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How to

Accelerated Patina – Ammonia Fuming

Here’s how to go about fuming:


  1. Remove strap and then remove buckle.
  2. Punch tiny holes through top of clear Tupperware container to line up with lugs.
  3. Push thin wire through lug holes and suspend watch upside down inside the Tupperware lid [before this, clean watch with acetone to degrease and wipe with cotton-wool [refer to my photographs!].
  4. Pour about one inch of HOUSEHOLD SCRUBBS AMMONIA into container. Do not get ammonia directly on watch head. DO NOT use industrial strength ammonia.
  5. Snap top with watch in the container. Remember that ammonia is hazardous & poisonous. Do NOT do this in your kitchen, but rather in the garage or similar place.
  6. You can watch the watch change color – after about 15 minutes. Leave in until you think it¹s the right color. There’s no ‘correct’ time frame – just go with your instinct and what you are seeing.
  7. If it gets too dark, wipe with cotton wool with pure lemon juice and it removes patina IMMEDIATELY. So wipe, rinse in soapy water bath with toothbrush.
  8. Place back in container. I keep doing this until I get the effect I want.
  9. A lemon juice bath and LIGHT brush with toothbrush removes almost all patina – so you can start over.
  10. The maximum time I have kept a Bangla in is about 20 minutes – on and off.
  11. There is NO stabilization required.
  12. Patina can be lightly lightened with toothpaste and toothbrush – but go slowly.
  13. You can ‘hold-back’ areas if you want to by ‘masking’ with Vaseline – but afterwards, rigorous degreasing is required with acetone [acetone does not damage brass or sapphire].
  14. Shiny areas can be achieved by lightly wiping areas with finest steel wool that MUST be soaked in engine oil to limit the aggression.
  15. After a few watches the ammonia does seem to lose some of its strength so replace with fresh.
  16. After the patina watch has had time to ‘rest’ if you put it back in fumes, it will darken certain areas only – giving the head an antique look.
  17. As mentioned – if it goes too far – bathe/soak the head in lemon juice, then wash well in soapy water, degrease in acetone, start over ONLY when the watch is completely dry.
  18. Important – TURN the crown occasionally so that it gets fumed ‘fully’.
  19. You may get ‘blue’ patina build-up around inside of crown – I pull crown and clean with a bit of leather and thin cord.
  20. For soapy water I use good brand of household dishwashing liquid.


That’s about it!



  1. If you are wiring through lugs, be careful not to scratch the case; you could ruin a beautiful patina.
  2. Your brass case should start to change colour in 15 minutes or so but it can take anything from 25 minutes to 2 hours to gain decent colour.C. Take the watch out of the fumes every 15 minutes or so not only to monitor the colour but also to make sure there are no problems like blotches forming, etc. If so, just rub down with cloth, de-grease and place back in fumes.D. The objective is to patina the watch, not to gain even colour, so if it looks a little patchy don’t worry, this will mellow down with time in the tank.E. The Bangla was fumed with the bezel attached so as to achieve a more uniform overall patina.F. If the watch ends up too dark, do not panic! It can be lightened with a light speedy wipe with pure store-bought lemon juice, washed immediately in soapy water and dried very well before returning it back in the fumes.G. The process described here works for both brass and bronze watch cases. To quote Tony: “Ammonia fuming works so fast on brass … slower on bronze, but same great results”.



These guidelines were written by Tony Connell. Mathias Heller facilitated the gathering of information. Thank you Tony and Mathias. Diver’s Watches Facebook Group, its administrators, moderators and members take no responsibility for any results. You can try this only if you want to and with the results being your own responsibility.

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