When toroids are mounted flat to a board, such as the ones in the A.L.T tuner, it is sometimes necessary to glue them down to the board. This can be a messy job, but I have discovered an easy way to do it with commonly available materials. Go to the craft store or to the craft department of Walmart, and pick up some hot glue sticks that are ¼" in diameter. You will use these sticks and a hot air gun (or your wife's hairdryer) to fasten the toroid to the board.
First mount the toroid on the board. In the picture below, I have mounted a
toroid on a pcboard using manhattan style pads.
Fig. 1 - Toroid mounted flat on pcboard
Now cut a piece of the glue about 1/8" thick and place it on the toroid as
shown in Fig. 2.
Fig. 2 - Glue on top of toroid
Now take the hot air gun or hair dryer and place it on its lowest setting.
Hold it about 3 or 4 inches above the toroid and glue, trying to hold it
directly above so that the air goes straight down. When the glue melts,
you are finished. Make sure that the glue melts enough to contact the board.
That is all there is to it. Be sure to let it cool before you touch it as
it will be very hot.
Fig. 3 - Toroid after the glue has been melted. Note the seal on the board
on the right side.