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Laird Plastics
Lakwijk Kunststoffen

Introduction

On the top of this page you can find an overview of all brands that supply spacer material.

A spacer is generally something used to create a space between two objects, often to properly position them.

A spacer in al electrostatic panel must have perfect insulation characteristics.

Stiff foam materials are well suited because they are mostly air. By using stiff foam tapes simplifies construction significantly.

Fiberglass is hard to cut (you need a carbide blade), and the dust from sawing is a health hazard, but epoxy will bond to it. Acrylic or other plastics are easier to work with, but epoxy may not form much of a bond to them.

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Suitable construction materials by Neil S. Mckean

  • Styrene
  • Polycarbonate
  • Plexiglas

The critical factor for selection of the spacer material is the dielectric constant, as this parameter determines in part the capacitance of the speaker. Any energy that used in driving the frame capacitance is wasted and should be kept to a minimum. This is achieved by a low value of dielectric and minimisation of the spacer area. The frame capacitance is proportional to spacer area. The table below details some common plastics suitable as insulating materials. Plexiglas and polycarbonate can be used but are more expensive although they have suitable D.C of about 3-3.5.

Dielectric constants of some common plastics suitable for use as insulating spacers for ESL panels.

Material Dielectric Constant
Teflon 2.1
High Impact Styrene 2.9
Plexiglas 3.2
Nylon 3.5
PVC 4.6
Epoxy Glass 5.8

From a cost point of view styrene is about the best and has a low dielectric constant and still maintains a high dielectric strength, so resisting breakdown and arcing. As stated earlier the styrene bonds well and can be chemically welded with the appropriate solvent, in this case xylene or toluene. Alternatively, less toxic plastic adhesives and contact adhesives give satisfactory bonds as there is relatively little stress on these bonds.

Bonding aluminium or other metals to styrene is best achieved with good quality contact adhesive. There may be a query with the longevity of the bond in certain climatic conditions with contact adhesives but the latest high quality types promise upwards of 25 years without problems and strength can be added by clamping the panels to a rigid frame (made from MDF) at least along the largest panel dimension with an appropriate gasket between the surfaces for acoustic isolation.

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