of layers and width you want. Cut all of them ahead of time and lay out in order. This way you have 5 or 6 layers thick at the joint for strength, and it tapers to very thin single layer at the edge. I also use masking tape chordwise spaced about an inch further out on the wing than the widest fiberglass pieice and paint the epoxy all the way out to the line. Remove the tape while the eopxy is still wet and the edge will lay down to a nice smooth transition. With a little light sanding, and covering, you can't even tell it is there!

Richard
Tomball, TX