The Thales MCDU unit uses a CRT for its display function.

To convert the unit the CRT was substituted with an LCD; an advance display type, smaller, thinner in profile and lighter in weight. To simulate the CRT a fitted glass is mounted on top of the LCD.

Original Thales MCDU unit with keyboard removed. The CRT black borders are clearly visible.

There are some challenges – The silver metal frame edges of the LCD can be seen on the edges of the glass; it should be blocked from operators view to complete the illusion. Multiple different materials were trialled – duct tape, double sticky sided tape, cardboard frame cutouts, and neoprene rubber material.

Two neoprene rubber cut outs and card frame 

Black tape and the frame cutouts did not give good results. The MCDU looked tacky with the black borders having a stuck on appearance.

I was optimistic with the neoprene rubber as other builders had success with similar material. Measurements of the black border were recorded and designed in SketchUp for accuracy (Skp file available here). The rubber was cut carefully with a razor blade and carefully placed on the glass. No tape or glue was used to adhere the rubber as stretching can occur and distort the shape.

The results were surprising; the rubber appears to blends in with the glass and LCD replicating the black CRT borders.