Hi,

Is there a difference between Hesalite and acrylic?

TIA!

 

A simple Google search....
While not as hard as glass and therefore less scratch resistant, acrylic offers twice the resistance to fracturing—and any light marks can simply be polished out. ... Acrylic comes under a multitude of a trademarks, including Plexiglass, Perspex and, of course, Hesalite.

 

Thanks - I should have qualified my answer. I did search online a bit before asking. But it’s not like searching grades of steel. There’s not much information out there aside from Wikipedia and broadly speaking blogs. If Hesalite is just acrylic, I’m wondering if acrylic has different grades Like steel or other metals.

 

I don't think you will find different defined grades as you would in steel, at least not grades assigned by an international standards body like ASTM, AISI/SAE, or something like that. Note that even steel grades are not all perfectly defined as they have ranges for various ingredients so if you want to know an exact chemical composition you have to get a heat by heat analysis if you really want the details. But for acryclics there are various additives that can be added to acrylic to give it different properties.

I really don't know what is at the heart of your question, but Hesalite (Hésalite) is a trade name of Hesa AG, which is the Swiss company that initially made these crystals.

I'm not sure that is who makes Omega's crystals now, so I see it more like generic name for acrylic that everyone (in particular Speedmaster fans) uses. Just like Plexiglas is trade name of Arkema, but it has been turned into a more generic name by miss-spelling to plexiglass...Kleenex now means any facial tissue, etc.

I looked up a crystal for someone earlier today, and this is the full description:

063PZ5105 | GLASS PLEXI ST RING D31.12 H5.35

Omega just calls it plexi...

Cheers, Al

 

I believe there might be different thicknesses and heat ratings but for the watch industry, hesalite, a name originally used by Omega for essentially acrylic or plexiglass (a brand name), is a generic acrylic similar to what you see is Rolex and other earlier watches (not to be confused with mineral crystal)

 

The heart of the question is this:
- When someone purchases a acrylic crystal be it Omega, Rolex, OEM, or aftermarket (shape and dimensions aside) are they the same? Are they all acrylic? Or are there different "grades" of acrylic?
I see mention of standard and high-optic. I also see mention of additives. But that only partially answers my question. I'm interested in know if an aftermarket, acrylic crystal could ever be the same as an Omega, Rolex, etc. Or are Omega and Rolex (and their previous suppliers) using proprietary chemical compounds and additives to transform basic acrylic into something more special.

 

To me it's a question that is virtually unanswerable in the way you are putting it. As I've already stated, there is no grading system than is universally used, but there are likely things different manufacturers do for their own purposes. Some could be related to quality, but could also be related to solving a production issue - better productivity, longer tooling life, etc.. So differences in material compositions don't necessarily translate to end user quality differences.

The only way to know this is to find the suppliers for all these crystals, and find out the exact chemical composition of each, and then translate that into possible different physical properties that make up the definition of "more special" in your view.

In practical terms, having installed thousands of acrylic crystals off all different types, sizes, shapes, and from different suppliers, there's really no significant difference between them. There is no specific brand that watchmakers talk of avoiding, or conversely talk of preferring.

By my question still stands, what is at the heart of this question? Why does this matter specifically to you?

 

Aha! That's what you're asking.
Well, I just replaced the crystal in my Rolex 5512. I opted to purchase a G-S PA462-67 as I like the profile, the clarity, and it creates a water resistant seal with my retaining ring. I could have spent a significant amount more to purchase a NOS genuine or a fair bit more on some of the highly priced aftermarket ones. Don't even get me started if I opted on a superdome (Rolex or aftermarket).
I'm (mostly) happy with my decision but pose the question here because I cannot help but wonder if maybe I should have ponied up the extra money because Rolex or some of the high-priced aftermarket crystal brands are using some special ingredient to make the plexi incrementally more special.
Which leads to the other alternative. Are these other options charging a significant mark up on a $5 piece of plastic to cover their marketing and "R&D"? In the case of Rolex, it's really just a piece of plastic. Unlike Omega, there is not branding on the crystal.

 

Okay this helps. Note that there is more to a crystal than just physical properties of the material, which is what you have been asking about. Shape, thickness, sizing, tolerances - all of these things go into making a "good" crystal compared to a "bad" crystal. Often with Rolex, the complaint will be that the aftermarket crystal doesn't fit properly, which is not related to material properties that you have been focused on. The shape might not be 100% on an aftermarket "top hat" compared to an original, or the top surface of the crystal might not be as thick, etc. Also, some aftermarket crystals have been known to be too thick on the side walls, not allowing the ring to go over properly (cracking the crystal on installation), and have even thought to be "stretching" the bezels.

For Omega crystals, they have the logo but also often use specifically cut tension rings that aftermarket crystals don't use, so this has real implications of the fit of the crystal and the assembly of the entire watch.

As I posted above:

The only way to know this is to find the suppliers for all these crystals, and find out the exact chemical composition of each, and then translate that into possible different physical properties that make up the definition of "more special" in your view.

I can't speak to what these cost and what the mark-up is. There's a lot that goes into pricing an item for sale, and in the case of Omega I'm just happy they still supply crystals for watches that are from the 40's and on up. That doesn't mean that I was happy when the suddenly tripled the price of them all overnight...but it is what is is.