If your trailers are dry vans or china tops, get a pneumatic chisel one with a 2 inch stroke to pop the heads from the rivets. Re- profile the chisel to take on the profile of a wood chisel, once you start this job you'll get the idea why this new profile works better against the soft sheets of aluminium.
The new profile will not dig into the sheet and it works its way under the head of a rivet, as the chisel begins to wedge itself under the rivet head it will snap the head off. By working in a straight line with the rivets you're going to rip ten or more heads off in one run. If you had longer arms you could shear off rivets by the yard.
To avoid operator fatigue on the guy using the pneumatic chisel reduce your air pressure to 60 or 80 PSI.
After the rivets have been worked I do not spend any time removing a sheet, when everything is done I"ll keep bumping the trailer from a corner soon it begins to wobble and fall apart. This give you nice stackable sheets. and clean beams.
If the trailer has ribbed flooring have someone with an XRF check it, it maybe magnesium which has better wear resistance over aluminium. You may also find that magnesium ribbed flooring has only been placed where a fork lifts tires would travel the length of the trailer.
Now that the upper half has been removed you have the nasty part to deal with, the large aluminium beams under the floor that have a lot of steel rivets holding steel gussets. I heat the head of the steel rivet then burn it out. If you just cut the head off then you have to fight to remove the shank.
Fortunately the sheeting used for roofing is usually in one long continuous sheet and you will not have an excess of sealant to deal with. I heat the tar like substance then use wide blade ( spade ) in the pneumatic chisel to remove the crude. You may have to fabricate your own spade, I save all my broken chisels for such projects to re-purpose the shanks.
Aluminium and steel are not compatible materials, where to two metals meet you'll find that electrolysis has taken its due course. I use this incompatibility of the tow metals to my advantage by using my arc welder cranked up, when the welding rod is touched to the steel head of a rivet it will arc where it pass;s through the aluminium and burn a very large hole. Gives off a lot of white smoke so use this procedure at your own discretion.
Sometimes when doing this the steel rivet sticks to the rod and falls out of the hole when retracting the rod.
A
plasma cutter works but is slow in comparison to shearing the rivets off, and you can get aluminium cutting blades. Some guys will tell you to install a wood cutting blade in backwards.
Once I cut up some electric hydro bus's with my arc welder, to get some life out of the rods by soaking them in water. With the welder set at a high amperage you just drag the rod across the aluminium sheet you get a very ragged cut and the cutting goes very fast, if you can deal with the white smoke.
For a remote area with out electricity I still would use the welder.
Also whenever I'm dismantling a large aluminium truck cab with sleeper, these have a ton of steel rivets in them. I prefer using the welder to burn out those rivets.
This is how I dismantle trailers, you will have to figure what works for you best.
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