1. Calculate and cut the external size of matboard for the piece of artwork.

2. Calculate the width of the mat border taking into account the width of the fillet.

Note: The easiest way to work out the width of the border is to think of the mat as an outer mat in a double mat combination. Take off the width of the fillet from each side.

3. Decide whether to cut a normal or reverse bevel.

4. Cut the window in the mat.

5. Measure the length and width of the window and cut the fillet to fit.

You can calculate the fillet size the same way as you calculate your external sizes except you do not include the 2mm allowance. The "y" measurement becomes the distance from the part of the fillet you wish to show and the back edge of the fillet.

6. If the fillet is thick enough it can be joined at this stage with a 5mm vnail. Otherwise it it usually sufficient to stick the fillet to the mat with double-sided tape or hot melt adhesive.

7. Apply double-sided tape to the back of the mat parallel to the window and as close as possible to it.

8. With the mat face up align the fillet or pieces of the fillet with the opening in the mat.

9. Adhere the fillet to the mat by pressing it against the double sided tape.

10. Turn the mat over and measure the distance between the outside edge of the fillet and the edges of the mat.

11. Cut suitable thicknesses of foamcore to fill the distance measured in stage 10.

12. Adhere the filler strips to the back of the mat with double sided tape.

Do not to leave any gaps in the filler because the mat will buckle in time.

13. If the fillet is to touch the artwork an additional mat or liner strips can be cut and stuck to it to act as an acid barrier.

14. Hinge the artwork as normal.