Bonded sealing washers create a seal that provides a greater degree of corrosion protection than conventional washers do. … Sealing washers help seal joints, prevent leakage and provide cushioning under the head of the bolt or nut. Bonded washers are used in combination with a gasket.

How do bonded seals work?

A bonded seal, a metal washer with a vulcanized rubber insert for use in high pressure applications where other means of sealing are unsuitable. The flexing action of the lips under pressure provides a positive and leak proof seal against a wide range of fluids.

What are Dowty washers used for?

Often used as bolt seals in hydraulic equipment, today bonded seals (commonly known as Dowty Seals or Dowty Washers) are finding usage in many and varied applications throughout industry.

What are EPDM washers used for?

EPDM (ethylene propylene diene monomer) : A popular Elastomer for outdoor Applications where weather and water resistance is required. EPDM offers a Superior resistance to Ozone, UV and sunlight. It also has a good resistance to steam and brake fluid.

What is an EPDM washer?

Ethylene Propylene Diene Terpolymer or more commonly known as EPDM rubber is a specialised based material and is particularly suited to a wide range of sealing applications. … There are many other advantages to using EPDM rubber washers, other than just for sealing purposes.

Are Dowty washers reusable?

Dowty Washers are comprised of a flanged nitrile (NBR) rubber insert bonded to the inside of a thick steel washer. … The washer prevents the seal from getting crushed or extruding outwards, which makes them re-usable.

How do sealing washers work?

Inside diameter of rubber washer is designed to seal tightly to screw. When installed in a sealing application, the materials in Sealing Washers compress against either a flexible or an inflexible surface to permanently seal in or seal out any operating environment, whether natural or industrial.

Is EPDM the same as nitrile?

Two common synthetic rubber compounds are known as EPDM and nitrile rubber. … The main difference between NBR and EPDM is that NBR is a non-aromatic polymer compound while EPDM is an aromatic polymer. NBR and EPDM are two types of rubber materials.

Which is better Nitrile or EPDM?

EPDM vs. NBR: Nitrile butadiene rubber (NBR) stands alone as the most oil- and fuel-resistant elastomer. It is also known for maintaining its stability in low temperatures. … On the other hand, EPDM is a UV-resistant rubber that has a great tensile strength and is moderately resistant to abrasions.

Is EPDM rubber fuel resistant?

ElastomerOil ResistanceFuel ResistanceEPDMPoorPoorNatural RubberPoorPoorSBRPoorPoor

Article first time published on

Can Dowty Seals be reused?

Reusable when remaking joints. The Dowty Bonded Seal is available in the full range of sizes for low octane fuels, diesel oil, etc., suitable for temperature ranges of -20°F to +240°F (-29°C to +120°C).

What are lock washers?

Lock washers are designed to be tightened to a required torque beneath an ordinary fastener. They exert a spring tension that keeps the fastener from vibrating loose. They are often attached to the nut side of the fastener.

What is an elastomeric seal?

An elastomer gasket or elastomeric gasket is a gasket that is made from a silicone elastomer based material, such as silicone rubber, silicone foam, silicone sponge, PORON® cellular urethane and fluorosilicone. Silicone elastomers are synthetic rubber materials that provide the material base for many gaskets.

How long does EPDM last?

EPDM roof membranes remain stable over time and can have a life expectancy of over 50 years. ** Made from synthetic rubber, EPDM roofing membranes have two primary ingredients, ethylene and propylene, which are derived from oil and natural gas.

What is difference between EPDM and neoprene?

EPDM functions better in higher temperatures, with a maximum of 300-350 degrees F, while neoprene handles only up to 225 degrees F. It’s also steam resistant and more ozone resistant. However, unlike neoprene, EPDM swells if put in contact with petroleum oil, fluid, or solvent.

How long do neoprene washers last?

They also have a slightly larger and slightly domed metal washer stacked on top which creates an umbrella for the neoprene that guards it against the UV rays that cause cracking. We are seeing screws that at this point can live roughly 50 years if not longer without failed washers.

