Mengus Watch Tech – Episode 5

Episode V – Water Resistance

Water resistancy can be grouped under two standards: ISO 2280 and ISO 6425. Most watches, if they are not a serious real diver, will not be tested and badged under ISO 2280 standards. The real water resistance can be provided if ISO 6425 standards are applied. EG: Water resistant 20 atm is different than “diver’s 20 atm”. First one is for snorkelling, the second is for scuba diving.

There is no “water proof” watch in the world. After some time or pressure, all watches have leakage. Underwater pressure is as 1 atm increase per 10 m depth. Enormous pressure is exposed on a watch at depth, this is usually measured in centimeter squared.

There are 3 weak points on watches when water resistancy is issue:

1)Crystal gasket (I ring, we mentioned at episode 4)



The domed thick crystals always have more resistance for depth pressure due their convex structure.

The thickness of the I ring is also important.

Applied locks and under crystal secondary gaskets always pays off.

The crowns have double or triple nitrile or vitron gasket “o rings”. They are quite resistant if not exposed to direct sun light. They can last more than 10 years.

HINT: If you are looking for a sport watch, field watch or diver watch, the crown must be of a “screw down” type. There’s no difference if it’s inner threaded or outer threaded, but inner threaded ones stay cleaner and the thread is not easily stripped out.

Backlids both screw or bolted, if they have proper vitron or nitrile ring gaskets, provide water resistancy. The screw downs are a bit risky, friction during screwing down the backlid may damage the gasket. It will be better to replace backlid gaskets after opening and closing it a few times. The gaskets are very cheap.

There is no need for water resistance over 5 atm for dress or pilot style watches, but they must be min 5 atm. For me, a watch must be 5 atm water resistant at least for every type or style.

You will see Helium escape valve on cases of 300m (30atm) and over divers watches. This is for saturation. When you come up to surface the pressure inside may pop up the crystal. This valve lets out the pressure. They may be manual too, as in Omega Seamaster PO at the 10 o’clock position.

HINT: Always wash your watch under fresh water after salty water contact. Never leave your watch within salty water. This may damage gaskets.

There is certain amount of athmospheric water particles in watches. This may cause fog on the crystal. It is normal, but you may get it dried when it’s serviced.

If you use your watch differently than the designated and marked water resistance standards eg: Using a 5 atm watch whilst diving, there will be leakage. The fog may appear ( if you are lucky, the watch will survive, and it will not fill with water)

The appearance of fog means there is a slight amount of damp air in the watch. I know, it looks nasty and irritating. It occurs when the crystal is cold and backlid is warm. It is kind a condensation on the surface.

Today there are lots of desk divers. People like them, buy them, wear them. Actually most don’t comply with ISO 6425. They’ve never really been tested. Never actually left under designated pressures. Most testing is simulated in the factory with a pressure testing device, that actually doesn’t involve water. Basically the pressure is changed in the chamber to the amount required (20atm for example) and it then senses if this drops. If it does, it means that some of the air has leaked into the watch. If it doesn’t, it means the watch can handle that pressure with air and since water is thicker than air, water therefore won’t leak in either. Some check for deformations at different pressures by being in contact with the crystal during the test. Most don’t test to more than 1.5atm pressure in reality…

Typical pressure testing machine

HINT: While choosing a diver watch, and if you would like to know if it will survive the indicated water pressures, be sure there is an indication of compatibility at their website, user manual etc. It will be better to search and buy a REAL ISO divers watch. I can not name a brand here, but there are really cool macro and micro brands that are actually meeting standards.

The rotating ring is not a must nowadays with it’s indications in 15 min increments. These bezels are made of ceramic mostly and look nice. It is a quick time keeper for divers both ascending and descending, to check air left at tanks etc. Be sure it is unidirectional and clean neat clicks 60,45 or 90 ….

Diver with ceramic bezel

For all movement type wrist watches there are 3 deadly enemies :


2)Magnetic fields


Many watches are broken down and serviced because of water leakage. Have you ever taken hot a hot shower with 3 atm water resistance watch left on your wrist? Probably it ended with disaster, or luckily nothing happened.

In reality, hot water causes metal and gaskets to expand and therefore compromises them. You should never really wear ANY watch in the bath or shower.

