[SML] S4 bench focus...

[Dorian Kelly]

I put a rig in a sea life centre, a really salty  atmosphere.  I remember having to replace luminaries - easier and cheaper than replacing all the corroded and damaged parts - practically bi-monthly. The old units were passed on to a local am-dram who were very pleased with them  even in that condition after they had replaced bits. God knows what the salt would do to a source 4 led2


> On 25 Jun 2015, at 19:02, e-mail frank.wood95 via Stagecraft <stagecraft at theatrical.net> wrote:
> 
> Bi-metallic reactions take place only in the presence of an
> electrolyte liquid. I like to think that such liquids woild be absent
> from a lighting rig. The sacrificial magnesium anodes fitted to
> sea-going craft provide a more attractive home for the electrons,
> being eaten away in the process of protecting the steel, brass, and
> bronze components immersed in sea-water.
> 
> What you should try is the copper-graphite gunge sold as anti-seize
> compound for soldering iron bits. I have found this very effective on
> shutters and iris diaphragms in vaious luminaires. Soldering irons get
> much hotter (I hope!) than any part of a luminaire.
> 
> On 25 June 2015 at 14:44, Steven Hood via Stagecraft
> <stagecraft at theatrical.net> wrote:
>> The bimetal reaction was the other thing I thought of, but I was wondering
>> why it was only happening in the 36 degree fixtures... my manufacturing
>> professors warned me about that...
>> 
>> Steven R Hood
>> 310.756.3555
>> 
>> 
>> 
>> 
>> On June 24, 2015 7:44:24 PM Dale Farmer via Stagecraft
>> <stagecraft at theatrical.net> wrote:
>> 
>>> On 6/24/2015 6:21 PM, Steven Hood via Stagecraft wrote:
>>>> Lighting folks,
>>>> 
>>>> Have any of you had an issue with the outer (XY) knob/nut seizing the
>>>> aluminum hub casting? We have... I've had to drill out 3 of them this
>>>> year - all from units that had been assigned 36 degree lenses. It seems
>>>> like that hub casting is heating up more from having to pull the Z
>>>> adjustment so far into the reflector and seizing on the outer nut as a
>>>> result. Is there some way to prevent that deformation?
>>>> 
>>>> TIA,
>>>> Steven R. Hood
>>>> 
>>>> 
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>>>> 
>>> It happens.  The only way to prevent it is to go in and unscrew the
>>> thing a couple of turns and retighten it every so often.  I've
>>> experimented with various high temp lube compounds, but haven't really
>>> gotten results yet.   My confidence is not high there is a reasonable
>>> solution.  It's bimetal corrosion between a steel nut and an aluminum (I
>>> think) casting.  So short of putting a magnesium sacrifical anode
>>> someplace on the light, that's not something you can stop.  (By the way,
>>> if anyone has a source of magnesium that is in the form of standard
>>> sized washers or nuts, I do have some gear that I do want to provide
>>> some sacrifical anodes on, but the only thing I have found is boat
>>> propeller nuts, which are way too large.  )
>>> 
>>> If you have one that is seized up, and you have a couple of days, you
>>> can take a q-tip and apply some penetrating oil to the threads and let
>>> it sit and soak in, giving it a good hard attempt to unscrew it twice a
>>> day, and adding more penetrating oil after each failure.    Don't forget
>>> to degrease it well once you have it apart, or you are gonna get some
>>> nasty smells from it the first time it is used.
>>> 
>>>   Or you can buy the replacement casting and a replacement plastic
>>> ring, because the plastic ring around the outside of the nut also gets
>>> broken when you put the big pliers on to unscrew it.  Which one depends
>>> on how much you are paying for parts and labor and how many spare lamp
>>> caps you have on hand.
>>> 
>>> --Dale
>>> 
>>> 
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>> 
>> 
>> 
>> 
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> 
> 
> 
> -- 
> Frank Wood
> 
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