thibor

Hello,

I'm building my first kit, it's a Top Flite Elder 40.

I'm in the final stage and have a question about the wingsaddle.

The wing has a round shaped leading edge and the wingsaddle is straight flat till it hits the former where the wing-hold-down-dowels go into.
I would like to fill the wingsaddle, so there is no gap between the rounded LE and the straight wingsaddle.

In the picture you can see the gap. (took the picture from a fellow builder here at RCU, hope mistermnkim doesn't mind )

I heard this is done by mixing epoxy with micro-balloons, but how do you get the shape and prevent the epoxy from going over the sides of the fuse?

Hope you can help.

Thanks,
Phil

reincarnate

Mix it so that the consistency of the resin/balloon mix is that of frosting. There isn't a ratio that I know of, so just keep adding balloons until the mixture is light and fluffy and peaks stand without falling. Kind of sounds like a cookbook instruction, huh? Anyway, before you apply the mix to the saddle, cover the wing surface that will contact the saddle tightly with Saran Wrap. Make sure it's stretched tight and doesn't wrinkle. Apply the mix to the saddle, using just a little more than you think you need, and then seat the wing in, and bolt down. Leave it alone until the mixture sets up firm, (time depends on the epoxy used, temp, etc) then remove the wing and carefully with a sharp blade, trim the excess mix from the outside and inside of the fuse. After that leave it set overnight so the mixture is completely cured. You'll find that the resin/balloon mix sands very easily. You can touch up any small voids in the same fashion.

thibor

Reincarnate,

thanks for the advice!!

Just wondering, after the mix has hardened, can I cover it, or will the heat make it melt?
I'm going to use Solartex

Thanks,
Phil

reincarnate

Won't melt. If it does, you've got your heat too high and the balsa may catch fire.

mikegordon10

I've done this same procedure with an uncovered model using clear packing tape on the wing. I lightly grease it with "veinerslidder" (Vaseline petroleum jelly).
Mix Epoxy and micro balloons to the consistency of peanut butter and apply it liberally to the wing saddle.
Carefully bolt the wing in place and then use your finger dipped in alcohol to smooth the fillet that is made on the outside of the fuse. You can get this very smooth with just your dipped finger and very little or no sanding will be required to cover.
After the epoxy mixture sets for a couple of hours take the wing off. Don't wait too long and then trim off the excess on the inside. Sand off the last 1/32" or so of the excess flush with the inside of the fuse wing saddle. If you don't want the fillet on the outside it's easy to sand it off flush with the outside.
If the wing is already covered you can just grease it with "veinerslidder" and continue on with the same procedure. The "veinerslidder" cleans off the wing covering easily with Windex or even just straight alcohol.
The epoxy/micro ballons mixture works best using a finishing resin (I like Z-Poxy) rather than an epoxy glue and by all means avoid using 5 minute epoxy cause it's difficult to sand and will also set up too fast to properly complete the procedure

thibor

Hey guys,

thanks for the replies, it doesn't seem that difficult now.

Thanks,
Phil

crossman

Thanks for the information guys. I have 2 planes on the bench right now that I plan to do this on. The tips will be very helpful. The sugestion about making a fillet with the finger sounds good. I hate sanding.