From many years ago, the voice of a 70 year old watch repairer of my youth, echos in my ears: “Nobody gets in water with a watch they love”

Nowadays there are diving computers, designed for the job and better suited. If it makes you happy, you may prefer to dive with your diver watch, as secondary time keeper. It is truth that, we mostly wear divers at pools and beach. Heck, most never dive in their watches, but it’s nice to know that they’ll survive washing the car at the weekend.

Here are some serious divers:

Mengus Watch Tech – Episode 4

Episode IV – Watch Crystals

If we can’t use the practical information in daily life, that we learn from reviews or articles, then what is the purpose of spending time reading them in the first place?

Lots of things are talked about in forums and FB groups about watch crystals. If it’s not sapphire, then it’s not worth having, according to many.

Here are the typically used materials in their scale of hardness:

  • Sapphire
  • Hardlex
  • Mineral
  • Acrylic
  • Polycarbonate

In reality the crystal material does not make too much of an effect on the watch you’re wearing, if you do not count price. It’s all about the benefits that particular crystal gives. By the end of this article, you will understand what I mean. The most expensive material in market is artificial sapphire crystal. The ranking is close to “8-9” at MOHS scale (a hardness scale for gems) very close to diamond. Yes, in all aspects, sapphire is very scratch resistant but not scratch proof. Realise the difference. You can scratch or shatter sapphire. It is hard but not impossible. Sometimes you see a beautiful blue tint in sapphire crystals. This is directly related to the quality and thickness of sapphire and the Anti Reflection Coating (applied layer on surface to prevent glare). This treatment prevents glares and reflections and increases legibility. You may hear of “Double Domed” crystals. This has nothing to do with the size, what it means is that the outside of the crystal is concave, whereas the underside is convex. This allows for less distortion, especially at depth.

HINT: Always chose internal AR coated sapphire crystals. Externally treated crystals will start to peel because of friction, and a very nasty looking appearance occurs on surface.

How do we know if a crystal is sapphire or not?

It is hard to prove if a crystal is sapphire or not. Jewellers and watch makers use special tester apparatus or needle apparatus. This is the same as used to detect if a diamond is real or fake.

HINT: You can ping the crystal with a steel or nail (try not to scratch it). If the sound is treble, it is probably acrylic or polycarbonate. It’s not a foolproof method because hardlex and mineral crystals also have strong bass sounds.

HINT: Another common way is dropping water on surface.

Water drop test. If a drop flattens on crystal, It is not sapphire. Probably acrylic or polycarbonate.

If the drop stays round and domed. Crystal is probably sapphire.

Best way to define sapphire or not is the tester pen apparatus however.

What about mineral crystals, acrylics and polycarbonates.?

Mineral crystals are quite durable. Mineral choice may decrease the price by USD 30 to 80 when you are choosing a watch. It is not possible to determine if a watch has a sapphire crystal or mineral crystal, simply by looking.

The crystals are fixed in case in 2 ways: Use an “ I ring” (made of nylon and holds crystal by friction) and UV glue. I ring gaskets may cause water leakage after time due deformation and if exposed natural abrasives like acid, base contact etc. UV glue is a kind of chemical that start to bond under UV light only and fixes the crystal in its nest.

A nice watch, called the Vostok Amphibia diver series, uses acrylic in a clever way. This watch is AK 47 of watches. It is a completely amazing design. The crystal is flexible because it’s made of acrylic but hard and thick enough to counter to 200 m (20 atm) pressure. Acrylic crystals becomes flatter when water pressure increases, and from the sides this squeezes and holds the I Ring tighter. The deeper the depth, the tighter it becomes. Besides, acrylic decreases the price tag of watch. Another incredible part of this watch is the backlid. A separate ring keeps the backlid rubbing and deforming the backlid gasket. We will cover water resistance issue in a separate episode. I Hope Tony will do a review one of these Vostok Amphibia soon. (Hmmm, I don’t like them as much as you do Mengu – Tony)

Any questions are welcomed. Any point in your mind, I will try to give an answer. Keep your watch crystal clean, till next episode!

Mengus Watch Tech – Episode 3

Wrist Candy

As you know, the total appearance of a watch can be changed on the wrist or on desk, by changing the strap. I am sure most of us are in need of a strap change sometimes, when it becomes old and worn or when sweat and water destroy it.

Buckles and clasps, for all rubber, leather, fabric  / cord straps, are best to be made of stainless steel. Alloys may cause allergic skin reaction.

