Cleaning Conventional Fixtures


Active Member
Thought this might be a good topic:

What chemicals do you use to clean convetional fixtures and anything special you do to clean them?

What kind of paint do you use to do touch ups?
Our fixtures don't often get that kind of care. Their electrics get checked out regularly, but it has been forever since I've seen anyone cleaning the lenses or reflectors.

It's probably a good way to enhance optical efficiency, though. The less dust and grime there is to absorb the light, the more of it gets to the stage. And of course, the less dry dust that is near the lamp, the lower the risk of fire.

Of course, we clean our lamps with mineral spirits whenever anyone thinks they may have touched one. I've actually gotten in the habit of doing that whenever I take a lamp out of the box if the mineral spirits are handy, because I'm neurotic like that.

We don't ever paint our instruments. We acquired a few of our stock from a local community theatre that was disbanding and liquidating their assets, and those 6x9s still say "TDT" on them (Something Durham Theatre). It would take a few seconds with some black paint, but we don't care that much.
I also do not clean my conventional fixtures. If there is a cob web in the light then i'll get it out, but besides that I just leave them. I follow the 'if it ain't broke, don't fix it' idea.
We havent' cleaned our fixtures in years and we really should. I'm thinking about doing a cleaning before the fall play.
when there is down time (read once a year max ) and the air compeser is on stage I might feel the need to bring in the eectrics and blow out all the fixtures. Cat walk lights neve get cleaned and intells get it once or twice a show. with same method
All glass and reflectors are washed down and wiped with isopropyl alcohol and a lint free cloth. Nothing worse that having bits of fluff stuck to things.

Any external painted surface is wiped down with a damp cloth and any touch-ups done with flat black spray paint or paint pen on painted fixtures, and with a paint pen on powder coated fixtures (just to prevent rust until there is a need to have the unit re powder coated).

Rusted bolts/nuts/washers are replaced (never throw a rusty (or even partially rusty) item into a container with new or good contrition ones as it will cause them to rust also).

I grease up any slides or runners with HTB grease. This is probably not the best grease to use and I am looking into other options for this.

Badly damaged fixtures or ones that I rescue from the scrap heap will get a thorough strip down and clean. They will then get either a new coat of paint (generally flat black, as touch ups are easier on flat or matt paints) or powder coated.

With the exception of an item that requires a lamp change or develops a fault or is damaged, all my lights are serviced and cleaned every 12 months and usually get a minimal wipe over before being picked for a show.

Keep in mind that I run a mobile/hire service, so my lights are packed up after every show, which makes it a lot easier for me to do this.
First off... those of you who dont clean your fixtures scare me. At LEAST every 12 months you should clean your all your fixtures and dimmers out. I started this topic to see what peoples response would be and I was shock on how many said they dont bother with it. Some reaons why you should clean your fixtures:

1. Optics
2. Fire Hazzard
3. Fixture Life
4. Physical apperance

Mayhem posted exactly what I was looking for. You should do maintance on your fixtures once a month and do a overhaul once a year. Always be checking connections, etc. It's a good practice to get into.

Also, if anyone in the Orlando area is interested in lighting, send me a PM.
Both when I was a TD and now, the fixtures are cleaned, bench focused and inspected before each show. The use of Minreal Spirits scares me both because of it's flash point being between 85 and 105F. and the possiblility it could etch the glass.

De-Natured Alcohol and a lint free cloth such as "Sur-Wipes" or camera cleaning tissues are specified by the manufacturers to clean bulbs. This will evaporate leaving zero residue. Since the alcohol is a vehicle only, the intent is for it to pick up anything on the lamp to easier lift from the surface of the glass. Should you not have a lint free cloth, do not use things like paper towel because it will leave a paper lint on the surface because it can leave paper lint/dust on it. Instead spray extra amounts of denatured alcohol on it and let the dust/dirt and hopefully oils from the skin drip off the lamp once lifted.

