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Featured I Renovated A Ducati 748 Temp Gauge...

Discussion in 'Builds & Projects' started by Dinozoiks, Sep 10, 2020.

  1. Had my 748 for 20 years now and am on my third temp gauge. I'm sure they are fine in the balmy summers of Rimini, but swings of -15ºC to +35ºC in the UK seem to put it through a few too many stress cycles. The latest temp gauge finally called it quits. I'd previously got quotes from gauge refurb places but they were up near £200. Knowing these gauges were like rocking horse poo, I decided to renovate it myself. Materials cost, about £3.50.

    Before:
    [​IMG]

    After:
    [​IMG]

    The process went something like this...
    1. Stick a sharp knife under the bezel (glued on) and "carefully" break it away, snapping the glue.
    2. Measure the old bezel with callipers, create a profile in Adobe Illustrator and then do a 360 sweep in TinkerCad to get the bezel shape.
    3. 3D print it (I have the cheap one from Aldi). Took a few goes but managed to get a decent result. I used PLA+ filament.
    4. Sand the raw print with 400 grit then 1000 grit wet and dry to smooth the 3d print lines. I considered using ABS filament and smoothing with acetone but it lacked precision.
    5. Prime it, spray it black and used a satin clear coat to match the original plastic finish
    6. Get a 10cm square of 2mm acrylic sheet (I used an off-cut of 2mm acrylic sheet from B&Q), place it on a small drinking glass and pop it in the oven until it starts to warp a little.
    7. Take it out and gently press the centre of the sheet with a old magnifying glass lens (to get the slight curve the original gauge lens had). Just 3-4mm is needed.
    8. Use a compass cutter to score the glass outer edge. Two tips: 1) cut the acrylic to size after the oven treatment as it shrinks slightly in the oven. 2) The compass obviously has a point which will leave a dot in the centre of the lens. I double-sided a 1p coin to the centre of the glass to protect it, then double-sided a small off-cut of acrylic to the top of that to give the point some grip. Then score the circle.
    9. Once the circle was scored a fair bit, carefully use a scalpel to deepen the circle scoring. Then use pliers to snap off the excess around the edge. Sand the edge to remove jags.
    10. Glueing the lens in took a few attempts to stop glue fouling the lens. In the end, I used epoxy around the very outer edge of the lens then popped it into the 3d printed bezel. This kept the glue a few mmm away from the visible lens join.
    11. Then epoxy the new bezel on the gauge.
    12. Done.
    Took a day or two end-to-end...
    • 3D print took about 2 hours
    • Sanding 20 mins
    • Spraying a few coats took a day to let it dry
    • Making the lens took 2 hours.
    • Assembly 10 mins

    If you're up for the challenge, the 3D bezel design is here... https://www.tinkercad.com/things/jm5lHuxz5tK-ducati-748916-temp-gauge-bezel

    I have another of the old (cracked) temp gauges I'm about to put through the same process so I'll update you if there's any difference. But hope that helps give you some ideas if you were as fed up as I was looking on forums and EBay for decent replacement gauges when I had a pile of them sat on a shelf.

    Some pics of some of the main parts of the process...
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    [​IMG]
     
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  2. Very nice job and very interesting. Well and worth knowing for future use. I have had a few gauge faces replaced in the past and that was done by just merely replacing the damaged bezel with one from a broken gauge where the bezel was good.
     
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  3. Fantastic write up and an ingenious solution.
     
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  4. Brilliant, love it.
     
  5. Great work that mate thanks for the write up, they are prone to fking up so great bit of info :upyeah:
     
  6. Great job there and great future knowledge to said problem and solution:upyeah:.
     
  7. Excellent work and great write up.Looks like new .
     
  8. @RickyX

    Thank you for the thread, you have the basis for a business right there, very impressive.
    Only comment I would make is, that you were fortunate the bezel came off fairly cleanly as the original adhesive applied often spreads to hidden contact areas inaccessible with a scalpel which increases the risk of the casing becoming damaged/fractured when removing.
    this was relevant when trying to save the bezel but now you have found a way to re-manufacture, the bezel could be carefully turned off on a lathe and/or broken away to preserve the casing in worst scenario.
     
    #8 Chris, Sep 10, 2020
    Last edited: Sep 10, 2020
  9. Indeed. I sensed that when it finally 'gave way'. Luckily the bezel covers about 5mm of the front face and the side overlap, so it has the potential to cover up all sorts of mild filing-based shenanigans. As you say, filing or lathing is preferable to accidentally putting a whacking big crack in the body but I guess it does come with the benefit of being dust-free. Risk / reward ratio. The lathe option intrigues me... if only I had a lathe. I've avoided getting one as everything in the house would end up round.
     
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  10. As Wayne noted, love your last comment! ^
     
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  11. Most useful, ta very much :upyeah:
     
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  12. One of the best things I've seen on here, and there's a lot of very good things over the years. Well done. :upyeah::upyeah::upyeah::upyeah::upyeah:
     
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  13. I sense you might not have the time on your hands, but if you were considering a batch of these and the larger diameter tacho/speedo - bezel plus "glass" then would place an order for two immediately. :upyeah:
     
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  14. This is an excellent piece of work IMO. I forwarded a link to a mate of mine who has a couple of 3d printers that he uses for all sorts of fabrications and repairs around the house. He was well impressed, and particularly liked the innovative approach to producing the domed perspex, which I whole heartedly agree with.

    I am not personally familiar with the original gauge, but do you think your repair will be more robust than the original?

    Graham
     
  15. @Chris the original glue is the same as the bond for the headlamp glass. It will come apart, but like the headlamp lens needs to see the wrong side of 200 degrees before it just peels off in your paws.
     
  16. yes, tried heat, tried the lot over the years, but no luck on some despite this.
     
  17. I tried to take a headlamp apart many years ago and I think it needed a heatsoak it in the oven for around ten minutes at 130 C.

    Mrs Sev was less than impressed.
     
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  18. You did a fine job there. Would you share the dimensions of the bezel you made. I want to do something similar but lack the 3D printer. I have however a cnc mill. A drawing would save me taking mine apart first.
     
  19. How exciting, which one do you have?
     
  20. It's a denford Nova Mill that was donated to me a couple of years ago. Quite small but capable enough if you have the time.
     
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