VITON, EPDM or NBR? Why the seals decide what your sprayer can handle
Two sprayers can look the same from the outside and handle completely different chemicals. The difference is inside: the rubber seals and O rings in the pump, valve and trigger. Get the seal material right and a sprayer lasts for years. Get it wrong and it can leak within days.
Here's what each seal type is for.
The three main seal types
This table shows what sprayers fitted with each seal type are sold for. Always check the sprayer itself, because valves and nozzles matter too.
| Seal | Sprayers with it suit | Not for |
|---|---|---|
| VITON or FKM | Petroleum solvents and oils: brake cleaner, degreaser, diesel, kerosene, turps, tyre shine, formwork oil, sealers, xylene | Alkaline chemicals, acetone, and acids unless the sprayer is sold as acid resistant |
| EPDM | Alkaline chemicals and some aggressive solvents: caustic soda, glycol brake fluid, methanol, acetone | Acids, oils and petroleum solvents |
| NBR | Light duty use: diesel, oils and light solvents | Acids, alkaline chemicals, acetone |
For any chemical not in this table, check with us before use.
VITON and FKM
FKM is a family of tough synthetic rubbers, and VITON is the best known name for it. These seals stand up to petroleum solvents and oils, so they're the standard choice for workshop sprayers used with brake cleaner and degreaser. Read more in our brake cleaner spray bottle guide.
Some sprayers use a heavier duty grade, such as FKM80, for harsher workshop solvents.
VITON seals are also used in acid resistant sprayers. Those sprayers add other acid resistant parts too, such as an acid trigger valve and a PVDF nozzle. So a solvent sprayer with VITON seals is still not an acid sprayer.
EPDM
EPDM seals suit alkaline chemicals such as caustic soda, plus glycol brake fluid, methanol and acetone. They're common in cleaning industry sprayers and foam sprayers.
EPDM is the wrong choice for oils and petroleum solvents. Brake cleaner in an EPDM sprayer will damage the seals.
NBR
NBR (nitrile) seals are found on light duty sprayers. They suit diesel, oils and light solvents. They are not made for acids, alkaline chemicals or acetone.
Signs your seals are wrong or worn
- The trigger or pump weeps or drips
- The sprayer won't build or hold pressure
- Seals look swollen, soft, sticky or cracked
- The spray pattern turns into a dribble
If the seals failed quickly, the chemical probably doesn't suit them. Switch to a sprayer made for that chemical, because new seals of the same type will fail again. If they lasted a long time, they've likely just worn out, and a new seal kit usually brings the sprayer back to life.
Never swap acid and alkaline seal kits
Acid and alkaline sprayers can look alike but use different seal kits. Fit an alkaline kit to an acid sprayer, or the other way round, and the seals will fail. Always fit the kit made for your exact sprayer model.
Choosing a seal kit
- Find the model of your sprayer. It's usually on the label or the tank.
- Check which chemical family the sprayer was built for: solvent, acid, alkaline or another.
- Choose the seal kit made for that model and chemical.
- Not sure? Send us a photo of the sprayer and we'll help you match it.
Make seals last longer
Release the pressure after every use. Rinse the sprayer and store it out of the sun. Keep one sprayer for each chemical family. Our guide on how to use and look after a pump up sprayer has more tips.
Questions
What is the difference between EPDM and VITON?
VITON (FKM) seals suit petroleum solvents and oils. EPDM seals suit alkaline chemicals and some aggressive solvents such as acetone. A solvent sprayer isn't made for alkaline chemicals or acetone, and an EPDM sprayer isn't made for oils or petroleum solvents.
Are VITON seals acid resistant?
VITON seals are used in acid resistant sprayers, but those sprayers also have acid resistant valves and nozzles. A solvent sprayer with VITON seals is not made for acid.
Can I upgrade my sprayer by fitting different seals?
Only fit the seal kit made for your sprayer model. Other parts of the sprayer may not suit a different chemical.
Which seals do I need for bleach?
Use a sprayer sold as bleach resistant. See our chemical guide.