Typical Skin Repairs - Cessna 510 Mustang Structural Repair Manual

1. Types of Skin Repairs
A. Polishing repairs - Damage that can be corrected by polishing.
2. Polishing Repairs
CAUTION: Contact Cessna Customer Service Structures at (316) 517-6061 or at csstructures@txtav.com for
corrosion more than 15% of the skin thickness.
CAUTION: No repair of corrosion damage to Principal Structural Elements (PSE) is allowed without prior approval
of a Cessna DER authorized damage tolerance engineer. Refer to Principal Structural Elements.
A. These repairs can be done on a surface where:
(1) Damage does not go through the cladding.
(2) Damage is less than 0.002 inch (0.55 mm) in depth.
(3) Damage width is not more than 0.25 inch (6.3 mm).
B. To find out the depth of damage for polishing repairs, do the following test:
(1) Clean the damaged area. Use methyl propyl ketone or other suitable grease removing solution.
(2) Place a drop of scratch testing solution on the damaged area. Let the solution remain on this area not less than one
minute or more than three minutes.
NOTE:
(3) Clad areas are not affected by the scratch testing solution, exposed core material will turn dark.
(4) Immediately after the test, rinse the tested area with clean cold water.
(5) Apply a 5 percent chromic acid solution to the test area, then remove excess chromic acid by wiping with a clean
cloth.
(6) Damage that does not penetrate the cladding is not greater in depth than 0.002 inch (0.55 mm).
C. Polishing Procedures.
CAUTION: Use rubber gloves when you work with Kelite L17. When you work on lower surfaces, wear a face
shield.
(1) Clean the damaged area with Kelite L17. Remove as soon as possible with water.
CAUTION: Maximum width of stoned area shall not exceed 0.25 inch (6.3 mm).
(2) Rub the length of the damaged area until the damage is removed with a scotchstone and water.
(3) Smooth the stone marks with 400 grit or finer wet or dry sandpaper. Rub in the direction of the damage.
(4) Buff the damaged area with a brown wrapping paper buff saturated with light oil and Bon Ami. Rub in the direction of
the damage.
NOTE:
(5) Polish the surface to remove the abrasion marks with jewelers rouge and a soft cotton cloth wrapped around the
index finger. Rub in the direction of damage. Don't polish in a circular motion and limit polishing to damaged area.
(6) Blend the reworked area to the surrounding surface with the brown wrapping paper buffing pad and oil rub with the
grain of the metal until you get a satin finish.
(7) With chemically treated waste (all-in-one-polish saturated waste) polish blend the area to the desired finish.
CAUTION: Use rubber gloves when you work with Kelite L17. When you work on lower surfaces, wear a face
shield.
(8) Final blend with Kelite L17 then rinse with clean cold water.
3. Electrical Bonding Check of Skin Repairs
NOTE: This check is required for all skin repairs that require addition of fasteners or a skin patch.
A. Skin Repairs in a Fuel Cell or Area with a Concentration of Fuel Vapors
CAUTION: If the butts of rivets are not correctly sealed, in case of a lightning strike, an electrical arc from the
Copyright © Textron Aviation Inc.
Retain printed data for historical reference only. For future maintenance, use only current data.

TYPICAL SKIN REPAIRS

Scratch testing solution is made up of 20 grams KNO (Potassium Nitrate), 10 grams NaOH
(Sodium Hydroxide) and distilled water. Distilled water will be added in quantity to make a 100
milliliter solution.
You can make a paper buff by folding brown wrapping paper in a 6 inch by 6 inch (15 by 15
mm) pad.
FOR TRAINING PURPOSES ONLY
ISSUE 02 , JAN 2018
Model 510 Structural Repair Manual (Rev 2)
51-70-02-0 (Rev 2)
3
Print Date: Wed Mar 21 05:12:22 CDT 2018
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