• Transparent Magnaflux Centrifuge Tube 14A for measuring magnetic particle concentration in baths.
  • Metal stand holding Magnaflux Centrifuge Tube 14A, demonstrating its use in monitoring magnetic particle baths.
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Magnaflux

Magnaflux Centrifuge Tube 14A, 14AM, 20B

Magnaflux Centrifuge Tube 14A, 14AM, 20B

SKU: 8493

Stock Status: In stock
$284.00
$284.00
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Magnaflux 8493 Centrifuge Tube for Fluorescent MPI Bath Monitoring

The Magnaflux 8493 is a 100 ml ASTM pear-shaped centrifuge tube used to monitor the bath concentration and contamination level of magnetic particles in Magnaglo 14A, 14AM, and 20B fluorescent magnetic particle baths. Graduated from 0 to 1.0 ml in 0.05 ml increments, the 8493 provides the precise readings needed to maintain consistent bath strength and reliable inspection results.

Note: Centrifuge tube only — stand must be purchased separately.

Why Bath Concentration Monitoring Matters

The amount of magnetic particles per gallon of fluid in the inspection bath is called its concentration or bath strength. Maintaining the correct concentration is critical:

  • Too low: Weak or absent indications — defects may go undetected
  • Too high: Heavy background buildup masks indications — fine defects become invisible
  • Correct range: Consistent, reliable indications for all defect types

Bath strength should be checked at least once per day, after thorough mixing and agitation of the entire bath. The gravity settling method using an ASTM pear-shaped centrifuge tube is the most widely used and accepted technique.

Pro NDT Tip

The 60/30 Settling Rule: After drawing your sample, allow it to settle before reading concentration — 60 minutes for oil-based baths (Carrier II), 30 minutes for water-based baths. Target concentration for 14A and 14AM is typically 0.15–0.25 ml/100 ml. For 20B water baths, follow your procedure specification. Always agitate the bath for at least 15 minutes before sampling to ensure particles are fully suspended.

Compatible Magnetic Particles

  • Magnaflux 14A — High-sensitivity fluorescent powder concentrate for oil or water baths
  • Magnaflux 14AM — Ready-to-use oil-based fluorescent MPI suspension
  • Magnaflux 20B — Water-based fluorescent MPI premix with built-in wetting agents

Specifications

Magnaflux 8493 Centrifuge Tube Specifications
Property Specification
Part Number 8493
Volume 100 ml
Graduation Range 0 – 1.0 ml
Graduation Increment 0.05 ml
Shape ASTM pear-shaped
Compatible Particles Magnaglo 14A, 14AM, 20B
Stand Included No — sold separately
Brand Magnaflux

SPECIFICATIONS COMPLIANCE

  • ASTM E709-08 (Sections 20.6.1 & X5)
  • ASTM E1444/E1444M-12 (Section 7.2.1)
  • ASME (Section V, Article 7: T-765)

DAILY INSTRUCTIONS (INCLUDING NEW BATH)

1. Let pump motor run for up to 30 minutes to agitate the suspension

2. Flow the bath mixture through hose and nozzle for a few moments to clear hose.

3. Fill the centrifuge tube to the 100 ml line.

4. Place the tube in the stand. If required by written procedure, demag the tube (note that the stand is non-ferrous and will not interfere with particle settling). Let the tube stand in a vibration-free area to allow particles to settle. Settling time is 30 minutes for a water bath or 60 minutes for an oil bath.

The gravity settling method applies to either oil or water suspension. In hot weather the water bath should be checked more often as is it more volatile than oil. Therefore, as water is lost by evaporation, it must be replaced. The settled particles (measured in ml) in the bottom of the tube indicate the amount of magnetic particles in suspension. A UV lamp, such as the Magnaflux EV6000 LED UV-A Lamp, must be used for fluorescent particles.

Do not include dirt particles in your centrifuge tube readings. They usually settle on the top of the magnetic particles. Dirt will not fluoresce under UV-A irradiation.

In visible particles, the appearance of dirt is very different than that of the particles. Dirt will be coarser and irregular in shape. See illustrations for recommended settling volume.

BATH MAINTENANCE TIPS

To maintain proper bath suspension during inspection requires that it be agitated prior to and while the bath is in use. The agitator pipe should be removed and thoroughly cleaned monthly or more often, if needed. Also, check area where sump screen connects to tank, clean and remove any foreign material that may restrict flow.

Constant use of the bath requires a daily check for evaporation of oil or water, loss of particles due to carry off and contamination. Eventually the bath will become so contaminated by dirt, lint, oil or other foreign material that efficient formation of indications will become impossible.

Contamination can be checked by noting the amount of foreign material that settles out with the particles in the centrifuge tube. Covering equipment, when not in use, will reduce contamination and evaporation.

Product Data Sheet