Top 10 Types of Rubber Parts

I see buyers lose time and money because they pick the wrong rubber part. The result is leaks, downtime, and stress.

The top 10 rubber parts are O-rings, gaskets, oil seals, hoses, bellows, bushings, grommets, wheels/rollers, impellers/diaphragms, and custom molded-overmolded parts. I explain what each does, how to choose, and how I make them reliable.

I write this as a factory owner. I focus on fit, material, hardness, temperature, and certification. I also share checks that save projects.

Are O-rings still the most common rubber part for sealing?

Leaks ruin projects. The cause is often the wrong O-ring material or size. I fix this with better material matching and tighter inspection.

Yes. O-rings remain the most used rubber seal. They are low cost, compact, and easy to install. Choose size and material by media, temperature, and pressure.

Where O-rings win and how to choose

O-rings¹ seal static flanges and dynamic pistons. I see them in pumps, valves, compressors, and HVAC dampers. The failures I review come from wrong material, wrong hardness, or poor groove design. So I start with four checks: media, temperature, pressure, motion.

Quick material guide (typical ranges)

Material	Temp Range (°C)	Key Strengths	Common Uses
NBR	-30 to +120	Oil/fuel resistance2, cost	Hydraulics, gearboxes
HNBR	-30 to +165	Heat, oil, ozone	HVAC refrigerants3, high load
EPDM	-50 to +150	Water, steam, ozone	Water lines, HVAC dampers
VMQ (Silicone)	-60 to +200	Cold/heat, inert	Food, medical, low pressure
FKM (Viton)	-20 to +200	Oil, fuels, chemicals	Engines, chemicals

✅ I measure compression set⁴.
✅ I match hardness to pressure (70 ShA is common).
✅ I check groove squeeze and stretch.

🛠️ Tip: For refrigerants and synthetic oils, HNBR works well. For hot water and steam, EPDM is safer. For aggressive fuels, FKM is a good choice.

Do flat gaskets solve flange leaks better than O-rings?

A flat gasket can seal warped flanges. But the wrong thickness or wrong shore hardness will creep and leak.

Flat gaskets work best for wide flanges and low-to-medium pressure. Pick elastomer by media and temperature. Control thickness, hardness, and bolt load.

How I spec a gasket that does not creep

Flat gaskets⁵ seal HVAC ducts, manways, and pump flanges. I confirm flange surface finish and bolt pattern. I ask for torque targets. I pick materials that resist the fluid and the temperature.

Gasket selection matrix

Factor	What I check	Why it matters
Thickness6	1–3 mm typical	Too thick creeps, too thin does not seal
Hardness7	60–75 ShA	Balances conformability and load
Media	Water, oil, acid	Drives material choice (EPDM, NBR, FKM)
Certs	FDA/WRAS/NSF8	Food/water compliance when needed

✅ I add anti-stick surfaces⁹ for easy maintenance.
✅ I use closed-cell sponge EPDM for duct doors to cut noise and leaks.
🛠️ Tip: If the flange is uneven, use softer EPDM or a foam edge strip to fill micro-gaps.

Are oil seals (lip seals) better for rotating shafts?

Shafts move. O-rings cannot handle that motion. A lip seal with a spring keeps oil in and dirt out.

Lip seals handle rotary motion. Choose a case style, garter spring, and lip material to match speed, temperature, and lubricant.

My checklist for long-life oil seals

I look at shaft hardness¹⁰ and surface finish¹¹. I verify runout and eccentricity. I choose a lip material¹² that resists the oil and temperature. I confirm spring tension for the pressure range.

Lip material guide

Lip Material	Heat	Oil/Lube	Notes
NBR	Good	Good	Cost-effective, up to ~120°C
HNBR13	Very good	Excellent	Better heat and ozone
FKM14	Excellent	Excellent	High temp and fuels
ACM/AEM15	Very good	Good	Transmissions and ATF
PTFE + Rubber case	Excellent	Excellent	High speed, low friction

✅ I polish the shaft contact zone.
✅ I add dust lips for dirty sites.
🛠️ Tip: For dry runs at startup, PTFE-lipped designs reduce burn marks.

Are rubber hoses and tubes still the backbone of fluid transfer?

A hose that cracks stops a line. A tube that swells changes the flow and causes leaks.