In all conditions, I firstly look for a comfort level then appearance. I am a bit meticulous and restless when a watch can not find its balance on my wrist. Lets look more closer how to choose the straps, the features of each and hints:

For all straps, do not fix watch on your wrist too tight or too loose. Always leave a gap, just to push your watch up your wrist in case you need to wash your hands or you may need to reach to something dirty or sharp quickly.

As you will see all watches have lugs that curve downwards. Sometimes however, this angled structure doesn’t make the watch sit any better on the wrist.

If the watch is too big for your wrist or if your wrist is too thick for even 45-50 mm diameter watches, you’d be better of choosing a strap with curved end links, or curved end, these will fit the case snugly between the lugs .

(HINT) Be careful : Sometimes you can’t fit thin watches with curved straps. The lack of rotation on the springbars would make the watch rest strangely on your wrist.

STAINLESS STEEL BRACELETS : Always choose stainless steel. Alloys may cause skin allergic reactions. While choosing, we recommend bracelets that match with your case finish e.g. brushed case with brushed bracelet, sandblasted with sandblasted… Bracelets are best for dress, diver, sport style watches. Too thin bracelets are not durable and they are flimsy. (HINT) While choosing an aftermarket bracelet, shake the bracelet from side to side. If it fells loose or squeaks,the bracelet is low quality. You want it to feel solid, the thicker the links the better (at least 3mm) with flawless finish and a smooth clasp this is a decent quality bracelet. Always get professional help while adjusting the bracelet for your wrist, or at least get a link remover tool. These can be purchased cheaply off ebay..

There are usually 3 types of link. Cotter pins, which require a sharp object to push them out (look for the arrows on the underside of the bracelet which show you which way they pop out). Small screws, which can be removed with a small jewellers screwdriver. “Pin and collar”, these are removed like cotter pins, almost, but you have to make sure you don’t lose the collar.

The handicap of bracelets are, they are irritating cold at winter, but they are fine looking and durable.

In high grade diving bracelets, there a quick extension (ratchet) system integrated. This is so you can wear the watch over a wet suit without adjustment.

Maybe you fancy a mesh or stainless steel knitted bracelets? Here is a fine sample from 70’s :

LEATHER STRAPS: The most important part, is the leather genuine or artificial? (HINT) Easy testing. Smell the strap if it smells of leather it is ok but if you get plastic smell, probably the strap is made of PU and the leather is artificial. Do not trust what is embossed on backside of a strap nowadays, unless the strap is from a well known brand. Only choose “wax treated” or water resistant leathers straps if you will use watch everyday or at water sports. Regular genuine leather is not resistant to water. It deforms and will be compromised. The waxed and water resistant leather straps are bit pricey if compared regular genuine leather straps. Pay attention to the stitches. They must be clear, and wax treated thread.

You can get custom made leather straps. There are plenty of tailor made strap makers you can find in forums or watch groups. Do some research before you give them an order though. Choose “VAQUETA” leather at this time, where the leather is strong and tanned by using natural ingredients rather than chemicals.

Measure between the lugs to get the size of the strap. The size is usually embossed on the underside of the strap. The above photograph it is given “22” so it is compatible with 22 mm lug width case.

(HINT) Please pay attention to PU and Kevlar straps. I do not recommend kevlar straps. Kevlar dissolves to fibres when exposed to water, chemicals or sweat for a time. For some kind of PU straps or plastic derivatives, always try to choose ones that have genuine leather bonded on the wrist side:

RUBBER STRAP: Mostly silicone mixed rubber straps are fine for diving, tool and sport watches. They don’t go well with dress style, mature looking watches. The strap must not catch dust particles or must not be sticky. It must be medium soft and resilient but pristine. If you like softer, get ones with a high silicone percentage.

NATO-ZULU and NATO BAND: These are well known, durable, nylon/fabric/canvas bands. Designed first for soldiers and field purpose. Even if the band had been torn or damaged, they still stay on the watch. You can choose them from a wide range of colors and combinations. They are budget friendly. Using and changing them can be tricky the first time you try and fit one. (HINT) Here’s how to fix on watch in steps:

I think they’re the most comfortable straps ever, after curved neck rubber and leather straps. A Zulu band has oval rings (and usually more than NATO) and NATOs have rectangular rings.

