On a heavy brooch, I’ve been putting one or two tie tack pins that
attach the brooch to and thru the (heavy) fabric with tie tack
clutches. This is inelegant and tie tack clutches are big. I’m
looking for method that is simple and keeps the brooch back tight
against the plane of the fabric, and is secure.
One mechanism I’ve seen and used for holding a large brooch (besides
two scatter-pin sets, which are less bulky, but also uglier than
tie-tack sets) is to make a double pin. Imagine a rectangle (the
brooch). Now put a piece of small tubing close to the top edge,
almost all the way across (like a normal pin back). Run a piece of
18 or 20 guage wire through it. Bend the wire at right angles on
both sides just where it emerges. You now have, in essence, an
oversized staple, held against the piece by tubing. Cut the ends to
length so that they reach almost to the bottom of the piece, put
hooks or catches to hold these (sharpened) wires. Clear as mud? One
additional thing-- you can put a little detour (a bumb outwards) in
the wire at the top. This may make it easier to insert, and allows
the whole thing to be fastened easily over a chain for duty as a
pendant.
I hope this is intelligible. If not, I’ll draw something and post
it.