Geoff's Woodwork

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Abrasives

The main modern abrasives used in the wood trades:

a. Garnet  is for hand and machine sanding and is made from natural crushed garnet stone ~ for sanding wood ~ harder than glass or flint papers,  provides sharp cutting edges ~ cuts quick, long lasting ~ does not build up heat that may burn finishing's or the wood.  Excellent for cabinet makers in both soft and hardwoods and those who require a good smooth finish.

b. Aluminous oxide  is used chiefly for machine and portable power tool sanding but is also available for hand sanding and in particularly, dense hardwoods.  There are brown and pink varieties (occasionally dyed black) but are used for metals.     The white form is dyed orange for wood finishing.  The tough and hard grains of this material does not disintegrate under high pressure.  It is a preferred option to silica carbide papers for smoothing wood.

c. Silica carbide  once used chiefly for the leather trade and metal work with some uses in sanding floor surfaces.  Commonly known as 'wet and dry' paper.  Now more available for hand and machine sanding.  Suitable for wet and dry applications.  Excellent  for cutting back and polishing very hard finishes such as cellulose, polyester, paints, glass, plastics and non-ferrous metals.  A  hard and expensive grit is the main ingredient of 'carborundum'.  

Fine pale grey papers are also available 'coated' with a zinc-oxide dusting as a dry lubricant that are excellent for cutting back between polishing coats of French polish.

Older and perhaps redundant abrasives

You will still across the following papers or reference to them:

a.  Glass paper.  Pale yellow in colour. Originally crushed sand but usually made by the apprentices in the workshop by crushing old glass bottles and grading through sieves to obtain the grades.  Now made from powdered glass. It is slow cutting, relatively soft and soon wears out or becomes clogged up.  Chief uses were 'sanding' down paintwork.  Used for finishing wood, care must be taken to go through the grades so it does not scratch.   Still hangs on and is still available as a quick cheap and cheerful abrasive.

The '00' or 'Flour' grade is still preferred by many French polishers for cutting back through the layers of polish.   'Worn' flour paper i.e. slightly clogged up was used for the final finishes although two papers rubbed together to remove the bite was also used.   Still widely available.

Grades are known as , 'flour', 00, 0, 1, 1 1/2, Fine, Middle, Strong.

b.  Flint Paper.  Slightly harder grit than glass paper.  Used for hand sanding.   Largely replaced by the more modern papers.

Grades include: 4/0, 3/0, 2/0, 0, 1/2, 1, 1 1/2, 2, 2 1/2, and 3.

Backing material.

The backing material is usually cloth or paper. The cloth variety is more expensive but lasts longer under hardy conditions. Probably used extensively in the motor trades and engineering rather than woodwork.

Open/close coat.

Open coat is used chiefly for machine sanding. The open pore helps to prevent clogging. The speed of rotation provides a smoothing action.  Closed coat is for hand sanding papers.

Grit sizes.

Grit sizes are normally standardised but a numbered system used by the Flint Papers may still be come across on some papers and referred to in some text.

Approximate comparable grit sizes between the different systems:

Common Use *

Grit Size

WW
Grade

Flint Paper

Glass Paper

 

400

11/0

   
 

360

10/0

   
 

320

9/0

   

 

280

8/0

   

Delicate and between polishes

240

7/0

   
 

220

6/0

   

Finishing

180

5/0

 

00 Flour

 

150

4/0

3/0

0

Start here for close grained hardwoods

120

3/0

2/0

1

 

100

2/0

0

1

 

90

0

2 Fine

Levelling & Preparatory

80

     

 

60

1

2 Middle

Paint removal

50

1

1

2 Strong

 

40

1

2

2 1/2

 

36

2

2

3

 

30

2

3

 

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text and grafics G.E. Malthouse ~ all rights reserved

reference sources: Furniture Making - E Joyce, Purpose Made Joinery - P Brett - Collins Woodworking Manual -  Carpentry & Joinery, Porter & Rose - Axminster Power Tools catalogue.

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Last uploaded 25th September 2007