Fixing an Otter switch?

Technical advice Q&A
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Dad
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#1 Fixing an Otter switch?

Post by Dad » Sun Mar 13, 2022 7:12 pm

As many of you will know, original Otter switches are hard to come by so now that my original unit from 68 isn’t working, I’d like to fix it. Trouble is, I effectively need to re-spot weld the bimetallic strip inside the stainless steel bulb back into its mounting pins (very mild corrosion has caused it to pop off, which is why it’s not working anymore). It would be an easy fix if I had a micro-spot welding tool (I’m sure such a thing exists but I don’t have one).

Any ideas? I’m even considering souring some extremely small brass screw and seeing if I can drill and screw it. Is there such a thing as electrically conductive glue? I can’t get it to solder.

Sounds a bit much, I know, but it’s worth it, imho…

Thanks,

Dad
1966 s1 FHC 4.2

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mxke
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#2 Re: Fixing an Otter switch?

Post by mxke » Sun Mar 13, 2022 8:43 pm

There are battery tab spot welders. Might work?
Mike
Mike - 1962 OTS 878380, 1965 Honda S600, 2001 Honda S2000

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mgcjag
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#3 Re: Fixing an Otter switch?

Post by mgcjag » Sun Mar 13, 2022 8:50 pm

Hi Dad....sounds odd....whats your name....try to put it in the signature area.....iv use this electrucsl 2 part epoxy...
https://uk.farnell.com/multicomp/mc0029 ... dp/2917615 sure you can get it or similar in Canada.....Steve
Steve
69 S2 2+2 (sold) ..Realm C type replica, 1960 xk150fhc

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david.coan
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#4 Re: Fixing an Otter switch?

Post by david.coan » Sun Mar 13, 2022 9:36 pm

I replaced mine with the one from Coolcat in USA.
https://www.coolcatcorp.com/Merchant5/m ... ry_Code=CS

Very happy, okay not stock but improved accuracy and hopefully reliable
David
1968 S1.5 OTS, ex USA converted to RHD

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Heuer
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#5 Re: Fixing an Otter switch?

Post by Heuer » Mon Mar 14, 2022 9:36 am

:yeahthat:
David Jones
S1 OTS OSB
1997 Porsche 911 Guards Red
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Series1 Stu
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#6 Re: Fixing an Otter switch?

Post by Series1 Stu » Mon Mar 14, 2022 11:43 am

Don't bother trying to repair the Otter switch, you will almost certainly affect the calibration of the bimetal while you have it apart (it might even be a trimetal). It might look the same but even small changes to the geometry will affect performance, especially if you are putting significant amounts of heat on it by spot welding. It's one of those things that need mending by replacement.

When new, the Otter switch was more than up to the job, although the early installation left a lot to be desired. Unfortunately they are now obsolete and definitely not repairable, so we need to find alternatives. The Coolcat alternative seems to be well tried and tested and is much recommended so why buck the trend?

Regards
Stuart

If you can't make it work, make it complicated!

'62 FHC - Nearing completion
'69 Daimler 420 Sovereign
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#7 Re: Fixing an Otter switch?

Post by Dad » Mon Nov 14, 2022 7:01 pm

Sorry for the really late reply! Busy year, etc. Thanks so much to everyone that offered advice; most helpful. Problem now fixed.

Dad
1966 s1 FHC 4.2

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Allrand
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#8 Re: Fixing an Otter switch?

Post by Allrand » Tue Nov 15, 2022 6:54 am

Tell us how you fixed it.
Randall Botha
'64 3.8 fhc & '51 Mk 7 (now sold)

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#9 Re: Fixing an Otter switch?

Post by Dad » Tue Nov 15, 2022 10:10 pm

I tracked down a genuine replacement but didn’t have enough kidneys to sell to pay for it so until that day I opted for a comparatively cheap replica from Moss. I’m also considering the Cool Cat option as it also doesn’t require a lottery ticket.
1966 s1 FHC 4.2

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#10 Re: Fixing an Otter switch?

Post by Heuer » Tue Nov 15, 2022 10:13 pm

Coolcat version is accurate and reliable as it is a Mitsubishi sensor in a bespoke housing. If it does fail (unlikely) replacements are easy to source.
David Jones
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helge.kassel
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#11 Re: Fixing an Otter switch?

Post by helge.kassel » Wed Feb 08, 2023 6:35 pm

Fosseway also offers a replacement for the otter-switch.
Not original style, but why shouldn`t we use better parts today?
I mounted this in my series 3 and it works fine.
Helge Kassel
If You do it, do it right
1971 V12 Aut 2+2 with MX5 Seats :bigrin:

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