Mad Max Modifications: Improvised Armor for Vehicular Platforms, by A.D.B.

Tuesday, Jun 11, 2013

Recent conflicts overseas, namely the wars in Afghanistan and Iraq, have shown the usefulness of hardened vehicles in environments where governments were unable to provide for the security of the public or governments ceased to function at all.  Lessons in vehicle defense were hard learned in many cases, however the ability to freely maneuver under adverse conditions (such as those that may be encountered post-SHTF) is a much needed capability.  Improvised systems and designs based on proven engineering methods to defeat small arms and small improvised explosives can be adapted for use by the prepared individual to provide for a higher degree of security in movement.  The basis for all designs examined will focus on protection balanced with mobility, as any truly purpose built armored vehicle has to balance mission accomplishment with adequate levels of protection.  With materials readily available to most American consumers, a vehicle can be equipped to perform a wide range of operations from logistical convoys to patrols through potentially hostile territory.

A look at modern armored vehicle construction and what it is designed for is helpful in understanding the engineering behind defeating various weapons, and can be scaled to fit just about any platform imaginable.  For instance, a modern Mine Resistant, Ambush Protected All-Terrain Vehicle (MATV) has several aspects of its armor built to mitigate shape charges and improvised explosive devices (IEDs) that detract from vehicle application and maneuverability, like its limited field of view.  The hull shape is designed almost like a v-hull boat to help direct energy waves from explosions around the occupants of the vehicle, but almost in every case this results in suspension and axle components being separated from the vehicle.  While the occupants may still be alive, the vehicle is most certainly useless for transportation unless it’s repurposed as a gondola car.  The compromises made with most commercially available armored vehicles balance the level of protection, mobility, cargo capacity, visibility, offensive capability, and survivability.  The more purpose built any one type of vehicle is, it tends to perform exceedingly well in one or two of the above areas, but suffers in others.  Mission type and availability of components will play the largest roles in armor design, such as cargo trucks retaining load capacity may not have the same protection levels due to lack of space and vehicle size.  With improvised armor solutions, the highest levels of protection will sacrifice the speed, mobility, and longevity of the equipment, but do have their application.  The lower levels of protection may offer an additional security measure for longer range reconnaissance patrols or cross country movement where enemy contact is unlikely and the extended range and maneuverability of a lighter vehicle are more advantageous.

An in-depth study at threats encountered and ways they are handled will provide the foundation for whichever armored application will work best, then an analysis can be made as to the materials and construction for each protection measure.  The various threats most likely to be encountered in a post collapse society or one without the rule of law are as follows: small arms fire, improvised explosives, incendiary weapons, low-level conventional explosives, and a collection of terrain or environmental threats.  The below breakdown will list the threat and what engineering components are implemented to counter them; these engineering designs are best employed with tactics, techniques, and procedures (TTPs) to provide the highest degree of protection, however those TTPs are better tailored to situational and individual conditions than covered by a generic threat response.  For every imaginable conflict, a TTP should be developed and practiced by those participating in the operation to ensure the highest probability of success. 

Small Arms Fire:  Small arms are defined as those that can be operated by an individual and are man-portable, such as conventional rifles, shotguns, and pistols.  Light to medium machine guns also fall in this category, as the projectiles are not designed as anti-armor (in most cases) unlike their heavier brothers.  Historically, hardened steel or iron has proven effective at defeating small arms, and most any metal an inch thick will protect from .50 caliber rounds on down.  It is impractical in most cases to use inch-thick armor however, and improved designs are readily available that are lighter and more easily adapted to vehicles.  Kevlar is one such material, which is a thin nylon fabric that is matted many layers thick to provide ballistic protection.  This can sometimes be found in industrial applications where ballistic shielding is required around equipment, but is often prohibitively expensive.  A more easily found replacement is bulk nylon cloth with either stitching or resin added.  While not all nylon fabrics share Kevlar’s anti-ballistic properties, a thick (one inch or more) matting of nylon either tightly woven or bonded with resin or epoxy will offer some flexible and light-weight protection from pistol, shotgun, and some rifle rounds.  Bolts of fabric can be found at places like Wal-Mart, and each 52”x40 yard bolt, along with two gallons of fiberglass resin, could provide enough materials for one smaller vehicle packed between the door panels and sitting on top of the floor boards or roof.  A side note on Kevlar and anti-armor rounds: the M855A1 5.56mm NATO ball ammunition, and other types of military sabot/SLAP ball ammunition contain tungsten or steel penetrator tips.  These are very effective against mild steel and Kevlar, which is why many small arms protective inserts (SAPI plates) are ceramic.  The M855A1 is rated to penetrate 3/8” of mild steel, so consider this in material selection.

