"Superglue is useful stuff, all right," he says, which makes me wonder what luthiers did before it was invented. Evans smiles and opens a jar of what looks like nothing so much as raw sugar, though a bit shinier and more golden.
Made from the hooves and connective tissue of various creatures, this is the stuff that gave rise to the expression about sending a broken down horse "to the glue factory". It's truly ancient technology: records of animal glue go back 4000 years. And Evans says luthiers love the stuff because it sounds so good.
"It's more resonant because it goes brittle-hard," he says. "It's ridiculously strong and you can manipulate it - a bit of heat reverses it so I can warm it up and it will release."
Unsurprisingly, perhaps, it smells nice too (Sammy loves the smell). And older readers would remember the taste from when they licked postage stamps: "A little bit of warmth, a little bit of moisture and it goes soft."
It occurs to me that, with the exception of an electric polishing machine, most of the technology in the room would seem familiar to Evans' renaissance predecessors. Shellac, made from a resin secreted by bugs in India and Thailand, is his finish of choice as it was for them. People call it French polish, he explains, but actually French polishing is the act of applying it.
"A lot of modern guitars are sprayed with polyurethane, which is what you paint cars with. It's really hard. It doesn't fade with UV light, but it doesn't sound very good either. You're stifling the vibrations with a thick coating of goo, whereas something thin and hard will enhance the sound."
A Baroque-era luthier would recognise most things in the workshop, Evans says, except the plastic handles on the chisels.
"He could start work tomorrow - and I wouldn't have to pay him much either."
A lifelong passion for tinkering - "Meccano is a wonderful thing," he says - was what got Evans into the craft. "I was always playing about with things when I was a kid and then I started to play a guitar and it seemed like a good idea to stick the things together."
Needless to say, he plays too, quite well, I imagine. When I ask him if he's any good, he hesitates before saying he can "get around a guitar" - the kind of modest comment that only good players make.
"I play in a covers band," he says, "but most luthiers are failed musicians."
Before I go, he shows me a 19th-century instrument that he's in the middle of restoring. He describes it as "fairly well rogered", which is something of an understatement. But a striking feature is a deep crater above the sound hole, made by the propped thumbnail of a finger-picking player.
"That will stay," he says. "Damage is fine as long as there's a story attached. You have to show respect for the instrument.
"The guitars I like are the ones with stories, the ones that granddad used to play and they have been in the cupboard for 50 years. Or the Les Paul that arrived in New Zealand having been sold to fund a Russian bride. They're the ones that have a connection."
