The electric fuse connects to the battery, Abu Suleiman shouts "Allahu Akbar!" and the gas canister explodes, tearing up the road just a few kilometres (miles) from a Syrian army position.
For the rebel chief, whose men control a mountainous region of northern Syria, preventing the army from using this route near the Turkish border is a matter of life or death.
"I have cut off three roads into the village that they still control, so they now only have one and we can attack it," says the bearded 35-year-old, from Hama, whose father was killed in a 1982 massacre of Muslim Brotherhood rebels.
To supply his men with weapons, Abu Suleiman buys Kalashnikov assault rifles from mostly Lebanese arms traffickers, but for the explosives needed to blow up the roads and strike army tanks, his group turned to the Internet.
"I found what materials were needed to build a home-made bomb on the web, I copied the information onto a memory stick and brought it here," explained one of his men.
Abdullah is builder by profession, but was an army bomb expert during his military service. He is in charge of the workshop that produces the rebels' home-made bombs -- a bare room built from breeze-blocks near a rebel safe house.
Inside, aluminium nitrate, fertilizer and diesel fuel are mixed together and heated to create an explosive paste, and the detonators are then made from small tubes filled with the paste and wired up to an electric fuse.
"It's not very difficult, and with heavy equipment we have already managed to stop the tanks," said Abdullah, who opened his laboratory last July, four months after the anti-regime protests and bloody crackdown first began.
"Stopped, not destroyed. We damage the tracks so they can't advance. To destroy the tanks we would need something more powerful, which we don't have. But we are stopping them, and they are starting to get scared."
Tools and materials lie on the ground -- drill, pliers, batteries, metal, welding machine. Car alarms are used to make remote control detonators.
In the corridor, three gas canisters filled with explosives are wired up and ready to use. Five cartons of aluminium nitrate lie in a pick-up truck outside.
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Abdullah also makes bombs from 20-centimetre (eight-inch) metal pipes, welded at both ends and covered with pieces of metal for shrapnel.
"It is dangerous, it's true ... You have to be careful."
In a nearby house, he points to the walls that were shaken and the ceiling blackened in an accidental explosion.
"Just 200 grammes. It blew up while we were making the mix ... Luckily it was on a plate, and we were only lightly hurt. If it had been in a tube we would have been killed."
The rebels use the same explosive mix to build hand grenades -- a piece of metal tube closed at both ends with a wick sticking out.
On the road where the rebels detonated the gas cylinder wedged inside a drainage duct, Abu Suleiman rushes to inspect the damage. On the right, the road is blown away, but on the left it is merely damaged.
"Quick! Bring me another!" he orders his men.
Another bomb is inserted in the tunnel, a car approaches within sight of the armed men, does a U-turn and disappears, the men run for cover and another loud blast rings out.
This time the crater is huge and the road is impassable.
In a small village below, a.armed residents emerge on their doorsteps.
Abu Suleiman makes the victory sign and shouts: "Up yours, Hafez al-Assad!" father of the current president, who was in power at the time of the Hama massacre, an event that for so many defined the brutality of the Assad dynasty.