Here is Nato-zulu sample on the wrist:

CORD /CANVAS STRAP and PERLON: If you want something comfy, but not nato or derivatives, then you can choose cord/canvas or perlon straps, all made of nylon fabric. These are fixed on watch like rubber or leather straps, only the material used is fabric. These are a nice option for hot and damp weather seasons and countries. Durable to sweat and very light, these permit air circulation beneath the strap.

Lately there has also been a rise in sailcloth straps. These are treated / waxed canvas which can repel water so are both comfortable and can be used in a variety of active situations.

If you seek comfort, you may prefer Nato-zulu, nato, cord/canvas and perlon.

Next leather, rubber and stainless steel bracelet with curved neck ends.

We recommend one more comfort plus option, which you can use with leather and rubber straps: Butterfly deployment clasps.

Butterfly deployment clasps flatten the buckle edges and reshape the strap to the contour of your wrist (please see below photo). You can use these with curved neck straps of all kinds except bracelets (they already should have a deployment clasp) to increase the comfort zone .

You can combine the matching colour straps with your watches matching the watch type and dial colour. It is up to your preference and taste.

Some micro brands looking cool with a nato band!

Stay punctual, stay comfy, stay cool…

Mengus’ Watch Tech – Episode 2

Watch Mechanisms and Practical Daily Tips

Welcome to our second horology edition at Watch Thoughts. Hope our articles are useful in daily life and while choosing your next watch. Today, in this episode, we will cover the watch mechanisms.

Mainly there are Automatic, Hand Wound, Quartz, Kinetic, Solar and Digital movements available on the market.

Let’s break them down:

An automatic watch is a mechanical watch that winds itself by your wrist motion (with a rotor, the half circle plate that turns if your watch has a see-through case-back). The mainspring is wound up and then released in a controlled manner by an escapement fork. This makes the main pinion turn and then watch then ticks.

Hand wound ones are like an automatic mechanism, but the difference is a lack of a rotor (winding weight). We do the winding by hand by turning the crown, the wind the mainspring. Some of automatic watches also allow hand winding. You can both hand wind and make it wind by wearing it, so the best of both worlds.

In a quartz watch a battery sends electricity to a quartz crystal through an electronic circuit. The quartz crystal oscillates (vibrates back and forth) at a precise frequency: exactly 32768 times each second. The circuit counts the number of vibrations and uses them to generate regular electric pulses, one per second. These pulses drive a small electric motor, turning gear wheels that spin the watches second, minute, and hour hands.

Kinetic mechanisms, by Seiko, work like quartz. But instead of a disposable battery like in quartz, they have a capacitor; a kind of rechargeable battery. The capacitor is charged by wrist movement spinning a rotor, like in an automatic watch.

Solar watch movements are also quartz based system with a capacitor but instead of being charged by a rotor, there are solar silicon panels on the dial side of main plate. The capacitor is charged by these panels.

Digital mechanisms are best represented by Casio. They are circuited systems, with battery or solar combined capacitors, and have a digital display. Liquid crystal is poured into segments on the display. These change when an electric current applied to them, from clear to black. There is a polarising filter applied on top. There is no moving or turning mechanical parts, no cogwheels in the system, only circuits and panels. Time is kept accurate by a quartz crystal.

Here are the pros and cons of each movement type:

I own most of the movements, and usually you choose a watch based on a particular type, depending on what you want to do with the watch.

If we return to automatic/hand wound watches, the biggest handicap of them are isochronism (accuracy). The basic reasons are : Magnetism (Do not expose your watch to magnetism,eg: Magnets, magnetic fields) Gravity (the biggest enemy) Shocks (dropping or impacts) Heat (do not expose your automatic and hand wound watch to below 0 or above 40 Celsius degrees or do not expose to sun for a long time)

Hint:: Try to keep your watch under your gloves if you plan to stay out in cold weather. The isochronism deviates because of the mechanisms metal components that shrink and lose their precision.

If your watch is too “ahead” or “behind” the current time like 30 secs or 5 min per day, you would need your watch to be serviced. The main reason probably is the magnetism. At services, the watch is demagnetised. For other “ahead” or “behind” issues like 15 sec per day or around, you can do a fine tuning by yourself.


