Specifications

Complete specifications for PTFE stirring plugs. Items marked Customizable available upon request.

Joint Size (#)	Top Diameter (mm)	Bottom Diameter (mm)	Height (mm)	Bore (mm)	O-Ring
14	14	11	42	8	PTFE-coated
19	19	16	42	8	PTFE-coated
24	24	21	48	8	PTFE-coated
29	29	26	48	8	PTFE-coated
34	34	31	48	8	PTFE-coated
40	40	36	51	8	PTFE-coated
45	45	41	52	8	PTFE-coated
50	50	46	60	8	PTFE-coated
60	60	55	65	8	PTFE-coated

Custom bore sizes available upon request.

📌 Customization Options:
• Bore Size: Standard 8mm — 6mm, 10mm, 12mm available upon request
• O-Ring Material: PTFE-coated (standard) / FFKM / Silicone
• Custom Joint Sizes: Non-standard sizes available
• Custom specifications available upon request — consult our technical team

Product Description

I. Overview

The PTFE stirring plug is precision-machined from high-purity PTFE resin for use with standard joint glassware. A PTFE-coated O-ring is integrated into the plug body to provide reliable dynamic sealing around the stirring shaft while allowing free rotation.

Unlike standard stoppers, the stirring plug allows a stirring shaft to pass through while maintaining a gas-tight seal — an essential component for stirred reaction systems. PTFE's chemical inertness ensures compatibility with strong acids (including HF), strong alkalis, aqua regia, and all organic solvents.

Available in 14#, 19#, 24#, 29#, 34#, 40#, 45#, 50#, and 60# standard joint sizes — compatible with all standard joint flasks, tubes, and reactors. Widely used in chemical synthesis, pharmaceutical R&D, and materials science.

II. Core Performance Parameters

Purity: High-purity PTFE with ultra-low metal leaching (Pb, U < 0.01ppb)
Operating Temperature: -196℃ ~ 260℃
Sealing: PTFE-coated O-ring (standard)
Chemical Resistance: Resistant to HF, aqua regia, concentrated H₂SO₄, HNO₃, strong alkalis, organic solvents
Joint Sizes: 14# / 19# / 24# / 29# / 34# / 40# / 45# / 50# / 60#
Standard Bore: 8mm (fits standard stirring shafts)

III. Material & Workmanship

Manufactured from imported high-purity PTFE resin using precision machining in cleanroom environments — ensuring dimensional accuracy, smooth surfaces, and burr-free finish. The O-ring features a PTFE coating that combines PTFE's chemical inertness with elastomeric sealing performance.

The plug's taper precisely matches standard joint specifications (1:10 taper) for tight, leak-free fit. The bore is accurately sized for smooth shaft insertion with reliable sealing.

Each product undergoes rigorous visual and dimensional inspection to ensure precision and surface quality.

Applications

Typical Applications

Stirred Reaction Sealing

Dynamic sealing for stirred reactions — prevents gas leaks and contamination

Inert Gas Protection

Maintains oxygen/moisture-free environments with inert gas flow

Vacuum Reactions

Sealed stirring under vacuum conditions

Reflux Reactions

Sealing the stirrer entry in reflux apparatus — prevents solvent loss

Corrosive Reactions

Safe stirring in strong acid/base environments

Industries

Pharmaceutical Drug synthesis, API development
Chemistry Labs Organic synthesis, polymerization, catalysis
Materials Science Nanomaterial synthesis, crystal growth
Semiconductor Chemical synthesis, wet processing
Research General stirred reaction operations

Chemical	PTFE Compatibility	Recommended Temperature	Notes
Hydrofluoric Acid (HF)	✅ Fully Compatible	≤ 250℃	PTFE is the only reliable material
Aqua Regia	✅ Fully Compatible	≤ 200℃	Avoid extreme conditions
Conc. H₂SO₄ (98%)	✅ Fully Compatible	≤ 250℃	Handle with care when heating
Conc. HNO₃ (65%)	✅ Fully Compatible	≤ 250℃	Store away from light
NaOH (50%)	✅ Fully Compatible	≤ 200℃	Safe handling required for concentrated alkalis
Organic Solvents	✅ Fully Compatible	≤ Solvent BP	Ensure ventilation and fire safety

Selection Guide

I. By Vessel Joint Size

Vessel Joint	Recommended Plug	Typical Vessel
14#	14#	Small tubes, micro flasks
19#	19#	Small flasks, tubes
24#	24#	Standard flasks (most common)
29#	29#	Standard flasks
34# ~ 60#	Matching size	Large reactors, vessels

