Abrasive Pads

Lee Erb, Chap 1000 Det 5, Arlington TX, Chap 34

Originally published February 1997

There is a CID (Commercial Item Description) 5 April 1996 which supersedes MIL-A-9962A which covers non-woven, non-metallic (nylon) abrasive mats such as Scotchbrite pads. It is important to know if the pads you are using to build your airplane meet one of these specs so that you do not initiate corrosion on aluminum by using the wrong pad (like steel wool).

The pads are not pure nylon but have a thermosetting adhesive holding an abrasive material.

Designations - by Type, Class, and Grade.

Type

Type I - Aluminum oxide (minimum of 94% ALO3 and a hardness of 9.4 Moh's) Color Code is Maroon.
Type II - Natural silicon dioxide (SiO2) (hardness of 6.8 to 7.0 Moh's). Color Code is Tan.
Type III - Silicon Carbide (minimum of 97% SiC and a hardness of 9.6 Moh's) Color Code is gray.

Aluminum oxide, silicon dioxide, and silicon carbide are classed as ceramics. Although one aerospace manufacturer specifies aluminum oxide pads for cleaning before chemical film treatment, I have it on good authority that all three ceramics are okay for aluminum.

At present I do no not know what the abrasive material is for the kitchen variety Green or Blue pads.

Class

Homebuilders need not be concerned of this but our government purchasing people do.

Class 1 - Sheets
Class 2 - Rolls
Class 3 - Disks

Grades

Grade AAA - Grit size less than 10 microns
Grade AA - Grit size 500
Grade A - Grit size 280 to 400
Grade B - Grit size 180
Grade C - Grit size 100 to 150

EAA Chapter 1000 Home Page

E-Mail: Web Site Director Russ Erb at erbman@pobox.com

URL: http://www.eaa1000.av.org/technicl/alodine/abrasive.htm
Contents of The Leading Edge and these web pages are the viewpoints of the authors. No claim is made and no liability is assumed, expressed or implied as to the technical accuracy or safety of the material presented. The viewpoints expressed are not necessarily those of Chapter 1000 or the Experimental Aircraft Association.
Revised -- 21 September 1997