# Bostok /Vostok?



## Deco (Feb 15, 2011)

I picked this up in an antique junk shop a few months ago and a dose of Polywatch did a decent job of cleaning the acrylic. The innovative case design which gives these watches their excellent water proof qualities is just one of the reasons I like to keep a two o'clock crown version in my small collection despite rarely wearing them. Despite the crack in the acrylic, the watch is waterproof to my low requirements.

I wouldn't mind if one of the experts on here offered any information or opinions on this one as I bought it with no information regarding model/age.

This is an extract from Wikipedia describing the original thinking behind the (often underated) design:

The Amphibia's crystal is 3mm thick lucite (50% thicker than standard) that is ground like a precision lens to create a very good size and seal. The lucite deforms plasticity by a half millimeter under pressure whereas the slightest deformation of a glass or sapphire crystal would crack it. This allows a much lighter, smaller, cheaper crystal to be used. It also does not require the extra rubber seals and a very high pressure crystal retaining ring.

While a traditional caseback gasket would experience shear forces with the rotation of a screwback case used for a traditional hermetic case that would leave the gasket permanently compressed, making it unable to return to its original shape and unsuitable for reuse, the Amphibia uses a very wide sintered gasket. This solved a problem found during the design where when surfacing, the gasket which had been compressed by 20-30% decompressed slower than the pressure on the caseback, critically weakening the seal. To fix the problem of the O-Ring shear, they used a bayonet mount held in place by a nut. This use of a very large gasket distributes the force of the pressure which can be a problem with O-rings.


----------



## NOTSHARP (May 2, 2018)

The watch will not be waterproof, with the crack in the crystal.

At all.

IMO, of course. 

Your watch isn't an Amphibia, but an older Komandirskie, which is not as "waterproof", to start with. I suggest that you have the crystal replaced, along with the stem tube, and caseback gaskets.

Well worth spending a few beer tokens on. :thumbsup:

Steve.


----------



## ry ry (Nov 25, 2018)

I love and hate my amphibia in equal measure.

It's fun and quirky, but the date adjust is pure pain, and the crown is horrific in every way. According to some test on another forum it got to 800m before detonation too which is useful if I drop it into the Mariana trench whilst on my way to work!

Replaced the strap and bezel, but I like the scuba dude dial & bean-can hands so they're staying


----------



## WRENCH (Jun 20, 2016)

ry ry said:


> he﻿﻿﻿ cr﻿o﻿w﻿n i﻿s ﻿h﻿or﻿r﻿﻿ific﻿ ﻿in﻿﻿ e﻿v﻿e﻿ry﻿ wa﻿y.


 There is a design reason for that crown, which works rather well.


----------



## ry ry (Nov 25, 2018)

I mean the finish of the crown, the antishock is cool, but its huge and sharp & savages the back of my hand!

I'd replace it, but I'd probably **** the seals up in the process and ruin it washing my hands.


----------



## NOTSHARP (May 2, 2018)

ry ry said:


> I mean the finish of the crown, the antishock is cool, but its huge and sharp & savages the back of my hand!
> 
> I'd replace it, but I'd probably **** the seals up in the process and ruin it washing my hands.


 Five minute, easy peasy, job to swap the crown/stem. :thumbsup:

Steve.


----------



## ry ry (Nov 25, 2018)

NOTSHARP said:


> Five minute, easy peasy, job to swap the crown/stem. :thumbsup:
> 
> Steve.


 Sadly I lack your Vostok modding skills. I broke a stretchy bracelet trying to remove it recently.

(integrated pins, I somehow flipped them out of their bracket and they got stuck, cut it off with tin snips in frustration!)


----------



## WRENCH (Jun 20, 2016)

ry ry said:


> I mean the finish of the crown, the antishock is cool, but its huge and sharp & savages the back of my hand!
> 
> I'd replace it, but I'd probably **** the seals up in the process and ruin it washing my hands.


 The new improved crown is much improved.










And even I managed to replace one. The Vostok is like an old Lister diesel, very forgiving to work on.


----------



## Deco (Feb 15, 2011)

NOTSHARP said:


> The watch will not be waterproof, with the crack in the crystal.
> 
> At all.
> 
> ...


 Thanks Steve.

I knew it wasn't an Amphibia, but wasn't sure if it was a Komandirskie, so thanks for the confirmation. I did think that both watches had similar waterproofing though, ah well.

Dec


----------



## NOTSHARP (May 2, 2018)

Deco said:


> Thanks Steve.
> 
> I knew it wasn't an Amphibia, but wasn't sure if it was a Komandirskie, so thanks for the confirmation. I did think that both watches had similar waterproofing though, ah well.
> 
> Dec


 Dec,

The problem is, it does not matter if it is a Kom or an Amp. The crack in the crystal will not withstand one atmosphere of pressure. There will, already, be moisture in the movement.

If you like the watch, get a new crystal installed, and replace the case/crown gaskets. Depending on its age/condition, it will be desperate for a clean and oil.

You may struggle to find a Kom crystal, although there are some around. The Amp crystal should fit, but it is a higher.

Steve.


----------