Yes. Rubber hoses and tubes handle vibration, bending, and thermal cycling. Match liner material to the fluid and the temperature.

How I build a hose that survives

I design layers: liner, reinforcement, cover. I match bend radius to the routing. I test burst and vacuum collapse¹⁶. I choose EPDM¹⁷ for coolant and steam, NBR for oil, and FKM for hot fuel vapor.

Hose structure snapshot

Layer	Role	Typical Materials
Liner	Fluid contact	EPDM, NBR, FKM
Reinforcement	Pressure	Textile, wire
Cover	Weather, abrasion	EPDM, CR

✅ I validate fittings with pull and pressure tests.
✅ I stamp lot and date for traceability.
🛠️ Tip: For odor-sensitive systems, peroxide-cured EPDM liners keep extractables low.

Do rubber bellows and boots really stop dust and noise?

Dust kills bearings. Splash water rusts parts. Bellows keep both away. They also cut vibration and noise.

Yes. Bellows protect joints and guideways from dust, water, and misalignment. Choose geometry, wall thickness, and rubber to match stroke and environment.

Design rules I follow for bellows

I start with the required stroke. I set the convolution count to avoid overstrain. I select EPDM for weather, CR for abrasion, and silicone for heat. I check clamping rings and groove shapes¹⁸.

Bellows design table

Factor	Target	Why
Max stroke	≤30–40% of free length	Prevents fold inversion
Wall thickness19	1.5–3.5 mm	Balance flex and life
Hardness	50–70 ShA	Flex vs. impact
Material	EPDM/CR/VMQ	Ozone, abrasion, heat

✅ I add drain weeps to avoid water pooling.
✅ I design soft end collars to seal better.
🛠️ Tip: For low-temp outdoor work, silicone or EPDM stays flexible.

Do rubber bushings and mounts solve vibration issues?

Vibration cracks brackets and loosens fasteners. A tuned bushing or mount blocks that path.

Yes. Rubber bushings and anti-vibration mounts isolate shock and noise. Tune stiffness (k) and damping to shift resonance out of the working band.

How I tune isolation

I take the disturbing frequency and the supported mass. I set the natural frequency at least √2 lower. I pick hardness by load and deflection. I choose bonding systems that do not peel.

Mount selection table

Load (kg)	Target Deflection (mm)	Suggested Hardness
10–30	2–4	45–55 ShA
30–80	3–6	55–65 ShA
80–200	4–8	65–75 ShA

✅ I run fatigue tests for 10⁵–10⁶ cycles.
✅ I add fail-safe sleeves for safety.
🛠️ Tip: Cone or sandwich mounts give more travel with a soft feel.

Are grommets and plugs just small parts—or critical ones?

A sharp panel edge can cut a cable in months. A simple grommet stops that.

Grommets, plugs, and strain reliefs protect wires and hoses at pass-throughs. Choose groove fit, panel thickness, and ozone-resistant rubber.

How I prevent chafing and leaks

I size the groove for snap-in retention. I pick EPDM for outdoor ozone. I use NBR for oil splash. I add tapered plugs for test ports.

Fit and material

Panel (mm)	Hole Ø (mm)	Groove Fit	Material
1.0–2.0	10–40	+0.2–0.5 mm	EPDM/NBR
2.0–3.0	20–60	+0.3–0.6 mm	EPDM/NBR

✅ I radius the cable through-hole to reduce cut risk.
✅ I mark sizes for fast service.
🛠️ Tip: For splash zones with diesel, use NBR or FKM inserts.

Do rubber wheels and rollers carry heavy loads without floor damage?

A hard wheel marks floors and transmits shock. Rubber changes that.

Rubber wheels and rollers add grip and shock absorption. Choose tread compound, core type, and bearing fit by load, speed, and surface.

What I change to avoid flat spots

I balance hardness and hysteresis to reduce heat. I use aluminum or steel cores for strength. I press-fit bearings with correct tolerances. I finish-grind the tread for roundness.

Wheel spec snapshot

Item	Typical Value
Tread hardness	65–75 ShA
Core	Aluminum or steel
Load per wheel	80–500 kg
Options	Non-marking, oil-resistant

✅ I run drum fatigue and drop tests.
✅ I use non-marking treads²⁰ in hospitals and schools.
🛠️ Tip: For forklifts, higher shore reduces squirm; for floor scrubbers, softer shore improves grip.

