Compare the construction before the material label
Dense virgin PTFE, filled PTFE and expanded PTFE are different materials for procurement purposes. Graphite sheet can be unreinforced or contain metal foil, tanged metal or mesh. Those distinctions affect handling, geometry and the selected joint construction.
| Family | Construction to identify | Procurement check |
|---|---|---|
| Virgin PTFE | Dense sheet or cut gasket | Grade, thickness, creep/loading requirements. |
| Modified or filled PTFE | Named formulation | Filler and grade-specific fluid compatibility. |
| Expanded PTFE | Expanded sheet or strip | Grade, thickness and installation loading. |
| Flexible graphite | Plain sheet or cut gasket | Purity/grade and handling requirements. |
| Reinforced graphite | Metal insert plus graphite | Insert form, alloy and finished thickness. |
Which fluid and operating details are needed?
Identify the actual medium, concentration where relevant, normal and design conditions, and cleaning fluids. A pH range alone is not a complete chemical compatibility assessment. Strong oxidizing conditions are particularly important to identify when evaluating graphite.
Keep temperature and pressure with the fluid and joint details. Do not combine a family-level maximum temperature with another product’s pressure value. Ask for data applicable to the selected grade and equipment specification.
How does the flange affect the choice?
Available bolt load, flange material and geometry determine how a gasket can be seated. A fragile or lined flange requires a different review from a steel pressure flange. Thickness and reinforcement should be part of that review rather than chosen for convenience.
For a replacement, record the existing gasket construction and determine why a change is being considered. Changing to a thicker gasket or a softer material does not automatically resolve a leakage problem. Consult the equipment and installation requirements before substituting.
What should the quotation compare?
| Keep identical | Identify separately |
|---|---|
| Drawing and required dimensions | Material formulation and reinforcement. |
| Quantity and destination | Thickness and tolerance. |
| Operating duty | Grade-specific limitations. |
| Inspection requirements | Available technical data and reports. |
Compare PTFE gaskets, expanded PTFE gaskets and graphite gaskets by their actual construction. A lower price for another grade is a different product offer, not necessarily a matched alternative.
What documents support the decision?
A grade-specific data sheet should identify the material and test conditions. Project-required material reports or approvals need the corresponding product scope. A statement about a supplier’s quality system does not approve every gasket for food, oxygen or other special service.
Use a dimensioned gasket sketch together with the material specification when the part is not standard. Mark open fields in the RFQ so the quotation does not silently assume them.
Product construction and material details
White PTFE sheet stock Graphite gasket filler tape roll
Frequently asked questions
Is expanded PTFE the same as virgin PTFE sheet?
No. Expanded PTFE has a different structure from dense molded or skived PTFE sheet. Compare the selected grade, thickness and loading requirements.
Is graphite suitable for every chemical medium?
No. Chemical compatibility is condition-dependent, and oxidizing media require particular attention. Use grade-specific data for the actual medium and conditions.
Does metal reinforcement change the graphite gasket?
Yes. Reinforcement changes the construction and must be identified by form and alloy. Plain graphite and reinforced graphite are separate purchase descriptions.
Related products
PTFE Gaskets
PTFE cut gaskets for joints where chemical compatibility is central to selection.
- Product form
- Virgin PTFE; filled PTFE; modified PTFE
- Ordering dimensions
- Drawing
A standard reference identifies dimensions or design requirements; it does not certify every material for the service.
Graphite Gaskets
Cut graphite gaskets for flat sealing joints.
- Product form
- Unreinforced graphite; metal-foil and metal-mesh reinforcement
- Ordering dimensions
- Drawing
A standard reference identifies dimensions or design requirements; it does not certify every material for the service.
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Related reading
How to Measure a Gasket for a Replacement
Record the geometry, units and material as separate parts of the replacement specification. A used gasket can be compressed or distorted, so compare sample measurements with the flange or equipment drawing wherever possible.
Read more →Industrial Gasket RFQ Checklist
A complete gasket RFQ identifies geometry, construction, material, quantity and delivery scope. Keep each size on its own line and mark unresolved fields so the supplier does not need to assume a grade, ring style or inspection requirement.
Read more →Product information
Review the product construction and ordering details before submitting a quotation request.
View product specifications ↗