Polyethylene vs Steel Body Armor: Pros and Cons

Why body armor material matters

When it comes to protecting yourself with body armor, the material makes a big difference. The two most common options are polyethylene (a strong plastic) and steel. Each has advantages and drawbacks to consider. While both polyethylene and steel can potentially stop bullets, they vary in weight, thickness, durability, cost and more. Understanding the pros and cons of each material is key to choosing the right body armor for your needs and budget.

Polyethylene body armor overview

Polyethylene body armor is made from ultra-high-molecular-weight polyethylene (UHMWPE) fibers. This thermoplastic is extremely strong for its light weight. Well-known brands include Dyneema and Spectra. Polyethylene body armor is typically soft and flexible rather than rigid. It's most commonly used in soft armor inserts that slip into vests or plate carriers. Hard polyethylene plates are available but less common than steel.

Steel body armor overview

Steel body armor uses hard plates made from high-quality hardened steel. AR500 steel is a popular choice that meets level III protection standards. Other options include AR550, AR600 and AR650 steel plates in various thicknesses. Steel body armor is known for its toughness and multi-hit protection. Steel plates are usually sold as a set to insert into the front and back of a plate carrier vest. Steel is also used for some one-piece "active shooter" style vests.

Comparing protection levels

Both polyethylene and steel body armor are available in different protection levels. Here's a quick comparison:
Material NIJ Protection Levels
Polyethylene IIA, II, IIIA (soft)
III, IV (hard)
Steel III
III+
IV
Polyethylene soft armor offers protection against handguns and shotguns up to level IIIA. Hard polyethylene plates can reach level III and IV. Steel is most commonly found in hard level III and IV plates for defense against high-powered rifles.

Weight and thickness

One of the biggest advantages of polyethylene is its light weight compared to steel. A polyethylene plate can weigh half as much while providing similar protection.
Material Weight Thickness
Polyethylene 2.5-4 lbs 0.7-1.2 in
Steel 5.5-8.5 lbs 0.2-0.3 in
However, polyethylene plates are much thicker than steel to achieve the same level of protection. Polyethylene level IV plates are typically over an inch thick, while steel level IV plates are around a quarter-inch.

Spalling and fragmentation

Spalling is a major concern with steel body armor. When a bullet strikes a steel plate, it can cause fragments of the bullet and armor to break off the inside of the plate towards the wearer. This shrapnel-like debris can cause severe wounds. Anti-spall coatings are used on most steel body armor to reduce this risk. However, the coatings can wear down over time. Spalling remains a potential vulnerability of steel plates, especially with repeat impacts.

Heat and fire resistance

Polyethylene has a lower melting point than steel. While still very strong, it can warp or melt if exposed to intense heat, such as from a fire or explosion. Once compromised, polyethylene loses its protective abilities. Steel plates maintain their strength and shape even at high temperatures. They offer protection against heat and flames that would damage other materials like polyethylene.

Cost and value

Steel body armor has a lower entry price point than polyethylene. You can find reliable level III steel plates for around $100 each. Polyethylene plates with the same protection often cost twice as much. However, many people feel the light weight and spall resistance of polyethylene is worth the higher price tag. It comes down to your personal priorities and how much you're willing to spend for the benefits of each material.

Multi-hit protection

Steel armor plates are known for their excellent multi-hit protection. A good steel plate can withstand a dozen or more rounds, even in a tight grouping, without losing structural integrity. This makes steel ideal for combat scenarios. Polyethylene plates also have multi-hit endurance but may start to lose strength after several rounds. Once penetrated in one spot, the surrounding area becomes more vulnerable to additional hits. The multi-hit capacity depends on the specific polyethylene plate design.

Comfort and flexibility

Polyethylene has the edge when it comes to comfort, especially for extended wear. Its light weight reduces fatigue on the shoulders and back. Soft and semi-rigid polyethylene panels are also flexible to move with your body. Steel plates are rigid and inflexible. The weight can become uncomfortable after a few hours. However, a well-designed plate carrier can help distribute the load evenly for improved comfort.

