And then he got hooked on methamphetamine a 10-year addiction that ultimately led him to a Peninsula storage facility in July where he stole more than 700 pounds of law enforcement explosives.
For the theft and possession of explosives, Allan, 46, will serve a 51-month sentence, the maximum allowed within federal sentencing guidelines.
Allan's mom and brother sat in the front row of the courtroom Friday as U.S. District Judge D. Lowell Jensen of Oakland handed down the sentence, their expressions calm.
Even as Allan choked up while delivering a statement of regret to the court, his co-defendants and his family simply watched, relieved.
"It's the first time I've had hope he's going to be able to be helped," said his mother, Iris, a 75-year-old Concord resident, sitting in a wheelchair outside the courtroom. The sentence included a recommendation for placement in a federal prison with drug treatment.
On July 2, Allan, a Hayward resident, drove to the facility near Upper Crystal Springs Reservoir, cutting through two locks with bolt cutters and loading a stolen van with explosives.
Three days later, he returned with co-defendant Dean Utile, cutting through separate locks with a blow torch and an oxygen tank.
In two storage units, they found the explosives 700-plus pounds of C4, grenades, grenade simulators, detonation cord, dynamite, fuses and blasting caps.
On July 6, Allan gave some of the explosives to Timothy Dean Byrd, 36, and more a day later to Gregory Sherinian, 41.
In an age of heightened terrorist alerts, the crime jolted California law enforcement with the knowledge that a drug addict pulled off the crime with bolt cutters and a blowtorch.
"Thank God somebody turned him in," said Allan's brother, David.
All four men involved in the crime have pleaded guilty.
Sherinian received a 37-month sentence for his part in the crime. Byrd and Utile, 42, are scheduled for sentencing Friday.
Allan was indicted on 11 counts and reached an agreement to plead guilty on three; Jensen dismissed the other counts at Friday's hearing.
But the judge was unwilling to yield on the 51-month sentence, given how serious the offense was and the fact that the actual amount of explosives far exceeded law enforcement's initial estimate of 200 pounds.
Given the destructive possibilities, "we're just very fortunate they didn't happen," Jensen said.
Even Allan's brother said 51 months behind bars didn't seem like too much given the theft of such dangerous explosives in a post-9/11 world.
The Concord resident said he hopes his brother uses the time in federal prison to kick his addiction, to learn skills and to pursue his love of drawing.
David Allan is already compiling his brother's art cartoons made on the envelopes carrying letters to family and putting it up on the Internet. He calls the site "View from the Pen."
"He wants to change. He's tired," David Allan said of his brother. "He realized this is huge."
Contact Jill Tucker at firstname.lastname@example.org.