Sections roll up when cut

WHY?   

• A blunt knife can cause this to happen as well as if the Knife clearance angle is too great because having the angle too great is very much like presenting a blunt edge to the block.

• If the micrometer is set too thick then sections can also roll up. Ideally sections should be cut at 3 to 5µ to demonstrate most tissue elements, but if you must have thick sections like those that are required to demonstrate some neurological elements then make sure that your knife is very sharp.

• The wrong melting point wax for the conditions is one we also covered before as causing sections to crumble or tear. Well sections rolling up can also be caused by using a wax with the wrong melting point for the conditions. In cold climates a wax with a melting point of around 54°C is ideal. In temperate climates a wax with a melting point of around 58°C is better. But in a tropical climate a wax which melts at about 62°C should be used. Of course if you are working in an air conditioned environment then that also needs to be considered.

• If the block is too warm this can also cause the sections to curl.

• And if the top and bottom edges of the block are not parallel this can also cause the effect although I don’t believe that this is a major cause unless the blocks are very large and there is only a small clearance between the top of the knife and the bottom of the block.