Improvised Explosives:  Any device which uses a rapidly expanding propellant or explosive charge to inflict damage falls within the “improvised explosive device” category.  This includes a wide range of devices, from black powder in a pressure cooker to a howitzer shell wired for command detonation.  Regardless of construction or means, there are two principal threats with IEDs: one is the concussive blast wave created by the localized pressure from the explosive, and the other is primary and secondary projectiles in their many forms.  Projectiles range from shrapnel and lead shot to heavy-metal rods, as is the case in shaped charges.  Concussive blasts are best defeated by channeling their pressure away from or around the vehicle, which is very difficult to accomplish without a purpose built hull.  Mild steel or magnesium-alloy steel in over one-inch-thick continuous pieces are used in MRAPs, and would be difficult to fabricate at home.  However, the convex design of many bulk fuel tanks (like propane and gasoline) could be cut to fit many different vehicle sizes and provide a measure of protection against concussive blasts.  This will reduce the ground clearance of the vehicle and may have adverse effects on drive train performance due to excessive heat build-up.  None of the purpose built vehicles will place armor over the exhaust systems because of this, so be mindful of exhaust routing if under body armor is used. 

For protection against projectiles, the same techniques are employed as those to defeat ballistic threats with the exception of shaped charges.  Shaped charges employ a directive metal cone, normally copper, to multiply and focus blast pressure.  The explosive is focused in such a small area that the pressure wave generated acts upon metals as if they were a fluid, and under the principals of fluid dynamics, incompressible.  Imagine an explosive force that renders a normally solid metal hull to act like a shield of water with hollow core.  The pressure exerted on the exterior would allow the shield to rupture and transfer energy to the hollow center where the force becomes a concussive pressure wave.  Glass and ceramic layers were found to be incredibly effective in disrupting shape charges, as when the explosive pressure makes contact with the ceramic plate, the concentrated path of the charge is disrupted and not able to transfer energy like a fluid, which shields an inner skin of metal from penetration due to the blast.  These can be improvised by using ceramic flooring tile, and while these tiles may not be heat tempered, they are a light-weight addition that can also provide for additional ballistic resistance.  Using thinner (3/16” to 3/8”) sheet steel, these tiles can be sandwiched in between for door skins and passenger or engine compartment shielding.

Incendiary weapons:  Thermite and Molotov cocktails are easily improvised by nefarious groups and can be devastating weapons against vehicles, as many components and cargoes are extremely flammable.  Modern tactical vehicles are designed with automatic fire suppression systems, as IEDs, incendiry bullets, or tracer bullets can ignite the vehicle fuel or cargo.  These systems are generally high flow dry powder or CO2 systems that would prove difficult to improvise without a pre-staged stocks of fire suppressant tanks.  Insulating the vehicle armor on both sides can provide a measure of resistance until a conventional extinguisher can be used to put out the fire.  There are plenty of light-weight and flame resistant coatings available in mat and spray on applications, the easiest to be found is in junk yards as under-hood insulation.  These high density mats are not flammable and can easily be cut and glued onto the interior of armor paneling to provide the vehicle occupants the time necessary to escape from a danger zone without risking vehicle systems or excessive passenger compartment temperatures.  Two part urethane coatings, such as truck bed linings, have also been found as a great exterior coating for armor that assists with ballistic and incendiary protection.  Almost all new production armor vehicles use these coatings on the exterior of the entire vehicle, and have the benefit of protecting the armor from corrosion and being easy to apply.  While none of these will stop thermite from burning through due to its extremely high temperatures, they will provide the operator with valuable time to deal with a situation.

Low level explosives: While it is difficult to imagine the possibility of encountering land mines or howitzer shells in a post-collapse situation, encountering pipe bombs, black powder, or Tannerite powered devices would be inevitable at some point.  These explosives do not function like a shaped charge or high explosive, but instead use the rapidly expanding gas pressure from the charge combusting to blast secondary projectiles or cause their enclosure to rupture and fragment.  These threats are handled in much the same way as ballistic projectiles are as the accompanying blast pressure wave is negligible.  Steel sheets with a three to six inch gap in between filled with packed sand or concrete work very well to prevent fragments from penetrating, but these enclosures can be excessively heavy.  If a smaller area, such as an exposed gunners position in the bed of a truck, has the space and capacity, this is a viable and attractive option that provides better and more resilient protection than sand bags or other alternatives that may not withstand the vibration and flex that a mobile platform encounters.

