"Not bad eh. I've been really scraping and doing it on the smell of an oily rag for a long time," the 53-year old said.
The stunning 3.2m board is sculpted from paulownia timber and bears a 23-carat gold "Rampant" heraldic lion.
Its flexible design, with a single concave that stretches from its soft-entry nose to its tail, enables it to reach speeds of up to 56 km/h.
The structure and method has been honed since he started board-making fulltime in 1994.
The Rampant, Mr Stuart says, is the pinnacle of what he has learned.
While he says the board is "so visually striking many people think it might be designed for artistic appeal alone", he denies that it's art.
"From the beginning, I made a solemn vow that I would never do anything to a board that wasn't solely for its functional purpose," he said.
"For the first 10 years or so I used to just paint them white - it was all about the ride.
"In this sort of discipline, art comes from the ride. If it works well, it will be enjoyable to look at."
In true surfing style, the father-of-12 philosophy major is a radical.
His boards and designs are often copied by some of the world's largest board shapers.
International board makers have been "handicapped" for the last half a century, he says, because they continue to stick with inefficient designs.
Longboards are "trendy", he said, but difficult to ride.
And so are short boards, which require high levels of athletic skill to make them ride waves well.
His boards, he says, glide better and are better-balanced.
"The result in water is really obvious," said Mr Stuart, who also uses 3D printing technology for high-performance, polycarbonate fins.
So what's with the US$1.3 million, or $1.5 million, price?
He says surfing deserves to have signature pieces - just as vintage wines which can fetch millions.
"I'm not going to justify the price. To me, it's just a number," he says.
"How much more is it worth to have something you really like? It's really a moot point."
And besides, it's worked.
Mr Stuart wouldn't say who the buyer was.
But all that hard work, sacrifice, has paid finally paid off.
"Success at last," he said. "It's been a long hard grind, but there's still been a lot of waves caught - a lot of fun. It's been a blast."APNZ
