Balsa NC and Screw Eye Installation

[rbeckey]

When I install a screw eye into balsa, I usually screw it in, unscrew it, put drop of thick CA in the hole, and screw it back in.
I then put a drop or two of thick CA on the eye were it touches the cone base.
What other methods have you found effective?

 

[jflis]

That's what I do as well, but I use yellow or white glue instead.


There are many who drill out the base of the cone and insert a short length of wood dowel to give the screw eye something to screw *into*. I've done this on some larger models, but not too often (mainly cuz i'm lazy... )

Another idea that I've been playing with is to use a tooth pick to poke 2 small holes in the base of the nose cone then take a 2-3" length of 35# kevlar with a knot in each end. I poke each knot deep into the holes and fill with glue making a small loop to attach the shock cord and recovery device.

 

[astronboy]

I do the screw-in, screw-out method with yellow glue as well.

With blow molded cones, I drill two holes in the base to attach my shock chord so that only my snap-swivel attaches to the plastic loop. I do this to avoid clearence problems between the shock chord knot, the snap swivel, and the BT wall.

For mid power, I use an eye bolt with two nuts. I drill a hole, and immerse the whole shebang in epoxy inside the BNC, leaving only the eye exposed.

 

[sandman]

I always puddle the glue over the loop where it meets the cone too.

One of the benifits of turning your own cones, you already have a wood dowel in the cone to attach the screw eye to.

sandman

 

[limd21]

I like the two-holes-with-kevlar-loop idea!

One time I had a screw eye pull out on a flight, even thought it was glued in with Elmers. My theory is that the screw eye threads didn't have enough "tooth" (too fine). The balsa was too soft for me to simply trust using the same screw eye, and I didn't have any screw eyes with coarser, more agressive threads. The idea I came up with was to fashion my own out of a coarse-thread 1" drywall screw and a bit of steel wire wrapped around the shank of the screw, just under the head to form a little loop. It's crude, but it's held up to many flights since.

 

[flying_silverad]

I screw it in, remove it and fill the hole with thick CA. Screw the eye back in and then soak the area around the eyelet with thin CA. Never had one pull out yet!

 

[powderburner]

If you are concerned about eye-screws pulling out, you can get substantially more grip length by using small cotter pins.
I drill a hole into the balsa about the same size as the shank of the pin. Squirt in some thin epoxy, follow with the cotter pin. The little loop that sticks out the base of the nose cone is plenty strong for clipping on a snap swivel.
The length of the cotter pin (inch? inch-n-a-half?) gives lots of surface area for the epoxy to get hold of. If you think the pin needs a little more roughness you could use side-cutters to make some notches along the length.
I have never had one of these pull out.

 

[Johnnie]

I use thin CA after the screw comes out. I let that sink into the threads good, then use thick ca to glue the eyebolt in.

 

[eugenefl]

Jeez...I didn't think there were *that* many ways to attach a screweye to a balsa cone. Well, since everyone as a different way of making the wheel round, I figure I'd chip in with one of my methods.

Ready? Ok...what you want to do is insert the screweye until the base of the screweye is nearly flush or buried into the base of the balsa. Run a "puddle" of epoxy/yellow/CyA over the base of the screweye and cone so that the bottom of the screweye is slightly submerged in the glue. This way, the screweye is a part of the base of the cone. Typically, the glue forms a "cap" or disc on the surface essentially trapping the screweye in place.