This can also be used for reflectors and lenses and is specified for dichroic coated lenses and reflectors especially. To a certain extent you can use glass cleaner because soap has even better lifting properties than alchol. It is than absolutely necessary to use the alcohol to remove any residue left over from the soap otherwise that soap will smoke and burn into the surface. If the reflector is aluminum, some amount of metal polish can also be used as long as it's also cleaned with the alcohol.

On lamps it is also a good idea to have some latex or latex free inspection/medical gloves around because as long as they are powder free they will not require you to clean the bulb after touching them. This is however as long as the same gloves you are touching the instrument, floor and other things dirty are not the same ones you are touching the lamp with.

Beyond this, on another forum or here discussions of the use of vineager on lenses and possibly reflectors has shown some merit as with putting the lenses in a dish washer and letting it do it's thing.

Out of the manual:
Lamp Installation on Lekos: Loosen fastening screws on socket cap of instrument and pull cap directly out. Caution if a lamp is already in the fixture, it could be difficult to remove without breaking especially if the lamp is hot or has been bloated out of shape. In the case of a bloated lamp, it is better to let the instrument cool and take it out of the fixture while the cap is still installed by opening up the rear housing. Removing a lamp from a base can be difficult and dangerous. If possible rock the lamp out of its base by touching the lamp base only. If it is stuck, grasp the lamp with gloves for extra support. If the lamp is loose in its base this is not possible. It might if none of this works it might be necessary to break the lamp off from its base and use pliers to pull the lamp or a screw driver to pry the lamp out of its base. When possible, never remove and change lamps overhead as the lamp can burst and shower glass to those below the fixture.
Insert the new lamp fully into the socket. Be sure the lamp is properly seated by holding the socket cap in both hands and pressing down on both sides of the lamp base with your thumbs. Keep the plastic or foam covering the lamp until it is ready to be re-installed into the fixture to prevent it from being touched. Caution: do not touch the glass portion of a lamp with your hands. Agents such as sodium, grease, or oil from your fingers may be transferred to the glass wall. These contaminates can cause the lamp to rupture or can greatly reduce the performance and life of the lamp. If accidently spoiled, immediately clean the lamp with a soft, clean, lint-free cloth soaked in methylated spirits (denatured alcohol), and then polish with a dry, soft, clean, lint-free cloth.
Note: do not use higher wattage lamps than the instrument was originally rated for, the new 575 watt lamps produce a lot more heat than a 500 watt lamp, and an older style non-fluted lamp base and possibly the wiring to it will not survive the higher temperature.

Leko Safety Instructions: always wear safety goggles and gloves when servicing this equipment for any reason. Disconnect unit from electrical supply before initial lamp installation, relamping, or servicing for any reason.
Risk of electrical shock; this unit must be grounded when operating.
Do not expose the unit to rain, or use in damp or wet locations. Always store indoors.
This fixture is a sorce of intense heat and is not intenede for residential use. Risk of fire or injury, avoid contact by persons or materials. If fixture is hot, allow it to cool before relamping.
Do not operate unit with damaged cord, wires or electrical parts.
Do not touch glass portion of lamp with your hands. Agents such as sodium, grease, or oil from your fingers may be transferred to the glass wall. These contaminants can cause the lamp to rupture or can greatly reduce the preformance and life of the lamp. If accidentally soiled, immediately clean the lamp with a soft, clean, lint-free cloth soaked in methylated spirits (denatured alcohol), and then polish with a dry, soft, clean, lint-free cloth. Do not allow materials to come in contact with hot lamp. Protect lamp from abrasions and scratches.
Keep front access door closed and latched when operating this fixture. These lamps reach very high temperatures (as high as 1740°F.) Under certain circumstances, internal or external influences may cause the lamp to rupture. (360Q Series Safety Instructions and Operating Procedure, Alltman Stage Lighting Co. Inc. 1996)