To prevent the isochronism deviation or reduce it here are some tips :

Fine Tune / Regulate the Balance Wheel (Opening the caseback may cause your warranty to be voided. Please do not open the caseback for watches that are still under warranty. Watch Thoughts is not responsible for any damage if the tips are applied wrong)

You will need:

  • Proper backlid opener
  • Loupe
  • A toothpick or plastic needle

If your watch is running fast, then a very very small touch turn of the double punched (red arrow) lever to indicator “-“ side is what you need. If your watch is runnign slow, then again turn very very little towards the indicator side”+” . You can reach to +- 6/8 per day if your mechanism is well lubricated and clean. The temperature must be +20 Celsius while doing this.(68 F) The amount you have to turn the lever is not certain, it’s Trial / Error

Again, if you are accident prone or find yourself clumsy, never try to do this. Accidentally touching to balance wheel or spring and other components may damage movement.

Another way to do regulation is safer. As we have indicated previously that, the biggest enemy of automatic/hand wound watches is gravity. First you have to discover where your balance wheel is positioned. Then try this when you take your watch off, at home or before sleeping:

If your watch is ahead (fast) lay your watch as in figure 1. The balance wheel fork (pendulum will be in an even position, the gravitational force will be low) I do not guarantee to slow down your watch but it will reduce the chances of it going  faster when you’re not wearing it.

If your watch is behind (slow) then try to leave your watch as in figure 2. I will gain time  or at least will be close to current time:

There are tourbillion movements, invented to reduce the effect of gravity on movements. Tourbillon movements are running on a different axis and roatae to eliminate gravitational force. Unfortunately, even Chinese tourbillon movements are expensive due the very labour intensive manufacturing and needs expertise and craftsmanship.

I see frequently, especially on online sales sites, open heart watches are labelled “tourbillon” This is wrong. Open heart means, you can see the balance wheel through an aperture (window) on dial. You can buy at least 10 budget automatic open heart watches for the price of a basic Chinese tourbillon. Swiss tourbillons will break the bank. Please be careful, if someone is offering you a tourbillon below USD500. Probably it is not a tourbillon movement watch.

Quartz watches are always getting better. There are mecha quartz movements, giving the appearance of smooth sweeping second, by mating a mechanical chronograph module to a quartz timekeeping movement, i.e. the Seiko VK range. A nice option for quartz preference.

Another hint for your quartz watch: If you are fed up with bringing your watch to service for battery change every 2-3 years, try to pull the stem and hack /stop the watch if you are not using for long time. This will preserve the battery up to 70% and the battery will last longer…as long as it is kept in a dry environment.

Never keep your solar/light powered watch in your drawer or cupboard. Turn the face of watch towards a window when it’s not being worn. For kinetics, try to wear it for a couple of days now and then, at least every 2-3 months.

We are sure, that Slash is taking care of his Breitling Chronomat (with Valijoux 7750) with his vigorous strumming.

Have a nice TIME!


Mengus’ Watch Tech – Episode 1

Choosing Watches and Cases

I have spent a serious amount of time since 1990 on watch making and collecting.

In my recent past, I have been able to draw, apply and manufacture a couple of models. A lot of effort was needed, as well as a steady hand, eternal patience and nerves of steel.

I’d like to give you some insight into the manufacturing and design process, here on Watch Thoughts. I hope you don’t find it too technical and I’ll try and make it as zesty as I can. I Hope you will follow my article series, and I also hope you find the advice useful in making watch choices or in impacting the state of your collection.

In this episode we will cover the most important part of a wrist watch; its case. The watch character and durability is defined with cases. They house the “heart” of the watch; the movement, and keep them from damage. From whatever perspective you look at it, mechanical watch movements are delicate parts of watches and must be protected from impact, fluid, dust, extreme heat and cold. Many different materials and techniques are used to obtain cases ,but we will cover these later in the article.

Cases can be classified into roughly 8 types:

We see round and square shapes mostly in the horology world.

Wearing a watch is like wearing jewellery or clothes. There’s an unspoken “code” in our society as regards watches, just like a dress code or using the right cutlery at dinner. I’m not here to tell you what type of watch to wear at a certain occasion, you should always wear what makes you happy, but here’s my take on it anyway.

Watches can be classified usually due to their usage. On the whole they are “Sport”, “Dress”, “Tool / Field”, “Aviation” or “Diver”.

Lately, manufacturer,s both mainstream and micro, are creating hybrids of these types, where 2 or more styles are combined into one case. This is mostly fine, but  a diver in a dress watch style doesn’t make any sense. A 500m chunky case likely won’t go with your dark suit.

