Spoiler Alert: FOIS sapphire crystal can be exchanged with hesalite (plastic) crystal without any modifications at all to the watch. My FOIS proves it.

I purchased a FOIS Speedmaster with an original Omega 57 3594.50 dial exchanged. I loved the FOIS fit on my 7" wrist. I found the FOIS to be nearly perfect. Except for the milky ringed relatively flat sapphire crystal. Many articles suggest switching to a Speedy Professional for the more traditional hesalite crystal. I considered doing the same.

Then I found the Omega Forums. I've read several posts debating whether the FOIS' sapphire crystal can be replaced with a hesalite crystal. All the older posts insisted that this switch is impossible without watch modification, and that the resulting FOIS would not be waterproof or even water resistant. Thanks of Omega Forum, several members directed to watchmaker Lewis Watch Company of Australia, who described his vast experience swapping the sapphire Crystal for hesalite crystal. Lewis Watch Company website and Instagram displayed these modified FOIS, and seemed very convincing. The biggest problem is that Lewis Watch is in Australia; I was hoping for a watchmaker here in the United States that could also do the job.

After debating about sending my watch to Australia for the crystal swap, I searched to find a watchmaker in the US that could do the same job. I was lucky enough to find the watchmaker at Clock Doctor in Scottsdale, that had successfully completed this same hesalite for sapphire swap. Two before pics with sapphire crystal are below.





My hesalite crystal FOIS Speedmaster was successfully pressure tested to+6.0 bar without any problems. The improvement in my FOIS aesthetics and character once switched to hesalite crystal is simply unbelievable. Words cannot describe this enhancement. I love it!!!

The watchmaker said that the hesalite swap is completely reversible without any modifications required. He said it would take a day to swap it back to sapphire crystal if desired. I went with an original Omega Speedmaster crystal. The watchmaker insisted that the key to the swap was making sure the proper gasket was used. He said that a metal tension ring could be ordered but was not required to make the swap work; I opted to keep it simple.
t
All I know is that the final result is simply gorgeous and exactly what I was hoping for. The milky white ring is gone, and the original Omega domed crystal is a return to the normal character of a Speedmaster. In fact, this improved FOIS is more than I was hoping for and I can't stop wearing it. After photos with hesalite plastic crystal are below.

Thank you again Omega Forums for helping me find my way to my perfect Speedmaster.

 

Forgot to include the test shot. It passed easily according to this watchmaker.

 

Looks great! I may need to reach out to the Clock Doctor myself. Out of curiosity, how long was it before you had your watch back?

Now to find a 3594.50 dial….

 

Looks miles better than the sapphire, good work

 

That looks great! Do you have more infos what is needed? Parts etc.?

 

I dropped my FOIS off during Spring Training vacation. They said they could finish in a few days if I was okay using a generic Omega spec hesalite replacement crystal, which they had in stock. But I wanted to swap with a genuine Omega crystal. So that took a few weeks on order. Once they noticed me that the Omega crystal had arrived, the watch was done and ready for shipping a few days later.

 

I don't know the part numbers or any of the details like that. I just know that the watchmaker ordered the genuine acrylic Omega crystal, which didnt take long since they are authorized Omega. He also ordered a new replacement gasket because he said it's better to change the gasket just to be on the safe side. Also, the gasket is just a few dollars, so it's generally a good idea to use a fresh one.

I have the original sapphire crystal and gasket just in case I want to change it back from plexiglass, which I will not. But I guess if I sell this FOIS, I have the original parts for that case. I also have the original dial. I have read that the 3594.50 dials used to be easily purchased from ADs, but now are no longer available. I would double check that.

 

It was fortunate you found someone in the US to do the work because Adam Lewis in Perth does not modify customer watches, he states that specifically on his website. So you could not have sent your watch to him to have the work done.

 

Yes my FOIS also has this mod (with tension ring) without needing anything changed to the case. It was done by Lewis Watch Company and I got the original sapphire with it and can convert it back no problem if I wanted (I won't though as I much prefer it with hesalite). Thanks for the contact on a US based maker as I rather not send mine back to Australia if needed.

 

I also did a few mods to my FOIS.
There is basically hardly anything from the original the only thing i actually didnt dare to do was the crystal. As i believe that one has to slightly change the size od the hesalit crystal.
In day to day wear i actually find sapphire crystal very handy, no worry about scratches and the dial looks allways crystal clear. While i am really tempted to try the mod, i am not sure its really worth it. To be honest, i never really see the white ring that everyone keeps talking about.
First stage:


Second stage (current state) EdWhite

 

Great looking mods here. It does make me wonder whether the FOIS would have the same status as the Silver Snoopy 45th/50th amongst collectors if Omega had used that those features from the beginning, giving a truer recreation of the CK2998.

 

Well since the both those Snoopys have sapphire crystals I can’t see that the crystal is the biggest drawback based on that logic. It would have been a truer recreation of the Ed White perhaps with the features above but Omega have done that, and charged 3x as much as the FOIS.

 

Way cool for sure. Your FOIS is amazing.

The dial swap is the ultimate for a vintage Speedy look. I think an acrylic crystal swap would make for the ultimate vintage vibe, but it's clearly a personal choice.

 

Hesalite for front and sapphire at the back. Favorite straight-lug Speedmaster Omega has never officially made. The sapphire back makes it a joy to wear.

 

Show us the front please. I want to see the plastic crystal

 

here it is!

 

Your FOIS looks really cool with the tension ring. I kinda want one.

I know that early 2998s had the tension ring. You've got the 1962 looking bezel too. Outstanding final product. VERY NICE.

My watchmaker offered to use a tension ring, but said he had not used them for these FOIS crystal swaps in the past. Maybe I should let him place one for the aesthetics because man it looks sweet.

 

Nicely done!

 

The mods look great, but personally I wish they'd sold the FOIS with a stepped dial, DON bezel, a thicker crown, and a flat link bracelet.

I considered getting one before I eventually got my speedy, but I thought the crown was too thin. I don't know why they changed it, the thick crown on the original watch made it look much better.

The reason the Ed White is over double the price of a normal speedmaster is because of the 321 movement. I'm not too bothered about the movement, but I would have gotten a FOIS if they'd given it the same size of crown as as the 3861 speedmaster.