Platic Optical lens

[azeemsarwar]

I am from Pakistan. I want to know,how to finish
an unfinish plastic Cr-39 lens.
                I took a blank of cr 39 and changed its power by grinding its concave surface on a machine, which is usually used for glass lenses. During this procces the concave surface lost its transparency, now I want you to tell me the coating or other method to make it transparent again. If there is any coating that can do the job, plz tell me its name and the price that you can offer for it. I am sending you the photographs of the lens before and after the process.


anxiously waiting for your reply

                                                             Mr. Sarwar
                                                Phone # 00923214061992
         Email ID: azeemthebest1@hotmail.com

[ARD]

I would imagine that you will need glass polishing equipment, which is not going to be cheap.

[dobson]

I do a lot of lapidary (gemstone) work, and I have found that soft materials polish differently than glass. Hard stones polish well with diamond, medium stones (like glass) work with cerium oxide, and soft stones (including resin) can be polished well with tin oxide. Tin oxide is fairly inexpensive and common, getting a pound of it shouldn't be a problem. 100,000 mesh size should be sufficent. I polish convex surfaces on a padded leather wheel with plenty of water.

Phillip

[Paul Kay]

Underwater photographers have a similar problem when their acrylic dome ports get scratched or scuffed. I've used jeweller's rouge (which can be bought as a silver polish - Goddards silver polish paste is one) to hand polish out scuffing and the like. If your plastic lens is effectively scuffed all over, then hand polishing might be a solution using this rouge and a cloth - but it will be both slow and tedious. It is a good finishing material though.