The exaggerated peplum in 22-year-old Amy Robson's winning dress was once a handbag purchased by her grandmother Sandra from an op shop in Perth.
The pair spent hours pulling the bag apart, then decorating it with hand-painted beads, before turning it into a key piece of the ensemble they created together.
"It's a hobby for both of us. We don't count the time," said Ms Robson, national winner of the 2012 Melbourne Cup Carnival fashions on the field competition.
Sandra Robson, dressed in cream and bronze, was at Flemington on Thursday to support her granddaughter.
"There's no time factor involved, it's just a labour of love," she told NZ Newswire.
The jersey print dress was inspired by an Alexander McQueen gown from about five years ago.
Sandra said she put her own personal twist on the iconic UK designer's idea when making the piece, which featured a high neckline and brown and orange colours.
The finishing flourish was an acid-yellow beaded ruffle - or peplum - that accentuated slender Amy Robson's hips.
"It was a brown-beaded handbag," Sandra said.
On her head, Brisbane resident Amy wore a black and yellow hat, which Sandra also made.
The ensemble was the result of many evenings spent painting brown beads acid yellow while watching fashion reality show Project Runway.
"Amy and I had quite a bit of fun painting those beads," Sandra said.
"The first thousand were the worst."
Ms Robson's prize package includes a Lexus convertible, a Myer shopping spree and a nine carat white gold pin.