Viton A vs. Viton GF: What's the Difference and When Does It Matter?
Key Takeaways
- Fluorine content is what actually separates Viton A and Viton GF, with GF running around 70% against A's 66%.
- Viton GF cures with peroxide instead of bisphenol, which is what gives it stronger resistance to steam, hot water, and aggressive acids.
- Viton GF holds up to continuous heat near 450°F, about 50 degrees past what standard Viton A handles.
- Viton A covers most general sealing jobs reliably and costs less, making it the default choice unless your environment specifically calls for GF's extra resistance.
- Blaylock fabricates both grades in-house with no order minimums, so switching grades never means switching suppliers.
Fluorine content marks the real difference between Viton A and Viton GF, and that gap changes how each material handles heat, fuel, and aggressive chemicals in continuous industrial service. Viton A covers most general sealing needs reliably, while Viton GF pushes further into acids, steam, and higher sustained temperatures.
Get familiar with how their cure chemistry differs, what specs set them apart, and which one actually belongs in your next project.
What Actually Separates Viton A From Viton GF
The difference between Viton A and Viton GF comes down to fluorine content. Both share the same fluoroelastomer base, but GF's higher percentage changes how it cures, what temperatures it handles, and which chemicals it resists.
Viton A remains the standard choice for general sealing work, while Viton GF takes on the more aggressive environments that standard grades can't handle.
The Fluorine Percentage That Changes Everything
Viton A contains roughly 66% fluorine, the standard that has defined the material for decades. Viton GF pushes past that to around 70%, and that shift changes the whole compound. It cures with peroxide instead of bisphenol, holds up to continuous heat near 450°F, and resists acids, hot water, and steam that break down standard grades over time.
How Viton GF Earns Its Extra Chemical Resistance
Peroxide curing builds carbon-carbon crosslinks into the compound instead of the weaker ether bonds a bisphenol cure produces, and those bonds hold up under conditions that break standard seals down early.
Steam, hot water, and certain acids attack the crosslink structure directly, so a compound built to resist hydrolysis outlasts one that isn't.
Where Viton GF Pulls Ahead in the Field
Picture a valve packing job on a line that swings between blasting steam cycles and splashes of concentrated acid within the same shift. Standard Viton holds up for a while, then starts to soften and swell at the edges.
Swap in Viton GF and the seal keeps its shape through that same punishment because the extra fluorine and peroxide cure were built to handle it.
That's why Viton GF shows up so often in oil and gas downhole equipment, pharmaceutical sterilization lines, and chemical processing systems running solvents that standard Viton compounds can't touch.
Viton A and Viton GF Specs at a Glance
The difference between Viton A and Viton GF becomes clear once the numbers sit side by side. Fluorine content, cure type, and temperature range all shift between the two grades, and each shift changes where the material belongs on the job.
| Attribute | Viton A | Viton GF |
| Fluorine Content | 66% | 70% |
| Cure Type | Bisphenol-cured | Peroxide-cured |
| Durometer | 75 Shore A (±5) | 75 Shore A (±5) |
| Continuous Temperature | Up to 400°F | Up to 450°F |
| Chemical Resistance | Fuels, oils, hydraulic fluids, less aggressive acids | Extends to aggressive acids, steam, hot water |
Matching the Material to the Job
Cost factors into the difference between Viton A and Viton GF just as much as chemistry does. Viton A costs less and handles the vast majority of general sealing work without any performance gap, so specifying GF for a straightforward oil or fuel application adds expense without adding value.
GF earns its price where the operating environment actually demands it, in sustained heat past 400°F, acid exposure, or steam cycling. The right call comes down to matching the grade to your actual operating conditions, not defaulting to the higher-spec option out of habit.
Blaylock fabricates both grades in-house, with die cutting, CNC flash cutting, and waterjet cutting available on either material, so switching grades doesn't mean switching suppliers.
Viton A vs. Viton GF FAQs
Can Viton A and Viton GF be substituted for each other?
Substituting one for the other isn't recommended without reviewing your exact chemical and temperature exposure first. GF's added resistance exists to cover conditions that standard Viton A can't handle safely.
Is there a minimum order for Viton A or Viton GF?
No. Blaylock supplies both grades from a single square foot to full production runs, with no artificial minimums on either material.
How does Viton compare to other rubber materials like neoprene or nitrile?
Viton holds up to higher heat and more aggressive chemical exposure than general-purpose rubbers like neoprene or nitrile. For lower-temperature, less demanding jobs, those materials stay the more economical pick.
Does the published temperature range cover continuous exposure or brief spikes?
Published temperatures reflect continuous service, not short spikes. Confirm your specific exposure conditions with our team before specifying either grade for a job with temperature swings.