Prepared by
ROY ELLIS
IMVS Division of Pathology
The Queen Elizabeth Hospital
Woodville Road, Woodville, South Australia 5011
Email: roy.ellis@imvs.sa.gov.au
Sections will not ribbon
A knife clearance angle too fine or too great can result in sections not ribboning. Both we have discussed so there’s no need to go into it again. If your knife clearance angle is always correct then all of the problems associated with incorrect clearance angles just will not happen.
A dirty knife edge usually causes sections to stick to the knife edge so that it is difficult to get them to ribbon. So it is important to keep the knife edge clean, especially the back of the knife. Use xylene followed by alcohol. If you use xylene alone being an aromatic hydrocarbon and slightly oily it does leave a fine film of material on the back of the knife ready to catch the next section. Alcohol removes the oily film and leaves the surface very clean.
If the wax surface is too cold the sections will not stick together as they come down the knife but will drop off the knife as each section is cut. The palm of the hand placed on the block for a few seconds will overcome this problem.
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© Roy C. Ellis 2002