Hesalite crystal of Speedmasters
What is Hesalite : it is a brand name of a plexiglass , this is the material chosen by Omega to make the crystals of the Omega Speedmaster Professional. This was a logical choice in the end of the 50's but is it still a good material today ?
The Speedmaster Professional is available today with either the Hesalite crystal or Sapphire , Omega keeps the Hesalite version because lots of customers still prefer a watch as close a possible to the one approved by NASA.
I will try to expose here the advantages of the Hesalite crystal and explain how to polish off scratches on it.
One of the biggest advantages of the Hesalite crystal is its shock resistance, I have personnally tested its resistance on a Speedmaster Professional crystal I had as a spare part :
I have used a little watchmaker hammer to try to break the crystal : even if banged VERY strongly nothing happened to the crystal despite a real horrible noise ! I could not imagine performing such a test with the watch! the crystal then has been hit with a standard hammer ... and survived perfectly the test.
Any glass or sapphire crystal would have broken in such conditions : the Hesalite crystal of the Speedmaster is really shockproof
One of the real drawbacks of the Hesalite crystal is that it is subject to scratches , on the same crystal I have deeply scratched the surface using watchmaker twisers , the scratches are deep and VERY noticable : I never had so deep and horrible scratches wearing my Speedmaster
I will explain you here the process to remove enven the worse scratches on your crystals , the process might sound scary but works ! if you are working on the watch first of all protect all metallic pieces with scotch tape : the bezel is fragile on the Speedmaster and NEEDS to be protected
Then you will need to deeply depolish the surface of the crystal (only if you have deep scratches some hair thin scratches can be removed without going through this process)
I am using a grade 600 abrasive , normally used to prepare surfaces to be painted. This kind of abrasive can be found in any general store , of course, it needs to have thin grains : 600 or 1000 is perfect. For deep scratches the process might be quite long.
I highly recommend you to make this process using a a few drops of water on the abrasive : it will prevent overheating of the surface and smooth the polishing.
When the surface of your crystal is depolished, you can start the polishing process : you will find MANY different products to polish watch crystals : I have a personnal experience with 3 products : one of thoses is now discontinued so I'll not mention it.
I am using for this expenrience a product I have recently found : the "DISPLEX" , this product has been designed to remove scratches from the displays of mobile phones, it should be a product very easy to find either in mobile phone stores or on-line shopping.
The other similar product I have used before is the well known "POLYWATCH" which gave similar results.
Use only a little amount of the polishing compound like shown on the picture , then polish the crystal with a CLEAN cloth : it is VERY important that your polishing cloth is totally clean and has not been exposed to any dust , otherwise you can not obtain a perfectly polished surface
Polish the crystal applying a certain force on the crystal for a minimum time of 2 minutes , then check for any remaining scratches. If some deep scratches remain it means that your depolishing process was not deep enough : go back to previous step with the abrasive
If only small scratches remain simply repolish the surface with the polishing paste for about 2 minutes.
And that's it ! your crystal will look brand new !
I hope this little article on the Hesalite crystal has been helpfull to you
You can now feel a little less nervous about those Hesalite crystals which have a REAL interest for sport watches
Omega kept the Hesalite crystal on the Speedmaster Professional not only to respect the historical background of the watch but also for functionnal reasons
as usual and for legal issues a little disclaimer :
if you intend to do this polishing by yourself you do it at your own risk . The webmaster of this site declines all responsability in case you might make any damages to your watch doing this process