Buoyancy in water

If your tactical scenarios may involve water, polyethylene is the clear choice. The light, non-porous material is naturally buoyant. Polyethylene plates will float, making them suitable for boats and maritime ops. Steel plates will not float due to their weight and density. A tactical vest with steel front and back plates can easily cause the wearer to sink, restricting mobility in water.

Shelf life and durability

Both polyethylene and steel body armor can potentially last for decades if stored properly. However, steel has the longer shelf life and service life expectancy. Unlike polyethylene, the molecular structure of steel does not degrade over time. With minimal care like keeping them dry, steel plates can maintain their protective abilities for 20+ years. Polyethylene is more prone to gradual weakening, especially if exposed to UV light or harsh chemicals.

Magnetic signature

One potential drawback of steel plates is that they are magnetic. The steel can set off metal detectors, which may be an issue for some wearers. It's also possible for the plates to interfere with other sensitive electronic gear. Polyethylene has no magnetic signature. The thermoplastic material will not interact with metal detectors or other electronics.

Weather and temperature concerns

Neither polyethylene nor steel are significantly affected by most weather conditions. Both materials are waterproof, and the plates will not be harmed by getting wet. However, any cloth or foam on the plate carrier may absorb water. Both materials can handle cold and heat without reducing protection. But steel may feel extra cold in winter conditions if the plate directly contacts skin. The steel can also heat up in direct summer sun, though plate carrier padding usually prevents discomfort.

Cutting and drilling

If you want to customize your body armor plates, steel is easier to work with. You can cut steel plates to whatever size or shape you need with an angle grinder or plasma cutter. Many steel plates also have pre-drilled holes for mounting extra gear. Polyethylene is difficult to cut without fraying or separating the fibers. It's not recommended to alter polyethylene plates yourself, as this can weaken the integrity of the armor. Modify polyethylene plates only if the manufacturer explicitly says it won't affect protection.

Choosing the right plate cut

Body armor plates come in several cuts or shapes to fit different body types and coverage needs. Here are the most common:
Plate Cut Coverage Best For
Full cut Collarbone to navel; widest Maximum coverage and protection
Shooter's cut More shoulder/arm space Mobility with rifles and gear
SAPI cut Middle ground coverage Military compatibility and vehicles
Polyethylene and steel plates are both available in all these cuts. When comparing specific plates, make sure you're looking at the same cut so you can accurately gauge the size, weight and coverage.

How to wear it right

Proper fit is important to ensure your body armor stops bullets effectively. A plate should cover your vital organs without limiting mobility. The top of the plate should sit 1-2 inches below your collarbone, and the bottom should reach your belly button. Your plate carrier should hold the plates securely against your body. Look for a carrier with padded, adjustable shoulder straps and cummerbund. It's worth spending extra for a high-quality carrier as it's the interface between you and your armor.

Maintaining your body armor

Polyethylene and steel body armor are both durable and designed to last. However, proper care and maintenance will help your gear perform its best. Inspect your plates and carrier regularly for any cracks, bends or weak spots. Clean your carrier occasionally according to the manufacturer's tag. Store plates in a dry place away from direct sunlight and chemicals. Replace any body armor that's damaged or past its expiration date.

Training and practice

The best body armor in the world won't help you if you're not prepared to use it. Put in range time wearing your plates and carrier so you know how it feels to shoot and move. Practice basic tactics like shooting from behind cover. Consider taking a class in tactical medicine and emergency first aid. Body armor is just one part of your overall safety strategy. Combining the right gear with the right skills and mindset is the key to prevailing in any situation.

Other gear to consider

Body armor pairs well with other essential tactical gear to keep you protected from head to toe. Popular items to add to your kit include: - Ballistic helmet - Combat boots - Plate carrier accessories - Tactical gloves - Eyewear/ear protection - Extra armor plates You can find great deals on these items and more in our latest body armor sale. We have closeout prices on bundles that include a plate carrier, plates and essentials.

Trust your armor

At the end of the day, the best body armor is the set-up that you will actually wear and trust with your life. Whether you choose polyethylene or steel plates, investing in quality protection buys priceless peace of mind. We hope this guide has given you the knowledge to make an informed decision between polyethylene and steel body armor. If you still have questions, our expert team is happy to help you find the right armor for your needs and budget. Call, email or drop by our showroom anytime.
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