PTFE (Teflon®) Moulds

Created by Karen Darley, Modified on Fri, 24 May at 3:09 PM by Kathleen Patrick

PTFE (Teflon®) flat embedding moulds such as RL090 (16 cavity) and RL091. (3 cavity), are designed for use with methacrylate or acrylic resins including LR White, LR Gold and GMA. 

Two stage filling

  1. The cavities in each mould should be partially filled with resin and the sample positioned. 
  2. Next the cavities are overfilled so that resin from one block cavity just spills into the adjoining overflow/border cavity. 
  • The recessed overflow/border cavity around the block cavities should not be filled. 
  • The metal frame should be removed from the mould prior to use for polymerisation. The frame is used to restore flatness to the mould after the blocks have been removed. 

Exclude Air

Low viscosity resins are oxygen sensitive during polymerisation. The cavities in the PTFE/Teflon® moulds can be covered with two Thermanox® cover slips (22 x 60mm) or a strip of ACLAR™ FILM. These coverings will ensure anaerobic polymerisation with either thermal or low temperature UV polymerisation.

The cover slips and/or film are placed over the resin-filled cavities in the following manner:

One end of the cover slip or film is placed at the end of the recessed area surrounding the block cavities and held in place gently with a wooden stirring stick or similar device. With a tweezers, grip the other end of the cover slip or film and gently lower it down over the resin-filled cavities. This will eliminate air bubbles and allow the excess resin to wick out to the edges of the recessed border, ensuring an anaerobic environment underneath the cover slip or film.

Do not overfill the cavities to the extent that the resin will wick beyond the recessed border cavity. If this happens and the metal frame is being used the mould and frame will become bonded together.

ACLAR embedding film is:

  • Optically clear
  • Sectionable with glass or diamond knives
  • Easily removed from polymerised plastic
  • Resistant to all EM chemicals

GL081 Thermanox coverslips are:

  • Easily removed from polymerised plastic
  • Sectionable with glass knives

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