New curved instrument screen, following on from Goandy

[t140v]

Evening all,
I watched with interest when Goandy made his plaster of paris and cement moulds of the curved instrument screen and having successfully made a mould to reproduce the indicator lenses I decided that it could be possible to create a mould to reproduce the full screen not just the clear curved section.
This would allow a complete new screen to me made, or if the old screen with frosted screen is used the clear section could be milled out and a new clear section cast into the frame.
The first task was to design a dual purpose mould, one that could cast the full screen or when the milled out frame was inserted into the mould would allow the resin to flow in and replace the milled out section.
Second task was to locate a curved instrument screen as close to new condition as possible to use as the master in my mould, the rubber will replicate finger prints so ideally the original needed to be perfect.
Thirdly estimate the quantity and type of rubber to use, has to be soft enough to release the copy but strong enough to support the empty mould without sagging in the lense area.
I have all of the photos but now need to edit them all to bring down to the 1mb size required by the forum.
Regards Stuart.
The start of the mould, filled the back of the cover with rubber then set up to make the front half of the mould.
The ends have been filled with rubber to make the mould less complicated and make de moulding the cast easier.

[don07tncav]

Looks great Stuart!

[wayne]

Stuart, you'll probably have difficulty posting via the board's own picture gallery. I clean this up regularly but it's still near its limit. If you can't do it, send the pictures to me and I'll post them on my Flikr account. I pay to keep that alive and I'll send you the links to use in your post.

[t140v]

Oct 21, 2019 18:41:32 GMT -5 wayne said:

Stuart, you'll probably have difficulty posting via the board's own picture gallery. I clean this up regularly but it's still near its limit. If you can't do it, send the pictures to me and I'll post them on my Flikr account. I pay to keep that alive and I'll send you the links to use in your post.

I'll give it a go Wayne, if I have problems will forward to you.

Regards Stuart

[t140v]

To ensure the screw holes were in the correct position aluminium pins were inserted so when the mould was made the pins could be positioned inside the mould to make holes for the screws.
The photo of the completed mould showing the aluminium pins in position

The first cast and first problems, air bubbles in the face, I found that it is possible to drill into the bubble, refill with resin and allow it to set under pressure before sanding and repolishing the screen.

Attachments:

[t140v]

This photo shows the full cast including the screw holes in the clear frame the air bubbles have been drilled filled sanded and polished, next to the original master, the last stage is to mask the screen and paint satin black.

And finally the finished screen on a clock face.

Attachments:

[t140v]

Next section will cover the milling out of screen faces and recasting a new face into the old frame.

[goandy]

Wow. That's awesome. Well done!

[h2e Al In Aus]

great work , good to see photos , thanks

[re5rotary]

Fantastic well done. regards Terry