Pressure gauge lense

[ubxdiver]

My pressure gauge crystal/lense needs replacing. Anybody suggest a resource? I've tried welding and HVAC joints.
Above water the gauge in almost unreadable, in water I can vaguely read the gauge. I'd like to replace it.

[simonbeans]

Is the lens glass or plastic?

[ubxdiver]

Made of plastic.

[simonbeans]

I have been using a buffing compound on a wheel and have had great success getting scratches out. The compound I got from my least favorite store (Harbor Freight) and it is white. Buff gently and check it frequently. Do NOT over-heat.

[Bryan]

Alan is right, HEAT IS THE ENEMY....Google search for restoring acrylic / plexiglass windshields on boats from the 50's and 60's. Fiberglassics is a good site... Lots of step by step instructions and pictures with results I would not have thought possible from looking at some of the before pictures. It is a similar process to cleaning up headlight covers on newer cars.

[Herman]

I have done a number of the UDS ones that appear to have some kind of chemical reaction on the inside. Deep scratches are harder to get out, personally I leave the deeper ones on the outside.
Here is how I do them.
Before

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Dissambled

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Lens damage

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I sand the lens with wet sandpaper, starting with a 600 grit, moving to a 1000 and finally a 2000. You can find this sandpaper in auto stores. I tape the sandpaper to a flat surface, use lots of water and polish it using a figure "8" motion. I put a couple of dots on the side of the lens I am NOT working on with a sharpie so I can keep up with which side I am working on, otherwise you have a hard time deciding which is which once you get started.

P1010200web.jpg

This is what the lens looks like after it has been sanded with 2000 girt

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After the sandpaper, I use fine auto polishing compound applied with a cloth tip attachment on a Dremel tool. This is what it looks like....after a good bit of polishing. And yes there is a lens installed and it is the same one in the before photo.

P1010202web.jpg

[Bryan]

Herman when you can please make your post into a pdf and send it to me so I can archive it for future downloads or Email. Great post! Thank you

[antique diver]

Nice job, Herman. I have often wondered what caused those USD gauge lenses to mess up on the inside. Just about all those from that era have the same issue. Maybe some chemical reaction to the plastic used in the luminescent gauge face?

In case of a lens that just isn't repairable you can go to a plastic supply source and get a similar thickness of acrylic or Lexan and cut your own replacement. I haven't done it with a gauge yet but once replaced a badly scratched lens in my Superlite hat with Lexan that I obtained locally. I used Lexan for that since it is just so strong, and you don't want a broken lens in that piece of gear. I tested a 1/4" thick plate of scrap Lexan with a shotgun blast of 7-1/2 birdshot from 15',(not installed in my SL!) and while it was badly damaged, it did not crack, and would not have leaked water if it had been in place as my lens.
Tough stuff.

[Herman]

Herman when you can please make your post into a pdf and send it to me so I can archive it for future downloads or Email. Great post! Thank you

Will do.

[crimediver]

I have a badly scratched lens on a General Aquadyne bandmask that I have been debating trying to restore. The advice above has gotten me motivated and I just may try my hand at it.

[captain]

http://www.eplastics.com/Plastic_Polish