Terrain and environmental threats: One of the most often encountered issues with mobile armor is the cumbersome and heavy design of a vehicle that may need to operate off road or in less than ideal road conditions.  Traction and suspension issues that are common in mud, sand, and snow are magnified if the vehicle is substantially heavier and has less suspension flex.  Additionally, road conditions that stress the suspension will push components past their failure points with the added weight of armor.  Upgraded vehicle components are necessary to counter the issues encountered with the additional weight of armor if any sort of longevity is expected out of the platform.  Suspension upgrades should include heavier-duty and longer travel springs, larger shocks, and heavier duty axles/axle shafts.  Tire size and load range should also be increased; weight is better distributed across an area if the tire is wider and taller.  Drive trains should be toughened up with heavy duty transmissions and additional cooling systems.  Running several small oil coolers for the engine and transmission will provide extra fluid capacity and allow one to be bypassed if it is punctured.  Because the armor places more load on the engine, consider upgrades to engine power and a free-flowing exhaust, which will assist in keeping the engine cool as well.  High temperatures have been known to disable armored vehicles that were not equipped to cool a harder working drive train. 

Now that the treats and appropriate countermeasures have been identified, a closer look into choosing and up-armoring a specific vehicle can be investigated.  While there is no “one size fits all” option, for the typical family-oriented prepper nothing larger than a one-ton (or perhaps flat-bed) truck would be practical.  For larger vehicles, there are more available methods, but they fall well outside the scope and price of most individuals’ needs.  One-ton trucks and SUVs are common and readily available now, with many preppers already owning one, so the focus of specific modification instruction will apply to these but many modifications can be scaled down for smaller applications.  Before considering armoring a vehicle, ensure that it is mechanically sound and all regular repairs are completed.  An invincible truck with a seized engine is a great land anchor but a poor tactical vehicle.  If practical for your application, the installation of a heavy-duty lift kit and larger all-terrain tires will make for a better armored foundation.  If the towing and payload capacity would be exceeded by the additional armor weight, installing air bags to the factory or aftermarket springs will assist in handling the extra load.  A note on springs: the military was in a period of transition throughout the war, and both leaf sprung and coil sprung variants of the same vehicle could be found.  The same is true in many cases in the civilian world, many manufacturers have stopped using leaf springs both front and rear and now use coils or torsion bars in the front end.  While coil springs provide better on road handling and a smoother ride, they are not as resilient to overload or the constant stress of armor.  The military found many stock coil springs fatiguing prematurely, and in some cases breaking into pieces.  Leaf springs did not suffer many of these issues regardless of the load placed on them, and although they do not offer the same performance, are often a better choice for armored vehicles.  The same thing was found regarding solid “live” axles versus independent suspension, where the solid axles required fewer (if any) upgrades to handle the additional stresses, but independent suspensions suffered regular failures.

Adding the lightest level of armor can be accomplished with little more than scrap sheet steel and bolts; simply find 3/8” thick plates and bolt them on top of existing body panels.  Use twice to three times as much hardware as normal for the application, a good rule of thumb is a bolt every 6 inches along the edges of the panel, two inches away from the edge.  While not as strong as a continuous weld, this will help prevent distortion of the panel due to explosive pressure and aid in longevity.  All hardware should be grade 8 if it’s available, lower grade bolts can be sheared off with small arms fire.  Another easily applied light armor option is the “L door,” where a panel of steel is cut to fit the dimensions of a door exterior including the glass, then notched in the front towards the A pillar to provide visibility while still offering protection for the head and shoulders of the occupant.  These can be hung from a channel bracket that rests on the window frame of the existing door, and have the benefit of being easily installed and removed.  With subsequent levels of armor, the standard framing and hinges for the doors will not support the weight, so consider welding the doors to the frame or removing the doors entirely and mounting a heavier duty frame and hinge in place.  The most neglected component of door armor is the latching mechanism, which has to be just as strong as the hinge.  A single point of contact is not enough for a heavy door, so consider a multiple bar lock style of latch, like one would find in a safe door.  For upgraded protection, the inner door can be gutted of window glass and other components then paneling, like aluminum street signs, can be added to the interior side to create a large cavity within the door.  This can then be filled with sand, ceramic tile, nylon/Kevlar matting or a combination thereof.