Are rubber impellers and diaphragms reliable in pumps?

A brittle impeller stalls a line. A cracked diaphragm leaks. Both failures are avoidable.

Yes. Rubber impellers and diaphragms move and meter fluids with flexibility. Choose compound for abrasion, temperature, and media. Verify bonding and hub design.

How I push service life further

For seawater impellers, I use wear-resistant rubber²¹ and strong hub bonding. For dosing diaphragms²², I pick fabric reinforcement and precise thickness. I test for hours at speed and pressure.

Selection cues

Component	Media	Suggested Material
Seawater impeller	Salt water, sand	CR/EPDM blends
Oil transfer impeller	Oils	NBR/FKM
Dosing diaphragm	Chemicals	FKM/EPDM fabric-reinforced

✅ I inspect bond lines by sectioning in trials.
✅ I track displacement and lift after endurance runs.
🛠️ Tip: For dry-start risk, add priming relief features to cut burn.

Do custom molded and overmolded rubber parts solve unique problems?

Standard parts do not always fit. Shape, load, and environment may be special.

Custom molded and rubber-to-metal overmolded parts solve the last 10% problems. They match space, stiffness, and media perfectly.

How I take a custom part from RFQ to stable production

I start with a drawing or a 3D file. I confirm the working environment. I select material by temperature, hardness, and chemical map. I choose compression, transfer, or injection molding based on geometry and volume. I plan draft and parting lines to avoid knife marks on sealing lips. I define tolerances by ISO 3302-1 class. I run DFM²³. I build soft tools for trials. I measure shrink and tune cavities. I prepare PPAP files²⁴ and control plans for series.

Process map

Step	Output
DFM + material match	Feasible design, compound spec
Tooling	3–4 week sample mold (typical)
Trials	Dimensional + functional report
Ramp	QC plan, capacity plan

✅ I keep a stable cure system for repeat shore.
✅ I use lot tracking and 100% visual checks for critical seals.
🛠️ Tip: Overmolding onto sandblasted, primed metal inserts gives strong bonds for mounts and pulleys.

Do extruded rubber profiles and sponge seals reduce air and water leaks?

A metal door leaks. A cabinet rattles. A simple extruded profile fixes both.

Yes. Extruded solid and sponge profiles fill gaps along long runs. Choose geometry, density, and adhesive backing to match surfaces and closure force.

What I check before I cut the die

I confirm the gap and the compression target. I pick closed-cell EPDM²⁵ for weather and noise. I use solid EPDM for wear points. I add tape or metal clips for fastening. I heat-joint corners to form loops.

Profile quick guide

Type	Use	Notes
D-shape sponge	Doors, HVAC	Low closing force
P-shape sponge	Hatches	Wider sealing land
Solid strip26	Wear points	Higher durability
Edge trim	Panels	Protect and seal edges

✅ I test IP rating with pressure and immersion checks.
✅ I color-mark hardness for quick ID.
🛠️ Tip: Heat-vulcanized corners seal better than glued joints.

How do I pick materials and hardness across all these parts?

Wrong material is the #1 root cause I see. It is also easy to fix with a simple matrix.

I map media, temperature, motion, and certification to a shortlist. I then set hardness by load and sealing force.

Universal selection table

Scenario	Material	Hardness (ShA)	Notes
Hot water/steam	EPDM	60–75	Great ozone/weather resistance27
Oils and fuels	NBR/HNBR/FKM	70–80	HNBR for high heat; FKM for fuels
Low temp flex	Silicone (VMQ)	50–70	Food/medical options
Abrasion	CR/NBR blends	65–80	Wheels, sleeves
Chemicals	FKM/EPDM	60–75	Check compatibility chart

✅ I verify compression set at service temperature.
✅ I check regulatory needs (FDA, WRAS, NSF, RoHS²⁸).
🛠️ Tip: Start with 70 ShA for seals. Adjust up for load, down for misalignment.

Conclusion

I select the right rubber part by mapping media, temperature, motion, load, and certs. I build in quality, then I test.

Need help with a spec or a quote?
I can review drawings, materials, and tolerances. I also provide samples fast.

• Visit: Julong Rubber — Custom Rubber Parts
• Email: info@rubberandseal.com
• Or reach out to us directly via WhatsApp:
  

---