Daily, we receive calls from Engineers, Maintenance Personnel and mechanics about what sheet gasket material is best for their application. With so many choices, it's understandable as to why after hours of work designing, repairing or rebuilding one would hesitate to select which material to choose. After all, the gasket is often the weak link in the equipment, and the first thing to fail. Millions of oil dotted driveways prove that point.
So where to begin? Well, the first thing to consider is just how difficult is the application? If it's an easy application, just about any material will work (sealing low pressure air or water for example). Next we suggest considering how important the gasket maintaing a seal is to you. Often there is a trade off between reliability and cost. We can supply a gasket that rarely needs replacing, or one that wll last the preventaive maintenance cycle of the equipment. Generally it is far more cost effective to use a higher quality material than to suffer the cost of down time, labor and replacement costs. However some OEM (original equipment manufactures) are looking for the least expensive gasket that will do the job. We can work with you either way.
The key questions you need to ask are:
What temperature will the gasket see?
Does the temperature cycle up and down?
What are we sealing? (oil, gas, water, chemicals, food, etc?)
Is there any pressure, and if so how much?
Does the pressure cycle?
What is the application or type of equipment the gasket is in?
Does the Gasket see abrasives?
Is there a specification the Gasket Material must meet? FDA, ANSI, NSF, MIL, WRAS, UL,Etc.
Is the application static or dynamic? If it is dynamic, what speed is it seeing?
Each of the above questions leads us to a material that meets the requirements for an effective long term sealing material.. Below is a list of gasket material specification catagorized by the type of material.
Each customer often have their own preferred/specified brand. Manufacturers product numbers are always helpful. We can provide most brands as desired, or assit engineering/maintenance or purchasing by recommending the best known equal brand. Our focus is to provide the best available technology resulting in high quality seals. We also offer "Generic products", for those on a budget.
Flexible graphite is an exceptional material that is effective in high temperature applications such as exhaust gaskets and steam. Graphite is compatible with most chemicals and has a 0-14 ph range. Every major refinery, power generation facility and chemical plant relies on this unique material to meet the sealability standards required by governments.Good for temperature 850 F +. The less oxygen present, the higher the temperature rating (up to 5,400 F) for flexible graphite.
Deciding on compresed non-asbestos sheet is a good first step.Like cars, non-asbestos is made in both high end and low cost models. The first thing you want to be sure of is "Branded material is always better" Especially today, there is an increased amount of cheap knock off brands comming into the market.
Protect your equipment and stick to name brands or AS&P recommended styles.
Mica is a natural mineral that holds up to heat. Beacuse it will withstand up to 1,652 F (900 C), it's a great solution in oxydizing atmosphers where flexible graphite will carbonize to powder and loose it's sealing capability. Like Flexible Graphite it is available with reinforcing metal laminates of stainless steel foil or tang. The purpose is to imporve handleability. Most comonly you will find two basic forms: Phlogpite and Muscovite. Both are used in gasket materials, and in somecases blended. We offer both hard and soft versions to fit your application. In some cases a soft material will assist in conforming to irregular surfaces as a gasket should. In other applications a harder more pressure resistant material is desired.
We offer FMI, Durlon and Thermoseal as well as unbranded styles.
Paper Gaskets got their name because they are made on a paper machine that takes pulp and turns it into a sheet. The pulp process allows gasket manufacturers to convert many types of materials into a sheet without the cost of blending it with rubber. Non-asbestos gasket materials are generally made in a batch process that blends fibers with rubber and is compresed on a rubber calander process.. Today the pulp process used in "beater add" gasket materials reduces the cost of a batch process items. Gasket materials made a pulp or beater add process will not handle as much pressure as compressed non-asbestos sheets, but in applications like automotive gaskets they are often used due to their low cost.
Silicone is a soft and conformable material that will withstand temperatures to 450 F. It also has excellent resistance to ozone, which is why it is used to caulk window frames on houses. One consideration with silicone is that it does not like oils. It's not a high pressure material either.
But if your application is water, air, or exposed to ozone, it's hard to beat.
A common misconception is that all rubbers of the same type are the same. The truth is you would be hard pressed to find two that are identical. The reason for this is all rubbers are compounds. Compounds are blends. So the Nitrile rubber you bought may have a dash of EPDM added to it to improve the ozone resistance. Your EPDM may have Buna-N in it to imporve oil resistance. Of course brand X's EPDM may have more nitrile in it than brand Y's. As a result it is more perilous to try to save a buck by shopping rubber sources. Make sure quality is a priority with your supplier.
|Carboxylated Nitrile - (XNBR)
|Hydrogenated Nitrile - (HNBR)
|Natural Gum Rubber
Ph: 714-593-9780 Fax: 714-593-9701
Call American Seal & Packing for your gasket material requirements. .