I'm building a Great Planes Trainer 40, and the plans call for fiberglassing the join of the left and right wings. I've done fiberglass before, so I'm OK with that. But the plans also tell me to install the aerilon control torque rods *before* fiberglassing. How in the heck do I keep the fiberglass/epoxy from gluing those rods in solid??

The plans says to drop a few drops of hot wax on the pivot point, but as I recall fiberglassing is a pretty messy business. How will a little bit of wax help? Won't I just wind up with a blob of wax fiberglassed over and bonded to the metal torque rod? Am I expected to carve the fiberglass away after it's hard?

Or do I keep the fiberglass about 1/2" away from all these moving parts by careful trimming of the cloth prior to application? That's not what the plans show, but it seems like the only safe course of action to me!

Thanks for any advice!

Charles.

Charles,

Do the underside of the wing first. This is where the main stress point is anyway.
When you lay out the strip of glass cloth, start around 1/2" behind the torque rods, work your way around the underside and then once you come around the leading edge and up to the topside, stop another 1/2" short of the torque rods.

This will give you ample strength for your Trainer 40

Hope this helps

Ari

Do I cover the top and bottom in one long piece of fiberglass?

So you're saying trying to snuggle up the fiberglass to the torque rods really isn't necessary. GOOD. I can handle that!

Thanks!

The hot wax will run down inside the torque tube and seal the openings. That will keep the glass resin from sticking to the tubes and rods.

You are right one. Cut 3/4" holes in the cloth in the proper position prior to application. I then glass the area very carefully aroung the opening leaving lots of "unglassed" area which is not seen or needed for strength. I do it with a single continous piece with the "seam" on the hidden side.

I don't use the wax thing but do, but when you are worried about epoxy sticking to something important like the torque rods, I use a light coating of vasoline applierd with a Q tip.

I am glad someone brought this up, because I have a question..

I am going to have to glass a wing set pretty soon on my venture 60. Last time I did this (per the manual) it bubbled all over theplace, and looked like heck.

Can I do it this way (I don't have any spray adhesive). Can I lay down a thinned layer of epoxy on the area I am laying the glass on, then lay the glass on to the epoxy. When it dries, I can then brush on epoxy on top of the glass to saturate it... What do you think?

Drape the glass over the wing joint. Pour on a bit of epoxy about the size of a 50 cent piece. Squeegie it out in all directions. Just enough pressure to push throught the glass and into the wood. Spread it out till it looks dry. Pour another bit and repeat till it's done. Let it harden . Put on a second coat and repeat. Spread it out till you can see the glarr fibres. If it looks shiny it's not spread out enough.

I'm sure there are dozens of different opinions but just to put up one more you might also try just usins thin CA to glass it. I attached a sketch of how I did mine when I glassed it.

I used 4" wide med tape and started the leading edge of the tape just behind the torque rods and cutting two small holes in it to go over them. I tacked it down and pulled it tight as I glued it in one long strip all the way around back to the torque rods.

Again I have used both ca and epoxy. The CA seems to bond just as well but leaves a gritty textured surface. The epoxy smooths out allot better but it's harder to pull the tape tight, keep ut from bubbling and get it smooth. (IMHO). The CA also saves some weight if thats a concern. Just a thought.

First I draw a line on the balsa where the edge of the glass will go. Using masking tape I tape off the line.

I use slow epoxy and brush a thin layer on the bare balsa. Then I apply the glass using a playing cards to "press" it down into the wet epoxy. Once smooth and before it drys I add a thin top coat of epoxy to to the glass using the playing card to squeege, smooth and remove any bubbles paying particular attention to the side that will SHOW. As the expoxy starts to set-up remove the tape leaving a clean edge. AS you know alcohol will remove the wet epoxy from your fingers or any mistakes.

Gentle sanding and alcohol cleaning of the cured epoxy will greatly increase the iron-on covering adhesion.