The polystyrene thickness standards are recommended for use with several models of ultrasonic gages. Ultrasonic gages emit a high frequency pulse of sound that travels through the material and reflects back when it encounters a different density material. The thickness of the material is calculated based on the time for the reflection (or echo) to be received and the speed of the sound in the material. Most ultrasonic gages are preset with a ultrasonic velocity that is representative of most coatings. Improved accuracy can be achieved by adjusting the gage''s ultrasonic velocity to exactly match the material being measured. Some gage models allow you to directly input the material''s velocity if it is known. Other models calculate the material''s ultrasonic velocity by measuring a known thickness of a representative material. DeFelsko provides the ultrasonic velocity to allow the calibration standards to be used with either method.

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Shims, which are permissible for adjusting electronic gages with constant pressure probes should not be used for adjusting mechanical pull-off gages including the PosiTest FM and PosiPen. Shims can act as a leaf spring and cause the probe of a magnetic pull-off gage to be "pushed" off the surface prematurely, resulting in an erroneous reading.

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Certified thickness Standards are used to verify the accuracy and operation of coating thickness gages and are an important component in fulfilling both ISO/QS-9000 and in-house quality control requirements. Contracts often specify that coating thickness measurements be taken by gages whose measurement accuracy is traceable to a National Metrology Institute such as NIST or PTB. Standards are typically purchased as an accessory to DeFelsko coating thickness gages. Many customers find it more practical to verify the accuracy of their own gages in-house, rather than utilize DeFelsko’s calibration services. This is particularly true when many gages are in use and/or when accuracy verification is performed often.

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Although they are made of the same material and cut to the same dimensions, there is a difference in accuracy, packaging and purpose. Neither is suitable for use with magnetic pull-off gages. Certified Plastic Shims (foils) provide an economical alternative to coated metal plate Standards with a reduced accuracy of ±2 µm (±0.08 mil). Gage performance can be conveniently verified in the field or in the lab on a regular basis as called for by some international test methods. Shims are placed over a smooth metal surface (zero plate) and a measurement taken. These strips of flat polyester can be used to adjust (optimize) a coating thickness gage in the intended range of use directly over the customer''s uncoated substrate. Certified Plastic Shims are sold individually or as a complete set of eight. Each Certified Shim is individually serialized and labeled with its measured thickness (mils and microns) obtained with measurement equipment traceable to NIST. They are packaged in their own plastic protective pouch. One Certificate of Calibration showing traceability to NIST is included with each shim or set of shims. Their labeled thicknesses are accurate to within ±2 µm (±0.08 mils). They are for use with electronic magnetic, eddy-current and ultrasonic coating thickness gages. Non-Certified Plastic Shims (foils) are used to provide a quick verification of gage operation when placed over metal and they allow the user to perform practice measurements. Non-Certified Shims are sold as a set of five packaged in one cardboard envelope. Their labeled thicknesses have accuracies ranging from ±5 to 20%. One set is included with most DeFelsko electronic coating thickness gages. They are for use with electronic magnetic, eddy-current and ultrasonic coating thickness gages.

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Each national body has an organization(s) responsible for coordinating the national measurement system that provides traceability of measurement results to reference standards that are internationally recognized. The body in the US responsible for this is National Institute of Standards and Technology (NIST). If equipment is calibrated in another country the calibration of that equipment will reference the respective nation''s responsible organization. Physikalisch-Technische Bundesanstalt (PTB) is Germany''s equivalent of NIST.

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Standards should be replaced when they become visibly worn or scratched.

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Certified Standards are used to verify the accuracy and operation of a coating thickness gage. Select the Standard that most closely matches the measuring range of your gage. See our Ordering Chart for assistance.

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Coated metal standards require little maintenance. If plates become dirty, the epoxy surface can be gently cleaned with a cotton swab dipped in isopropyl alcohol. Do not clean the exposed metal surfaces with alcohol as this will remove any protective films. To prevent rusting, the steel standards come complete with corrosion inhibitor paper and may require periodic application of a light machine oil or 3-in-1 oil to the exposed metal surfaces. Do not apply oil to the epoxy or labeled surfaces. The aluminum plates should not require any maintenance to the exposed metal surfaces. When not in use, all coating thickness Standards should be stored in a cool, dry place. Exposure of the epoxy covered steel to magnetic fields may cause the plates to become slightly magnetic. Magnetism in steel plates can affect readings taken with gages using magnetic principles. Do not store epoxy coated steel plates near magnetic sources. If your plates get exposed to a magnetic source they can be restored by using a degausser.

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Yes, but the cost effective alternative is to trade them in on the purchase of new ones when they become visibly scratched or worn. Trade-in reduces the price of new Certified Plastic Shims by 20%. Additionally, one or more shims can be purchased separately to complete a set.

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Yes, our Standards may also be used with many competitive gages provided they operate on magnetic, eddy current, or ultrasonic principles.

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In most instances, it will be more economical to trade-in Standards for a new set. Trade-in reduces the price of new Standards by 20%.

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