Lens Cleaning: to gain access to the lenses for cleaning, or other purposes, remove the lens adjusting knob and slide the lens holder out of the unit. Remove the lens retaining ring and carefully remove the front lens. If necessary, remove the lens spacer and remove the rear lens. (It might be necessary to use rubbing alcohol or soaking the lens to remove it) Reverse this process to install the lens holder back into the unit. NOTE: be sure to note the position and orientation of the lenses before removing them to assure correct reassembly and optical correctness of the fixture. Clean the lenses with mild soap and water or a commercial glass cleaning solution and a soft, clean, lint-free cloth. Insure that the cleaning process does not leave film on the lens, since the heat from the beam will bond the film onto the surface. (Vinegar or any other Coffee Pot cleaning chemicals also work well. Also, a freshly washed lens will smoke a little when used for the first time if not rinsed well enough. This smoking is also leaving a film on the lens which will attract dirt necessitating more frequent washing.
Sorry to dig up an old topic, but on the topic of lens cleaning--has anyone tried the simple vinegar method? I've heard many times that its very good for cleaning windows and such, anyone actually use it for cleaning lenses?
Our Leko department at times will do a vineager / water solution on things like S-4 PAR lenses that get bugs or other things burned into them. IT's left there for a day or two on the stuff scraping and other things won't remove.

Normally the Vineager does not do much for the hard to remove stains.

A thought might be an ultrosonic cleaner for really hard to remove stuff.

Anyway, as always follow the manufacturer's instructions on what you can and cannot use on lesese. Some might have coatings on the lens you would need to be careful not to remove in using vineager.
How frequently fixtures are cleaned also has a lot to do with the size of the venue and inventory, and the amount of manpower available. In a large scale theatre with a several hundred fixtures it would cost phenonminal amount of money to pay a crew to sit there for hours stripping down every unit, wiping everything, greasing, retouching paint and bench focusing. If it is an educational evironment where you have a, potentially, large amount of available free labor than grand, but otherwise it gets very costly.

Wow Mineral spirits to clean a lamp ? That scares the Heck out of me. Isopropyl or denatured is truly the only way to go. Mineral spirits take an extremely long time to evaporate an leave behind residual oil particles. Most manufactuers websites contain handbooks for care and feeding of Lighting instruments. I echo others when I state our fixtures get at least a once a year strip down. Source 4's are nortorious for having bad reflectors and they should be inspected at least every six months. I refer to use coffee filters as wipes for older reflectors such as the steel ones in 360Q's etc. For S4's several manufactuers producing cleaning wipes for the sole purpose of cleaning the lamps, lens and reflector. Do not forget that most modern lighting fixtures have extremely thin < and important > coatings on them for IR filtering and dissapation using anything other then the manufacturers recommended solution of Isospropyl alcohol on these parts may remove or damage that coating ( then you might as well be using a 360 Q ).
I echo the statement that cleaning is an excellent time for inspectiion of the cord, plug and socket of an instrument. Along thos lines let me relay a short story. I was on a job for a company once, I was there to do the engineering check off and power up their lighting system as well as unbox and set a basic hang for them. There was a screw up at the manufacturers and they ship me 175 fixtures with stage-pin connecters to be hung and cabled in a twist lock house. Long story short ( too late I know) I had to change out all the plugs on site. Fully 2/3's of the Fresnels had come from the factory with the screws tightened down so hard that they had literally cut all but two or three of the strands inside each conductor. Four of the fixtures had either the Ground or Hot wire hanging loose inside the connector < having been cut by excessive force on the screw.> These were brand new fixtures straight from the factory ! now imagine a fxture that has been in use for a year or two in your theatre ! You have to inspect every part as often as possible. What you spend in man-hours on maintenance you will reap 10 times over in man-hours when you are hanging/focusing with good well maintained fixtures.

Happy cleaning !
Good reason also never to use a power tool to tighten a electrical connection - at least all the way down. Perhaps for a different but similar reason it would be the case. You can use the power tool to tighten the screw but need to do the 1/4 turn past hand tight by hand in never trusting a torque setting or battery charge amount in being even able to deliver this for a final torque. (Torque setting always important also, tight to an extreme is not good due to not only crushing/cutting problems but also resistance to current flow by way of this now resistance point.) This using the tool to tighten by way of 1/4 turn being by way of blade lock mechanism in the tool or if not blade lock, hand screw driver. Adjust the torque by way of it's setting so it's not going to gorilla grip or in it's reverse concept either not tight enough or good at the start of a battery charge but a few plugs later by way of the battery draining, no longer delivering the same torque - no matter what the clicking of the tool says. Hand tightening on the screw than is necessary by way of either finishing with the cordless screw driver by hand in using it's blade lock or with a hand screw driver if not as something to both verify and ensure.

