Invisible Ink

You can use ultra violetray fluorescence pen. so that you have to use uv lighting the words you wrote to display. if you are interested in the uv printing ink you can printing on material like grass and ceremic etc. we can offer you these ink and pen and other writting tool on grass etc.

Hi.

Thankyou for replying to my request,if you have any dealer in india please send me the detail to nageshrao_sridhar@rediffmail.com

dear sir, i am as an optician in pakistan i want write my company logo on eye glass that can only be seen by fog. please tell me how can i write invisible . thanx Asad

Dear Guest,

My advice is that you use a masking techniques and blast a very small area, perhaps in the corner of the lens, with a very fine abrasive. You should after all want your customers to be proud of your Company Logo, discretely displayed just near the frame. Etching with HF acid in a fume cupboard might be an option? again masked, but I am not qualified to advise. Laser ablation is also a potential solution. perhaps demanding a slightly higher initial capital investment.

At a guess, a suitable adhesive tape could theoretically be used to protect most of the glass lens. The logo could be printed onto the lens in a water repellant ink and then a water soluble latex applied and allowed to dry. this layer of latex would become the mask. Well worth an experiment or two. A compressor from an old refrigerator would be quite adequate for such fine abrasive blasting. You might need to make a very fine abrasive blast gun. Two fine tubes meeting 'Y' fashion, i.e. one tube delivers compressed air, the other tube draws in fine abrasive from a reservoir, under 'suction' (pardon the expression)...Bernoulli Principle at work.

Cnpower is right about the ultra violet pen, make sure it is a waterproof version, most 'security' marker pens are. As for engraving glass, why not go round and ask a local dentist if he has spare worn diamond drills he is throwing away. You can even use them without a drill. Just stick them in an old ball point pen with some epoxy glue/whatever. Or toy model maker supply shops sell suitable drills, a 12 volt one could work off a car battery. Good Luck.