TORONTO - A man arrested in connection with the violence-marred G20 summit had everything he needed in his home to make powerful bombs, his trial heard Wednesday.

Crown witness Crawford Anderson, an explosives expert who works with the Canadian military, told court he had no doubt Byron Sonne could have made devices to blow things up.

"It is my opinion that there were more than enough materials present to make explosives, and to make improvised explosive devices," Anderson testified.

At the same time, however, Anderson's testimony highlighted how many products and items that can be used to make bombs -- such as chemical cleaners, solvents and a hotplate -- are commonly found in many homes and easily bought at hardware stores or supermarkets.

"That is the difficulty with a lot of this stuff," Anderson said at one point.

"I have seen improvised detonators made out of cheap Bic pens."

When Crown lawyer Liz Nadeau asked about hydrogen peroxide, Anderson replied:

"It's the sort of bleach you would use if you wanted to look blond."

Anderson, who works out of Suffield, Alta., said "recipes" for explosives are easily available over the Internet.

For example, mixing ammonium nitrate -- commonly used as fertilizer -- with diesel could become a powerful bomb, he said.

Drain and driveway cleaners, sugar, vegetable oil, almond flour and PVC piping, among many other things, could all be put to no good by a determined chemist.

At times, Ontario Superior Court Justice Nancy Spies had difficulty following Anderson's chemistry and bomb-making explanations, asking numerous questions about detonators and setting off blasts.

"It's not unstable, it's just sensitive," Anderson said about one potentially explosive mixture.

Sonne, 39, who was arrested a week before the G20 summit in June 2010 and held for 11 months before getting out on bail, is charged with four counts of possessing explosives with abbreviations like TATP.

A plethora of chemicals, including various acids and dozens of hexamine fuel tables, were seized from Sonne's upscale Toronto home along with laboratory devices and electronic bits and pieces.

The Crown is not trying to prove that Sonne planned to blow anything up at the G20, only that he had explosives at home and a fascination with the summit.

He also faces a charge of counselling mischief "not committed" by, for example, publicizing how to climb the security fence set up at the G20.

Supporters of the self-described security geek say he was publicly trying to expose flaws in the expensive effort to protect world leaders.

He also says he was a model-rocket enthusiast and made crystals at home.

Clearly, the neatly labelled containers of various chemicals and the apparatus in his home went well beyond what most homeowners have.

Still, none of the chemicals appears to have been illegal, and the defence is expected to argue that none had been combined into anything dangerous.