Artificial Horizon MK4B glass

Pity it’s not a 4D you need!

yep :/

Thanks for the replys.. this sounds a much bigger job than I thought it would be….maybe I would be better finding another one. The diameter is 83mm.

If it’s the same as the mk6 then it’s 1/4 inch thick glass, with a tightly controlled hole in the middle. They have a habit of cracking from the center hole.

Also it’s a solder sealed case, with a dry inert gas fill;- 80%He and 20% N2. You need to find the edge of the solder strip, lift it and unpeel from around the case.

I’ve changed broken mk6 glasses in the past;- I water jet cut the new ones to size in 6mm float glass (using a mirror manufacturer to accurately cut the tight radii) and then used a spade drill to bore the center hole using a simple positioning jig located on the OD. The original glasses were flash copper plated on the edges and then soldered into the bezel. The new wings level marking was made from laser cut white fablon. I used epoxy to bond the glass into the bezel as per the scheme used on the FH14 series. Solder sealing the case is quite an undertaking but if it’s just static you won’t need to do this.

From memory, solely replacing a glass is about 4-5 hours work and with the cut blanks costing about £20 each.

Hmm, might not be that easy.

Just looked at a mk6 and the front is held on by a soldered band and the glass is cemented in from the back. Also, the ‘aeroplane’ may be fixed to the glass.

I get glass cut. I do have a large stock of different original glasses. Not sure I have a 4b. What’s diameter?