"If I can help preserve the memory of another one of them, then I should."
Operation Chastise, now better known as the Dambusters Raid, was an attack on German dams carried out on May 16 and 17, 1943 by the Royal Air Force No 617 Squadron.
They used a specially developed "bouncing bomb" invented and developed by Barnes Wallis.
One hundred and forty-four young men took off from RAF Scampton in East Midlands and 56 failed to return, all but three of them sacrificing their lives.
"The raid is a remarkable story of determination, innovation and bravery," Mr Stone said.
"I felt compelled to pick up my brushes and record these brave gentlemen and what they represent for posterity."
The other survivors are Bristol-based Squadron Leader Johnny Johnson and Canadian Flight Sergeant Fred Sutherland.
Mr Stone has already completed a portrait of Squadron Leader Johnson, who was a bomb aimer from the original crew.
He is in Tauranga this week to complete a study of Mr Munro, and will complete the large full size portrait on his return to London.
Mr Stone plans to visit Flight Sergeant Fred Sutherland in Canada later this year.
The three men had been initially reluctant to sit as they were modest men, but had agreed to do so as a memorial to those who were lost or have since passed on.