FAQs About Röchling Glastic Composite Products

The following are frequently asked questions about Röchling Glastic’s line of laminates and shapes. Have a question that you do not see answered here? Click on the link below to submit your question and we will promptly reply with an answer.

Q. Will flat sheet retain its properties if sanded?

A. No, the veneer of the laminate sheet enhances water absorption, track and arc resistance.

Q. What is the theoretical corona inception and/or extinction of a given material?

A. The theoretical corona inception is typically 70.7% of the tested perpendicular dielectric strength of the material. The extinction is the same, but in practical testing, the value is lower than the inception due to heat build up.

Q. How much does a flat sheet weigh?

A. Typically 29.484 grams per cubic inch, or 9.360 pounds per 1" x 12" x 12".

Q. In the specification "Electrical Strength- Parallel S/S in Oil", what does S/S mean?

A. S/S means Step By Step, or a method of testing as outlined by an ASTM Standard.

Q. In the specification "Electrical Strength- Perpendicular S/T in Air/Oil", what does S/T mean?

A. S/T means Short Term.

Q. What is the minimum distance between potentials to be used with Röchling Glastic materials?

A. Generally, failures between potentials are flash over (through air). Use typical electrical engineering practices of spacing.

Q. What is Dielectric Constant, or Permitivity?

A. It is used to determine the ability of an insulator to store electrical energy. The dielectric constant is the ratio of the capacitance induced by two metallic plates with an insulator between them to the capacitance of the same plates with air or a vacuum between them. Dissipation factor is defined as the reciprocal of the ratio between the insulating materials capacitive reactance to its resistance at a specified frequency. It measures the inefficiency of an insulating material. If a material were to be used for strictly insulating purposes, it would be better to have a lower dielectric constant.

Q. What is the Poisson's ratio of our materials?

A. Poisson's ratio is the ratio of transverse contraction strain to longitudinal extension strain in the direction of stretching force. Tensile deformation is considered positive and compressive deformation is considered negative. The definition of Poisson's ratio contains a minus sign so that normal materials have a positive ratio.

Since this physical property is not commonly requested in the thermoset plastics industry, we do not publish it.  We also do not have the capability to measure this ratio.  The value is estimated at .3.

Formula:

Q. What can be used to seal laminate material after machining?

A. Any electrical varnish such as "Hetrolac" supplied by Ashland Chemical in Columbus, OH USA. While there is some benefit to coating the edges, there is little or no benefit to coating molded surfaces.

Q. What is RMS voltage?

A. RMS voltage of a pure (‡) sine wave is approximately 70.7% peak voltage. If you read voltage with a voltmeter you are generally given the RMS voltage of the waveform. Some meters display an 'average' voltage, which is very close to RMS. When reading voltage with a voltmeter, the display indicates the RMS or average voltage not the peak or peak-peak voltage.

Q. What type of adhesive should be used to bond laminate sheets?

A. A two-part epoxy adhesive works well. The mating surfaces should be sanded and cleaned prior to bonding. Master Bonds, polymer adhesive (two part epoxy) EP45HT 154 Hobart Street, Hackensack NJ 07601 USA has been used for this purpose. Refer to the manufacturers specifications to be sure that it is acceptable for the intended application.

Q. What should I use to cut laminate sheet?

A. Glastic recommends that you use a diamond-tipped saw to cut laminate sheets. Carbide-tipped, or high-speed steel blade will cut on a limited basis. An evaluation of how much material needs to be processed is needed. As an example, for a cut of a few inches in length, high-speed steel blade should work well. If there are a number of feet to cut, consider using a carbide blade. If a number of yards are to be cut, diamond blades should be considered.

Q. What is the radius of the angle and channel?

A. The tolerances are +/- 1/64" for a radius under 3/16" and +/-10% for tolerances on a radius above 3/16".

Q. What are your standard sheet sizes?

A. 36"x72", 48"x60", and 48"x96."

Q. What lengths of rod, dogbone, angle and channel are available?

A. Rod and Dogbone - 9 ft., Angle and Channel - 10 ft. Custom lengths are available with minimums.

Q. What is the difference between S, HT and CH, Glastherm®?

A. Basic differences between the grades of Glastherm® are the types of resins used and the glass density of the construction. Each increase in properties between the grades is due to the use of more heat resistant and stronger resin system and/or increased glass density.

Q. What is the tolerance for length and width of molded product and length of pultruded product?

A. +2" /-0

Q. How can I convert imperial to metric or vice versa?

A. The basic formulas are:

Q. What is the difference between 1603-2A and 1603-2D?

A. The diameter of the inserts used are different.

Q. What is the difference between the version between 4640-1E, 8A, 8B and 9A?

A. The size, shape, and electrical capabilities of the insulator do not change although the quantity and location of the inserts differ between the configurations. The inserts are arranged concentrically on the top and bottom of the insulators using a 2" bolt circle diameter (BCD). Contact your customer service representative for your specific needs.

Q. Does Röchling Glastic have material that meets Military and IEC specifications in addition to NEMA specifications?

A. NEMA specifications are cross-referenced to Military and IEC Specifications.

NEMA Spec. MIL-Spec. IEC Spec.

GPO-1 MIL-I-24768/4 60893-3,UP GM 201

GPO-2 MIL-I-24768/5 60893-3,UP GM 202

GPO-3 MIL-I-24768/6 60893-3,UP GM 203

Q. What are typical height and thread tolerances on Röchling Glastic standoff insulators?

A. Height tolerances on insulators are typically 1/64", although the variation on injection molded product will be much tighter than that of compression molded. Insert threads are class 2B for imperial sizes and 6H for metric.

Q. How do I choose the correct material thickness based on perpendicular dielectric strength?

A. Perpendicular dielectric testing is done using an ASTM D-149 specified standard thickness of 1/16”. When determining the dielectric capability of a sheet’s thickness, take the following relationship into consideration.

Q. Where can I locate a distributor in my area?

A. Click on this link to go to the "Contact Us" page

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