EbolaVirus Posted September 13, 2013 Report Share Posted September 13, 2013 (edited) What is the best crystal you have ever looked through? What are the qualities you look for in crystal and why? AR coatings? Which coatings? Does both sides matter? Do you find crystal thickness makes a difference with clarity? Close or far from the face? Is a cyclops just annoying? Edited September 13, 2013 by EbolaVirus Link to comment Share on other sites More sharing options...
PeteM Posted September 13, 2013 Report Share Posted September 13, 2013 What is the best crystal you have ever looked through? What are the qualities you look for in crystal and why? AR coatings? Which coatings? Does both sides matter? Do you find crystal thickness makes a difference with clarity? Close or far from the face? Is a cyclops just annoying? Mate you are asking for something that covers so much information that it couldnt possibly be answered in a single thread.... Sapphire crystals are graded..... Sapphire has an infinite number of grades: Grades are entirely arbitrary and are decided upon after inspection of each synthetic sapphire batch which has been grown. • Synthetic sapphire is graded by what is important for a particular application, either optical or mechanical • A high grade of sapphire would have little or no light scatter or lattice distortion and be used mainly for the most demanding optical applications • A lower grade of sapphire may have extensive light scatter or lattice distortion, being used mainly for mechanical and structural uses such as bearings, fixtures, and less demanding optical applications • An ultraviolet (UV) grade sapphire or non-browning sapphire will not solarize on exposure to UV light • An infinite number of grades fall between the high and lower synthetic sapphire grades, with each sapphire manufacturer giving a name to their own grades The best quality/graded crystals dont generally need AR...for example AP crystals are amazingly clear so are RMs ...on most of there range In looking at the crsytal you look at shape, fit and opacity and clarity and refraction in light both natural and artificial.. AR too varies....quality and strength, application and method, etc etc....a strong quality AR can easily be placed both sides however tool watches or lower grade AR should be internal.... Gen AR varies because of different suppliers, different models or years etc etc...you can get a blue hue AR on a PAM one year and that same model could have a grey hue the following year..etc..Some gen brands have 'trademark' AR hues to thier crystals like Breitling... You need to decide if you are trying to replicate a gen AR or just want the best AR you can get.... once you decided you can chose your source for AR.... its not just about hue...its also about the strength of the AR in terms of light refraction and also in terms of being worn and used... the hue is only one consideration.. There are many guys on the forum who offer AR...you would need to research them individually and chose based on what you want... It also matters on the type and quality of crystal being ARd.... some cheaper lower grade crystals will react differently after coating to that of a higher grade...so you can have 2 crystals of different qualities that get the same coating at the same time and look different under lighting or against the dial...indeed even the dial and its markers or lume can effect the look of the AR...say you get an AR with a greeny hue.... it may be very slight on a white dial but on a black dial it will look stronger add to that a greeny lume on the dial that slight greeny hue on the AR will look even stronger...the variations go on and on... and only specific questions can be answered on that... there is no general answer Crystal sapphire types go on and on ..just look at corundum etc Crystal shape and thickness always makes a difference...and again it varies so much you would need to be more specific.... but look at say a DSSD that is 6 or 8mm thick...at angles its completely distorted...look at a PAM LM thats 3.5mm thick and distorts ...at angles and also lays concentric rings around it as you turn the angle.. Cyclops can be very useful again it depends on the size of the DW...in turn decided by the movement etc..or the design... then you have the AR, Crystal quality, dial style, etc etc..... cyclops can be very helpful and at the end of the day they are a buyers choice 1 Link to comment Share on other sites More sharing options...
