EZ Coating surface treatment solutions outperform Teflon™ PTFE coating systems for O-ring coatings in several key areas.
In today’s blog, our experts answer frequently asked questions about O-ring coatings.
What substances are best for sealing O-rings?
O-rings are made from different types of elastomers that have enough flexibility to work with moving parts and have the sealing capabilities to prevent fluid leaks.
Your company has certain standards that O-rings must meet in terms of flexibility, durability, and resistance to chemicals and temperatures.
You must plan accordingly with your O-ring purchases because they must work in the specific environment you need them to. Every type of standard O-ring has a temperature limit.
Make sure your O-ring works within its temperature range based on the material it’s made out of:
- Nitrile has a temperature range from -50 C to 120 C
- Hydrogenated nitrile ranges from -45 C to 150 C
- Polyacrylate goes from -25 C to 175 C
- Ethylene-propylene has a range anywhere from -50 C to 135 C
- Chloroprene ranges between -40 C to 120 C
- Butyl (petroleum compound) goes anywhere from -55 C to 205 C
- Fluorosilicone ranges from -60 C to 205 C
- Fluorocarbon has a range from -25 C to 205 C
The O-ring material with the greatest temperature range is fluorosilicone, one of the most durable O-ring materials available. It’s a common application in the aerospace industry because it operates at such a low temperature.
When you consider low-earth orbit is about 10 degrees Celsius and temperatures can shift from one extreme to the other depending on whether a spacecraft is in the shade or sun, O-rings must be adaptable and capable in wide temperature swings.
Can O-ring coatings increase their temperature ranges?
Yes, which is why we have an O-ring coating that works better than PTFE. The temperature range of PTFE is -185 to 232 C, which outpaces ordinary O-rings without coatings.
How do I choose the right O-rings for my equipment?
Consider many factors when choosing O-rings for your equipment.
Think about:
Operating conditions, such as at sea, in the air, at construction sites, or in a tightly controlled climate within a factory building.
Chemical compatibility when working with VOCs, hydrocarbons, food, alcohols, esters, and more.
Sealing pressure based on light or hard seals as well as the method of sealing.
Temperature, particularly when operating in constant heat or constant cold.
Durometer, the hardness of the rubber. Some applications of O-rings can’t be very brittle when they need flexibility.
Size, particularly the ratio of inside and outside diameters. Large O-rings may need special considerations because they usually must remain relatively still and without transverse movements relative to the two parts they are sealing.
Cost, because you need to weigh the costs of more expensive materials versus the benefits.
Special conditions may also call for resistance to abrasion, wear, tear, ozone, and electricity.
If you’re looking to change O-rings or add coatings, always perform field tests first.
How do I make O-rings seal better?
Use a lubricant on the O-rings to make them seal better. Make sure the lubricant is appropriate for your application.
Remember, the lubricants are technically and chemically different from actual O-ring coatings, although O-ring coatings are considered lubricants.
What types of O-ring lubricants are there?
Popular choices for O-ring lubricants include:
- Petroleum distillates made from hydrocarbons.
- Solvents such as benzene.
- Soap with its surfactant properties.
- Water because it’s completely inert.
- Polymers that are also chemically inert and also have a greater temperature range.
- Ester-based grease products that go on thick.
Even when you use a lubricant, having an O-ring coating is still a good idea because it can make the lubricant more effective.
What types of O-ring lubricants are there?
There are three main classes of O-ring lubricants.
Internal lubricants are mixed into the elastomer before it’s molded. The internal lubricant is mixed and dispersed evenly throughout the O-ring. The coefficient of fiction is automatically lowered throughout the entire O-ring due to the properties inherent in it. Some measure of the internal lubricant exists on the surface of the O-ring where it’s needed the most.
You can still add coatings to O-rings even if they have internal lubricants.
Temporary external lubricants are liquids applied to the surface of the molded O-ring. If you want to remove the temporary external lubricant, you may need to do so with water or solvents. These substances reduce the risk of pinch, cutting, and abrasion during the assembly process.
Semi-permanent lubricant coatings, sometimes water-based, can be applied to O-rings by spraying, dipping, or vapor disposition. Sometimes you can bake these coatings into the O-rings, and to remove them they have to be worn away.
What coatings can I use on O-rings?
PTFE (Teflon) is the most common one. EZ Coating’s product performs better than that.
How do I apply O-ring coatings?
The most common application methods include spraying, dipping, and vapor disposition.
Under what circumstances would I want coated O-rings?
When you want better performance for your O-rings.
Does your equipment not perform as well as you’d like? Do your O-rings continually slip, erode or succumb to the elements? Do they not live up to expectations?
What factors do O-ring coatings need to perform in order to deliver specified results?
O-ring coatings help your O-rings perform better thanks to improved:
1. Coefficient of friction
2. Abrasion resistance
3. Chemical resistance
4. Color brightness
5. Painting/printability
What company can supply me with the best O-ring coatings?
EZ Coating can deliver O-ring coatings that beat PTFE (Teflon) in several important factors.
Contact us for more information or if you need a test sample.