For hood, fenders, and other body panel protection, consider using a mix of scrap steel sheets bolted to existing frame or body parts and tiles mounted with brackets or channels in the steel.  If the tiles are mounted in a channel or with brackets, they have the advantage of being easily replaced if broken by incoming rounds.  Do not place solid sheets of metal over the grill as this will cause overheating of the engine and under-hood components.  Louvered steel or iron can be easily made to fit over these sensitive areas by cutting the steel into two inch wide strips and bolting or welding them into a frame at a 45 degree angle.  Spacing can be changed to add more protection but at the cost of airflow.  Sand bags stacked on the hood or along the inside of the vehicle may be a field expedient method for minimal protection, but this will prove very heavy and cumbersome without providing a substantial degree of protection or allowing for heat transfer from the engine to the ambient air.  Instead, mild steel and tile can be used to protect the floor boards and interior of the vehicle without expending cargo capacity and space. 

Field of view and transparent armor have been a weak point for armored vehicles since their inception.  Due to the limited availability and excessively heavy weight of transparent materials, most applications restrict the amount of glass as much as possible, often sacrificing visibility for enhanced protection.  In modern designs this has still held true, mainly due to the material limits and current engineering technologies.  Ballistic glass has not changed much since the advent of clear polycarbonate, or plastic based transparent materials.  These are employed in layers with tempered (or heat treated) glass to create a dense transparent panel that can withstand multiple high powered rifle round impacts.  The sheets of glass and polycarbonate vary in thickness but are typically ¼” to 3/8” thick, and between three and 12 layers are used depending on level of protection.  The frame is critical to effective transfer of force from glass to vehicle body, and should be sufficiently over-built to accommodate the level of threat expected.  Overall size of the glass also plays a role in resistance to forces, such as IEDs, as the larger surface area of solid glass increases the stresses placed on the frame.  Smaller is better when mounting transparent armor and will save weight while increasing strength.  Custom ballistic glass makers can be used to provide prefabricated transparencies of just about any size, however basic protection can be accomplished by adding layers of Lexan (the most common brand of polycarbonate used) to existing tempered safety glass.  Two layers of Lexan, one on the exterior and one on the interior, bonded to the safety glass with pressure sensitive adhesive will provide protection from shrapnel and low powered cartridges as well as large hand-thrown objects such as rocks or bricks.  Any more protection will require a custom frame as the existing A pillars that support the windshield will not withstand a substantial amount of force or weight.  Using small residential windows layered with Lexan would work well and could be easily mounted in sheet metal fabricated for the doors for enhanced windows.  A note on working with polycarbonate is it becomes more flexible when mildly heated and can be cut with a hot knife easily, with masking tape on both sides of the material along the desired cut to preserve surface transparency and reduce the risk of fractures.

While practical welding, fabrication skills, and familiarity with basic automotive tools are required to perform the majority of these modifications, they are developed over time and with hands-on training in order for one to be proficient with their applications.  A good recommendation however would be to take a welding class at a local technical college, or failing that, purchase a hobby welder and practice with scrap metal at home.  Most heavy, armor grade steels will require the use of a 220 Volt or larger welder, wire-feed being the first choice and arc (or stick) welding being a cheaper alternative.  Heating many of these metals with oxyacetylene welding will weaken them, making it an impractical method for armor construction but can be used in place of a plasma cutter or circular saw if there is no alternative.  Bolting of armor pieces has been found an effective method, and is generally more viable due to the availability of hardware and assembly tools.  Locating scrap metal sources is critical to this endeavor; some universal resources could be dumpsters, shipping containers, storage tanks, rail cars, guard rails, and junk yards.  Use a magnet to check for non-ferrous metal, like aluminum, which is not ideal for armor construction and requires different welding methods.  If the metal is non-magnetic, it will not be suitable for most MIG or stick welding.

Having the ability to up-armor and harden your vehicle may be critical to your bug out plan or continued survival, and with the correct approach can be accomplished to protect your assets and provide enhanced security in a challenging situation.  Should the time arise when you desire mobile protection, employing these methods may provide you with the advantage needed to prosper where others fail and enhance whatever transportation plan you have in place.  Please research specific parts and attributes of your vehicle beforehand, and use appropriate protective equipment when welding, using hand tools, or going into unfriendly territory. 

Safety Notes: Never weld on a vehicle while the vehicle battery is still connected, as this will damage the vehicle electrical system.  And do not turn your vehicle into a Mad Max look-alike without first consulting your spouse as this may be hazardous to your health, especially if it is the one they use most frequently.  Lastly, remember to keep the vehicle's rubber side down.


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