I bought both my 4412s and 4410s "pre-owned".
Both sets had broken grill posts , still lodged in the grommets . Tried all kinds of glues , nothing held. Tried melting both halves togeather , no joy.
Finally came up with a proc that is much stronger than original.
Took the broken piece of post and drilled a 1/16 hole from the flat broken part thru the rounded end. Then placed it as it fits against the grill frame and drilled thru the just made hole down into the grill frame. (opposite direction of first drilling)
found a standard paper clip , straightened it out and layed both ends togeather , parallel. Two thickness just fit thru the 1/16 hole. Had to twist it to go thru broken part, and extended about 1/2 inch extra.
Got out the glue , inserted the extended clip into the grill hole , added glue into the break area and tightened the broken piece and grill togeather.
There is a loop of clip out the top of the broken peg , you just snip that off and WOW , that peg is strong now...never to break again...
takes 3-4 minutes.