Instrument screen, casting a new screen in an old frame.

[t140v]

Put quite a bit of thought into my mould design as I wanted to produce a full new screen or to be able to allow an old frame to be used to cast a new clear screen into it.
Some modifications to the original screen frame would need to be made to allow pouring and vent points to align with the vent holes in the mould.
Step 1 machine out the old screen.
Used a 6mm tungsten carbide end mill in my trusty Chinese lathe.


Step 2 fill the ends of the original frame with resin.


Step 3 Drill the pour and vent holes in the ends of the frames.


Step 4 put the frame inside the mould and place the mould in an oven for a couple of hours at 60c .

[t140v]

Step 5 Fill the mould with liquid resin trying not to introduce any additional air into the cast.

Step 6 Put the mould into a pressure chamber for 1.5 hours at 50psi

Step 7 Remove the moild from the pressure chamber and put in the oven for 6 hours.

[t140v]

Step 8 Remove from the oven and allow to cool to room temperature before opening.
Step 9 Carefully open the mould and remove the frame and new screen.

Step 10 Fit the recast screen and frame on the clocks remove any excess resin ready to paint satin black.

[t140v]

Step 11 Mask up the clear screen section then spray the frame and ends satin black to cover over the fill and vent channels.


Hope you found this interesting, I have been working on this for 3 years sometimes they come out ok others need some rework but overall there is a big improvement in the clarity of the screen.


Regards Stuart.

[rpr851r]

Fantastic work.

[wayne]

That is one helluva an exercise. But the outcome is brilliant.

Thanks for the contribution Stuart.

[Jess]

Looks great! very creative.

Will you be providing them for others?

Best,

[t140v]

If somebody wanted one to read their clocks, or finish a restoration then I would be willing to make one or replace the screen, as long as they could accept possible imperfections in the face, as I have said I have been making them for 3 years trying different pressures and resin temperatures and every one has had a small bubble or inclusion, but when they have been worked on and polished it is very difficult to detect the imperfection as seen in the ones above.
At the end of the day they are home made in my kitchen and garage not in an injection moulding factory and any I make will be the best quality that I can do given the constraints of my equipment.

Regards Stuart.

[goandy]

Still way more awesome than a cloudy yellow screen! They look pretty darn good to me Stuey!

I still like my heated and moulded perspex job (relatively easy) but yours is pretty much how they were made at the factory so well done!

[HGH 770N]

Thanks Stuart
Your work is always gratefully received and 1st class for home made .
I have seen several attempts over the years to replace the screen,from glass that touches the fingers and failed shaped perspex not like Andy perfected.
Your mouldings are 100% better that a screen you can’t see through.