Ageing of Plastic Parts – SKZ227 Mapmeter

Saw this piece of well-worn Seiko Mapmeter SKZ227 at the watchmaker’s shop recently. The black plastic parts on both sides of the watch are not ageing well. They are broken and some parts had fallen off the watch.

If I remember correctly, this model was released in 2007 so I figure theses pictures are probably good indication of what the plastic parts would look like when worn regularly for 5 to 6 years (2007 to 2013). The first crack on the plastic probably appeared much earlier though.

From the pictures above, you can see that some parts of the plastic had fallen off and the parts that are still attached to the watch have attracted a bit of dirt.

Besides the Mapmeter, watches like the Franken Monster, Baby Tuna, etc come with similar plastic parts and collectors will face the same problem if they plan on holding on the these watches. There is no guarantee that parts for these entry level watches will be available several years down the road. One possible solution would be to buy spare plastic parts and store them in a cool dry place.

Here are some photos of a SKZ227 in happier times.

21 thoughts on “Ageing of Plastic Parts – SKZ227 Mapmeter

  1. Not just a cool dry place. If possible, a low oxygen environment, too. O2 kills rubber, elastomers and polymers with rubber components.


  2. any 3rd party came out with something like a aluminium shroud for this model? I changed mine just last 2 years after discovered the crack on the plastic. Did a full servicing at K2 as well.


    • I don’t think there is any 3rd party shroud for this model.
      You changed the plastic on your watch two years ago? You got the spare part from Thong Sia?


  3. i got the SRP236 and SRP453. I wonder if I should buy spare shroud and also the colored rubber strap for them. Since these are limited editions, how long will Seiko make the blue and brown straps and shroud?


    • I’m not sure since I don’t have these watches. However, I know some people have bought spare shrouds for their baby tunas. Don’t think you need to buy the rubber straps. You can always use aftermarket ones.


  4. Wow, that watch looks very sad and battered and worn to the limit! Do you by chance know the occupation the watch owner?
    Has it came into contact with kerosene, fuels, paint or paint thinner?

    I had worked at a factory helping out with spray painting, so I had to handle paint thinner and other chemicals that are ‘solvents’. These fumes and chemicals when in contact with the plastic parts also attack these parts, causing the same end result – cracks and fall off easily.

    Also previously, I used to store one particular watch with plactic parts in a drawer with nepthalyene balls (to rid of cockroaches and other vermins), these fumes attack the plastic parts and make them brittle, these crack and fall off easily.

    So be warned! Solvents (including fumes) attack plastic parts and prolonged exposure will cause these parts to be brittle and crack easily.


    • Thanks for the informative post, Ian. I don’t know what the owner works as but I’ll check with the watchmaker.

      Looks like these plastic parts are very sensitive to the environment. Beside those that you have mentioned, I think the heat from the sun and sweat on our wrist also play a part in breaking down the plastic. If I have these watches, I would rinse them under the tap after every use.


  5. I’ve been wearing a Frankenmonster religiously for several years now and have experienced much the same problems re: gradual degradation of the plastic shroud. Despite best efforts, I have been unable to source a replacement online. Much appreciated if anyone could offer a solution or suggestion …


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