Cessna 172 Maintenance Manual page 129

(11) Stop drill cracks using a No. 30 (0.128 inch) drill.
(12) Remove all ragged edges, dents, tears, cracks, and punctures.
(13) After removal of damaged area, leave edges parallel to any square or rectangular edge of the
unit.
NOTE: Damage adjacent to a previous repair requires removal of old repair and inclusion of
the entire area in the new repair.
(14) Round all corners.
(15) Smooth out abrasions.
(16) Vacuum thoroughly to remove all chips, filings, dirt, etc., from bay area.
(17) All surfaces to be sealed after repair should be thoroughly cleaned by wiping with a clean cloth
dampened with methyl propyl ketone (MPK), acetone or similar solvent, and dried with a clean
cloth before allowing solvent to evaporate. Always pour the solvent on the cloth to prevent
contaminating solvent. Do not allow cloth to drip. Never use contaminated solvent.
(18) Any repair that breaks the fuel bay seal will require resealing that bay area, refer to applicable
Maintenance Manual, Chapter 28, Fuel Tank Sealing - Maintenance Practices for sealing
materials and procedures.
CESSNA AIRCRAFT COMPANY
SINGLE ENGINE
STRUCTURAL REPAIR MANUAL
© Cessna Aircraft Company
57-11-00
Page 802
Jun 1/2005