II. By Stirring Shaft Diameter

Standard shaft (8mm): Standard 8mm bore
Thin shaft (6mm): Custom 6mm bore available
Thick shaft (10mm/12mm): Custom 10mm or 12mm bore available

III. O-Ring Material Selection

PTFE-coated (standard): Chemically inert — suitable for most corrosive environments
FFKM (upgrade): Higher temperature resistance and elasticity — for extreme conditions
Silicone: Good elasticity — for mild conditions

💡 Selection Tip: 24# is the most common size — suitable for most standard laboratory flasks. Choose this as your default.
The plug joint size must exactly match the vessel joint — do not mix sizes.
For high vacuum or high pressure applications, choose the FFKM O-ring upgrade for more reliable sealing.
After installation, the stirring shaft should rotate smoothly with no binding or excessive play.

Operation & Maintenance

User Guide

Standard operating guidelines for PTFE stirring plugs. Proper use and maintenance ensure sealing performance and product longevity.

I. Pre-use Preparation

Inspect the plug and O-ring for damage or deformation
Check the joint surface for smoothness — no scratches
Clean with ultrapure water or appropriate solvent
Confirm plug size matches the vessel joint

II. Installation

Insert the stirring shaft through the plug bore
Gently insert the plug into the vessel joint — ensure proper taper fit
Adjust shaft position — ensure the stirrer blade does not contact vessel walls
Hand-rotate the shaft to confirm smooth operation before starting the motor

III. Seal Check

After installation, check sealing by applying slight pressure or vacuum
If leaks are detected, gently tighten the plug or replace the O-ring
Periodically inspect the O-ring during prolonged use

IV. Cleaning & Maintenance

Clean with ultrapure water or appropriate solvent after use — PTFE's non-stick surface makes cleaning easy
Stubborn residues may be soaked in dilute nitric acid
The O-ring can be removed for cleaning or replacement
Never use hard brushes or abrasives — may scratch the joint surface

V. Important Notes

PTFE is relatively soft — avoid dropping or impact with hard objects
Do not exceed rated temperature during prolonged use
Avoid contact with molten alkali metals (Na, K) and elemental fluorine
O-rings are consumable — inspect and replace regularly

💡 From a Seasoned Lab Technician: "Apply grease — turn smoothly" — A thin layer of vacuum grease or PTFE lubricant on the joint surface improves sealing and makes insertion/removal easier.
Do not over-tighten — insert until moderate resistance is felt. Over-tightening may damage the joint or cause seizing.
The O-ring is the critical sealing component — inspect it before each use. Replace if cracked, deformed, or aged.
The shaft should fit snugly with free rotation — no gaps, no binding.

Care & Notes

Show care & notes

⚠️ Safety & Compliance Checklist

Pressure Safety

Confirm plug is securely installed before pressurizing

Chemical Safety

Corrosive chemical operations must be performed in a fume hood

PPE

Safety goggles, lab coat, acid/alkali resistant gloves required

Compliance

All operations should follow laboratory safety guidelines

PTFE Stirring Plug

Specifications

Product Description

I. Overview

II. Core Performance Parameters

III. Material & Workmanship

Applications

Stirred Reaction Sealing

Inert Gas Protection

Vacuum Reactions

Reflux Reactions

Corrosive Reactions

Selection Guide

I. By Vessel Joint Size

II. By Stirring Shaft Diameter

III. O-Ring Material Selection

User Guide

I. Pre-use Preparation

II. Installation

III. Seal Check

IV. Cleaning & Maintenance

V. Important Notes

Care & Notes

Pressure Safety

Chemical Safety

PPE

Compliance

Need PTFE Stirring Plugs?

PTFE Stirring Plug

Specifications

Product Description

I. Overview

II. Core Performance Parameters

III. Material & Workmanship

Applications

Stirred Reaction Sealing

Inert Gas Protection

Vacuum Reactions

Reflux Reactions

Corrosive Reactions

Selection Guide

I. By Vessel Joint Size

II. By Stirring Shaft Diameter

III. O-Ring Material Selection

User Guide

I. Pre-use Preparation

II. Installation

III. Seal Check

IV. Cleaning & Maintenance

V. Important Notes

Care & Notes

Pressure Safety

Chemical Safety

PPE

Compliance

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