Hello JC,

I had a similar problem, what I did was to glue two pieces of balsa sticks on either side where the horn would sit, then filled it with hysol. I also applied hysol to the bottom and sides of the control horn to make sure is wet. then inserted the part in to the cavity. The balsa sticks need to be about 1/4 " high to build the dam for the hysol. True hysol does not run, but the dam will make sure it stays put and give you as much surface contact as possible when you insert the control horn.

Hope that helps.

Regards,
Mike