SPORT WATCHES: 38 mm or higher in size. Mostly chronograph. With all types of strap. Water resistance must be at least 5 ATM. Best examples: Tag Heuer Formula 1 or Tissot PRS 516

DRESS WATCHES: 38 to 42 mm in size. Minimal looking case and dial. Lume on hands and dial is optional. With all types of strap. Water resistance 3 ATM to 5 ATM is enough. Slim ones are more elegant. Best examples: Patek Philippe Calatrava, Franck Muller or Orient Bambino

TOOL/FIELD WATCHES 40 mm or up. Designed for a specific purpose or for calculating / converting units. Mostly combined with sport chronographs. The lume on hands and index must be strong. A legible dial is a must. Chronometer certificate and isochronism will be better for military usage. Water resistance must be at least 10 ATM. Best examples: Breitling Cosmonaute, IWC Pilot series, Rolex GMT

DIVER WATCHES  40 mm or up.mStrong lume on hands and index. Easy to read dial is must. At least 20 ATM water resistance is a must. Over 20 ATM, a Helium escape system will be suitable. Turning bezel with 15 min, in 1 min. increments is optional. (There are VDB diver models without turning bezel) Nowadays there are inner ring turning systems. Strap; rubber or Stainless steel advised. Stainless steel bracelet can have ratcheted extension system for wet suits. Stainless steel case or bronze (Marine grade bronze CuSn8 )  Best examples Blancpain Fifty Fathoms and Rolex Submariner.

It is obvious that, you will not wear your Orient Bambino or Omega De Ville while plumbing at home, diving or hunting… You could, but the usage of that watch is not suitable to the occasion. The flipside is, it is not recommended to wear a heavy chronograph (eg: Montblanc sport chronograph) or diver ( bronze CuSn8 1000 m with patina on it!!!)  with a tuxedo or  elegant dark suit. These would be more suitable with a casual stye.

You can divide, and wear your collection into 3 parts basically:

-Everyday (daily watches)

-Formal Stlye

-Casual Style

There are many different methods to obtain cases today: CNC , Mould and 3D metal printing.

3D printing is a very innovative way to obtain cases in small quantities.

Big brands like Rolex, Montblanc, Tissot are using the mould system. The case main body is obtained from metal blocks being pressed by a very heavy hydraulic press.

CNC is more conventional way of hand made or partially hand made watches. Drill, lathe and cutting methods have been used since  the early 1900s but computer aided design and manufacturing eased the process with 3 to 5 axis machines since beginning 2000s.

So what are the different case finishes?

Well, There are plenty of materials used to manufacture cases.

The most used ones are 316 L and 304 L type stainless steel.

If the weight is important for you, you can prefer Titanium (2 or 5 grade) watches.

Alloy type cases can be allergic on skin and poisonous, but for divers, bronze can be an option with stainless steel backlid. It is recommended to get CuSn8 marine grade bronze if you decide to buy a bronze diver.

Any epoxy or plastic cases are not in our range. I do not recommend these type. For example, Swatch has system 51, with full plastic monoblock case. If something goes wrong in automatic movement, it is impossible to open the case.

Concrete, aluminium and carbon fiber are new materials for watch making. A Carbon fiber case will start to “decompose” and  after some time period under sweat, water and extreme conditions, just like carbon fiber straps, which I do not recommend in any situation.

Concrete is weak for falling and impacts. Can be broken easily. Aluminium must be hardened, it is too soft for watch cases. As result, the best materials are stainless steel,titanium and bronze right now.

Surface finish options convenient on watch types classifications according to usage are:

Mirror shiny finish surface (dress)
Matte finish (dress, field, diver, tool)
Sandblasted (sport,dress)
Brushed (diver, sport, tool)
PVD/DLC treatment (sport,tool,diver) Looks black purplish or gold tones.

We recommend brushed surface watches for diver, sport and tool, as minor scratches can be disguised.

Mirror shiny finish is not suitable for divers, tool and sports watches.

Sandblasted surfaces can not cover scratches. Not recommended on diver or tool watches.

For dress watches, a brushed surface will be too crude. Not recommended.

PVD/DLC and ceramic treatment options are very nice surface hardening options. These give a more tactical-classy look to watches if you prefer a black color.

PVD AlTiN is black TiN  in gold tones. For ceramic, the color range is very wide.