fraggle42 Posted September 13, 2013 Report Share Posted September 13, 2013 > What is the best crystal you have ever looked through?I think it's my gen Breitling Aerospace, but soon I'll have a franken Omega PO with a gen dial and crystal and I'm hoping that'll blow my socks off. > What are the qualities you look for in crystal and why?It fits properly, has no flaws and is slightly domed. I like domed crystals as flat ones reflect more light - domed crystals "shrink" any overhead light sources making them look smaller. > AR coatings? Which coatings? Does both sides matter?Not bothered which one, so long as it is very, very AR. Both sides, yes. I suppose if you did a physical job you may want internal only as the external AR would get scratched and make the watch look bad. > Do you find crystal thickness makes a difference with clarity?Not enough experience of different watches to say, but I'm not one for mega thick crystals. > Close or far from the face?Too far from the face is just a waste of space - why make the watch even taller than it could be? Water resistance depth is one reason, but really, who needs more than 50m depth WR? > Is a cyclops just annoying? Not if it does its job well! Link to comment Share on other sites More sharing options...
EbolaVirus Posted September 13, 2013 Author Report Share Posted September 13, 2013 Wow!!! Thank you both for taking the time to give me such in depth answers!I am building a watch (obviously), but its not a rep. It's been in design stage for the last year while I've been tooling up.At this stage of the design the crystal is flat 3mm thick. I was intending on AR on both sides, but from what has been said maybe just internal would be better.Is there any coating i can put on the internal side of the crystal which will allow UV through from the environment but reflect any internal UV which has come through and bounced off the face? Link to comment Share on other sites More sharing options...
PeteM Posted September 13, 2013 Report Share Posted September 13, 2013 (edited) Wow!!! Thank you both for taking the time to give me such in depth answers! I am building a watch (obviously), but its not a rep. It's been in design stage for the last year while I've been tooling up. At this stage of the design the crystal is flat 3mm thick. I was intending on AR on both sides, but from what has been said maybe just internal would be better. Is there any coating i can put on the internal side of the crystal which will allow UV through from the environment but reflect any internal UV which has come through and bounced off the face? Removing UV under the crystal is best served by coating the dial.... most brands do it....of course it depends on the dial... but generally using a UV resistant lacquer would help.. this protects the dial and helps reduce those reflections... OP for example used a Zapon lacquer finish on thier galvinised dials...this can be bought in 2 pack applications and with various UV protective strengths But it comes down to the dial, its material and finish... If you go with someone like Domi's AR...his current AR coating is extremely durable and therefore good enough for a double sided coating and is very strong in refraction at all angles Domi can also provide a good lacquer as I gave him a load of professional grade UV lacquer to do some dials for me So he has plenty left over Edited September 13, 2013 by petem Link to comment Share on other sites More sharing options...
EbolaVirus Posted September 13, 2013 Author Report Share Posted September 13, 2013 I was thinking it may be nice to have more UV hitting the dial. Maximise lume... I didn't think about fading. Link to comment Share on other sites More sharing options...
PeteM Posted September 13, 2013 Report Share Posted September 13, 2013 (edited) I was thinking it may be nice to have more UV hitting the dial. Maximise lume... I didn't think about fading. In which case you can go with a gloss finish lacquer as above.... that would lift the dial... but the lume thats something different mate.... if you want that to lift then a different appraoch is needed..but as I said all depends on the dial itself... UV wont really lift lume... but TBH I am not sure what you are trying to achieve from your description... Edited September 13, 2013 by petem Link to comment Share on other sites More sharing options...
EbolaVirus Posted September 13, 2013 Author Report Share Posted September 13, 2013 I am not sure what you are trying to achieve from your description... My poor description... Effectively I would like the crystal to be a one way mirror only to the UV spectrum. I thought it may be useful for UV to be let in through the crystal to give the usual charge to the lume. Following that any wasted UV which did reflected off the face could then be reflected a second time off the crystal towards the face. Link to comment Share on other sites More sharing options...
fraggle42 Posted September 13, 2013 Report Share Posted September 13, 2013 Is there a transparent paint / coating that absorbs UV? If so then you could paint the dial in that prior to luming, and then lume it. That way the lume would be exposed to UV to gain any benefit from it's charging effects, and any UV hitting the rest of the dial would be absorbed and not reflect. Link to comment Share on other sites More sharing options...
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