He said he had always liked that particular store, and had intended to own a retail shop one day. "I've always liked the old things, and history."
He's in the right trade and the right building. Jewellery manufacture hasn't changed much in 100 years, he said.
"We still do everything by hand."
Walking into the store is like stepping back in time. The original black-stained kauri cabinets and fresh flowers surround you.
Up the narrow and well-worn stairs are workshops and storage rooms with walls of the original dark, unpainted timber. Benches are set up with leather aprons to catch the gold and silver dust that falls as jewellers work.
The building was designed by Wanganui architect TH Battle, and will need earthquake strengthening. Mr Williams' workshop was a narrow room upstairs with a north facing window and single overhead light.
When the store opened in late February 1912 it was one of two elite jewellers in Wanganui. "We handle nothing tawdry," its advertising said.
About half of its current business is manufacturing jewellery, including making items to order, resizing and remodelling them and engraving using a new high-tech machine.
Mr Sell, trained jeweller Samantha Hanna and apprentice Jesse Bisset do that work.
Mr Sell and his wife Penny do the administration, and shop assistant Helen Davies takes care of the retail side.
That had changed a lot in 100 years, Mr Sell said. J Williams used to sell a lot of non-jewellery items - silver brushes, tobacco boxes, flasks and manicure sets for example.
These days the shop has glassware, watches and jewellery for sale, and when it comes to jewellery people are much more focused on brands and fashion.
The business was founded by James (Jimmy) Williams. He was a watchmaker and JP in Waipawa and moved to Wanganui in 1903.
He had jewellery stores in two different places before having the present building constructed. His son Joseph (Joe) took on the business after him.
When Joe's health failed he asked his daughter Wanda to return home from her job in London and take over. It wasn't her first choice of occupation but she did it well.
Miss Williams, as she was known, became a Wanganui character.
In 1974 she made the first major change to the shop, a double window for the front that greatly increased the display area.
When she decided to sell the store one of the accountants advising her suggested selling it to a chain.
The story goes that Miss Williams rose to her full height of five foot nothing and replied: "Over my dead body". There was laughter, but everyone knew she was serious.
She died in 2006, but would have approved of the present owners and the second major change made to the business.
That was bringing some of the manufacturing jewellery work downstairs, to be done in the shop as customers watched. The move was made in 2007, as part of a general revamp.
Mr Sell said that meant getting rid of some of the beloved cabinets, but people liked the change.
These days the "messy stuff" such as polishing and remelting is done upstairs but customers downstairs can still walk in and see jewellers peering intently at tiny objects as they go about their work.
