Extreme Flight 125" EXTRA 300 Assembly Manual page 5

6. Scuff the portion of the control horns that will be glued into the aileron with sandpaper
to remove the glossy sheen and clean with denatured alcohol. Mix up some 30 minute
epoxy (I prefer Mercury Adhesives 30 minute formula). Use a piece of pushrod or old
hobby blade to fill the slots in the aileron with epoxy. Coat the entire area of the horns that
will insert into the aileron and the bottom of the base plate with epoxy. Insert the horns
into the slot and push down until they are flush with the base plate. Use a paper towel
soaked with denatured alcohol to remove the excess epoxy. Insert a 3mm bolt through the
holes in the horn to insure proper alignment. Repeat this process for the remaining control
horns.