Why are sealing washers used?

These sealing washers are used in combination with standard screws and bolts to seal out water, oil, dust, solvents and other materials or contaminants.

Are neoprene washers waterproof?

The neoprene coating also provides effective protection against corrosion, a common problem in these applications. Neoprene washers are used with polycarbonate panels, most often on roofs and in windows as a replacement for glass. … They are only part of a system that ensures a polycarbonate roof or window is waterproof.

Where are Dowty washers used?

A metal washer bonded to rubber, bonded washers (aka Dowty washers) are used to prevent leakage of media through fasteners of hydraulic fittings, pipe join flanges and valve bodies. A bonded washer consists of a flat metal ring with rubber bonded to the internal diameter that is wider than the metal washer.

What does EPDM stand for?

EPDM stands for ethylene propylene diene monomer, which is a bit of a mouthful, so it’s commonly shortened to EPDM or EPDM rubber. EPDM gets its name from the chemicals (monomers) that are mixed together in various proportions to form it. These are ethylene, propylene and diene.

What is a disadvantage of neoprene?

The primary disadvantage of neoprene is its cost. Several other materials offer similar characteristics at a lower price. Neoprene also offers poor resistance to strong oxidising acids, esters, ketone and certain hydrocarbons. Other rubber materials deliver superior oil resistance.

What is O-ring material?

O-rings are mechanical gaskets with a round cross section. They are used to prevent gas and fluid leaks in static and dynamic applications and are manufactured from various types of elastomers. Some of the common types of O-ring materials include PTFE, Nitrile (Buna), Neoprene, EPDM Rubber and Fluorocarbon (Viton).

Is nitrile better than rubber?

Nitrile rubber is more resistant than natural rubber to oils and acids, with superior strength, but does have less flexibility. Nitrile gloves are therefore more puncture-resistant than natural rubber gloves, especially if the latter are degraded by exposure to chemicals or ozone.

Is nitrile rubber expensive?

The advanced formulas of Unigloves’ nitrile glove ranges make them comfortable and suited to longer wear; however, they are often a more expensive option than latex or vinyl gloves.

Are nitrile O rings better?

You’ll find nitrile o rings used in many applications, including where oil resistance is needed or where low temperature functionality is required. … This material has an excellent tolerance for high temperatures, resistance to oils, fuels and hydraulic fluids as well as aromatics and solvents.

Is EPDM the same as Teflon?

EPDM is softer and makes a better sealing material (conforms better to rough surface finishes). Teflon is stiffer and slicker, which might hold up better in a dynamic or abrasive application. Both could care less about sea water from a chemical attack/corrosion standpoint.

At what temperature does EPDM melt?

Ethylene-Propylene-Diene-Rubber-Mixture (EPDM) The melting above the glass transition (peak temperature at 31.4°C) is typical for the behavior of a sequence-type EPDM. The further endothermal effects (at 98.6°C and 110°C) are due to the evaporation of processing agents.

Is EPDM good for chlorine?

EPDM and Butyl liners have a proven track record of long service life but as organic materials – chlorine will react with them – as well as with the chemicals in the water. Chlorine, when correctly dosed in water, will always react first to the materials in contact with the water, such as a liner.

Are lock washers necessary?

Lock washers are needed when the fastener assembly is subject to vibration or wherever back off is considered an issue. When should I use washers with bolts? Always use a washer between the installation material and the nut.

Do I need a flat washer with a lock washer?

A lock washer is designed to press into the surface of the nut and whatever is being fastened. Flat washers spread out the load of the tension to prevent pull through or bending whats being fastened, but makes lock washers useless.

What goes first lock washer or washer?

When used correctly, a lock washer will hold the nut or other threaded fastener in place. To help it accomplish this, put the lock washer on first, below the fastener. If your project calls for other washers or hardware elements, they should go on before the lock washer so that it can hold them in place.