The basic principle of a lock-on is to lock yourself onto something so that you cannot be easily physically removed. That something can be another person or something fixed. The best way is with a climbing carabina and a chain or rope around your wrist. The important thing is to make it very difficult for the police or whoever to cut your lock-on off. Thats where the fun part comes in, covering that lock-on to make it very difficult to get to, thus delaying the authorities and making your blockade as successful as possible. They will possibly have access to specialist equipment.
Simple steel lock-on tubes are great but can be cut into in 20 minutes with a specialist drill head. The yellow pipes with a 2 cm thick wall are also great because the plastic actually melts around the drill head making them very hard to get into.
To make an oil drum lock-on you simply need an oil drum and some piping — preferably steel — which is just wide enough to fit your arm in and no more, cut so that it is as long as the barrel is wide. Drill a hole in the middle of this pipe section so that a metal rod can be inserted, this is what you actually lock on to. Cut holes on either side of the barrel so that this pipe can fit in in such a way that two people can lock-on on either side. Then simply fill this barrel with concreate and all sorts of hell like scraps of metal (lengths of thick steal wire will hold it together), megamorphic rock (very solid rock), quartz and the odd diamond if you want to bling it up, lengths of shredded polyprop is also very good at stopping the break-up of concreate from the wrath of a jack hammer. If you wanna be real hardcore putting in canisters of camping gas or lighter filler make the cops quite reluctant to cut into them (or even just saying you have, they wont take the risk), this is of course pretty dangerous. It will take the most skilled cutting crew in the country at least a couple of hours to cut you out of there. Two people locked on is better than one because with one person they may just try to lift it out of there with a fork lift truck, two bodies makes this far less likely.
The “Baby barrel� lock on is much more portible, fitting into a normal ruck-sack this one is for the blockader on the go. Its just a steel lock on tube inserted into a small barrel lengthways, its a similar idea as the oil barrel lock on with the concrete mass surrounding where you are locked on to the other person inside the tube. It is a little easier to cut into but its portability and ease of construction makes this the one to have this christmas.
Portability is often an important factor. Being able to stash and camoflage your lock-on will help here but always have a plan B if it gets found. The police will eventually be able to cut you out, no material is unbreakable but the longer you can hold your blockade the more you will have achieved out of your eventual arrest. Happy blockading.