Kind of surprised that the brass screws could cut instead of sheer the screw heads, brass when at it's sheer point is often a good indication of being a wee bit tight. Break more than an occasional brass screw while dowing a screw terminal, and one should get re-educated upon what is tight.

Another case of sheer of the strands of conductor and one that might be the case here is the use of 12ga ferrules offered with the Bates style plug while using a 16ga wire. As a general rule, two conductors of equal size when put together equal three wire sizes less than their origional wire size. In other words, if one were to fold the 16ga wire in half, it would equal 13Awg. 13Awg. is much closer to 12ga than that of 16ga. Simply stripping double the length, than folding the conductor in half will more closely match that of a 12ga ferrule, yet it's simply not done in the industry. This is potentially more of a primary cause to the problem cited than that of being too tight.

Consider the set screw of a 8-23x1/4" brass screw that is screwing down onto a tinned copper ferrule of 12ga. Not only is the wire not fitting completely within the furrule in maintaining it's overall shape and equal pressure applied to all strands, thus the furrule is not really doing it's job in applying equal pressure to the entire surface area of the wire - not helping a lot in electricial conductivity, but just as with the crushed Coke can concept of it collapsing, once the screw tightens down on the ferrule, it's going to not just crush but often cut thru the surface of the ferrule. A screw cutting thru a ferrule often can cut thru the ferrule in exposing a sharp edge that can cut right thru a 16ga wire.

This all simply because a ferrule was sized wrong for the wire used in it. Had the wire been folded in half, it will have equalled 13AWG wire and more closely fit that of the 12ga ferrule. As simlar to the full and pressurized can of Coke able to be touched at it's side, once open and empty, it crushes when someone stands atop it and it's side is simply touched.

12ga Ferrules that have 16ga wire in them and a screw terminal crusing down on them are only of slightly more advantage over that of on a Bates style connector, than screwing the screw direcly down onto the individual stands of conductor. As opposed to the turning screw cutting thru the strands of wire, instead we have the sharp edge of a compromized Coke can or in this case ferrule simply cutting thru the ferrule and it's now sharp edge cutting the strands of wire.

This all in addition to given the wire was not provided pressure equal in all it's surface area - in that some strands once flattened out would be doubled and trippled up and some would be single strand and at a higher resistance to the pressure of the connection, you now have a wire that has some of it conducting well if not badly if over-tight, and other strands not performing well due to a lack of pressure and thus also high resistance. Even if with flexing, tugging and pulling, the conductors don't come loose, the down-sizing of the wire with sufficient contact applied to it will be downsized in gauge at this screw termination and be a failure point due to resistance in both directions - pressure and lack there of.

I would more believe this to be the case of the wires having at one point been properly installed but in installing them they cut the conductor than something over - tight by way of the sheer of the brass screw torque not breaking well before this when not the case.

Since folding heat wire is not all that much easy in than at the fold getting it thru the 12ga ferrule, instead using both a 16ga insulated ferrule once sleeved with a 12ga un-insulated ferrule would be a much better option. The insulated part of the 16ga ferrule holds in place the 12ga one - this given one does not also sleeve in a 14ga ferrule between them.

Once you have a 12ga ferrule sleeved atop a 16ga one, you are now encasing the conductor and providing a surface area that a #8 screw can screw down onto. Both layers of tin coated copper than also help to prevent the screw from crushing and cutting thru the conductor by way of more metal between screw and strands of wire.

In general screw terminals on plugs is a difficult problem. Too lose, and you have melt down. Overtighten and in general it also causes heat and resistance especially once coupled with the screw terminal cutting thru conductors.
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Ship you are so amazing! I've got several of your posts saved in my lecture notes files. Thanks.

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