<html><head></head><body style="zoom: 0%;"><div dir="auto">Mentioning cleaning the reflector, back when I worked on industrial lasers (cutting type, not theatrical), the big expensive primary lens would get a burned on smoke coating. This was extremely hard to get off so as an experiment I used 1 micron diamond powder in alcohol. Worked quite well, just wet a fingertip with it and rub gently. Rinse with distilled water, blow dry and back to work.<br></div>
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<div class="gmail_quote" >On May 2, 2020, at 17:28, Dale Farmer via Stagecraft <<a href="mailto:stagecraft@theatrical.net" target="_blank">stagecraft@theatrical.net</a>> wrote:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<pre class="blue">Paint flaking off of the lamp cap over time is normal, and the photons <br>don't care about that paint or lack thereof. I'll speculate here, but <br>I think ETC switched to a low or no VOC paint process and the different <br>coatings react differently.<br> Paint adhesion over time is one of those simple sounding things that <br>turn out to be stupendously complicated. formulation of the paint, <br>surface preparation of the painted surface, primer, application <br>conditions, curing conditions, working life conditions. I took a dive <br>into that a few years ago, and quickly bounced. Physics and chemistry <br>and manufacturing and end users all matter.<br><br> The reflectors, they do take on a yellowish hue on the reflector <br>surface over time. This presumably changes how it reflects or passes <br>the various wavelengths. I believe this is aging of the coating, but <br>that really is just a guess on my part. It does change the light <br>coming out the front, but I never had the means to actually measure it <br>other than using the Mark I eyeball. It seems a bit darker, but won't <br>try to quantify it more than that.<br> I will say that some fixtures that were in night clubs, before they <br>banned smoking, that the yellowish tinting of the coating was stronger, <br>but a vigorous cleaning removed a lot of it.<br> I have no doubt that ETC's local dealership would be more than happy <br>to sell you as many replacement reflectors as you care to buy. Might <br>just be easier to group the older fixtures for specials and the new ones <br>for washes.<br><br>Dale<br><br>On 5/2/2020 2:03 PM, Jon Ares via Stagecraft wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;"> I was able to go into my facilities yesterday to start prepping for a <br> buncha new fixtures, and found some interesting things, and I'm curious <br> about any other "changes" that have come to the Source Four over the <br> years...<br> <br> I have some bodies that are 2015, and others that are 2006. All use <br> 575w HPLs, some long-life, none at 750w. All the 2015s all have <br> cooked-off paint on the lamp housing. The 2006s still look fine.<br> <br> The reflectors are clean on both bodies, but the 2015 reflector has a <br> definite 'cooler' color to it... the older ones have a warmer tone. But <br> they're clean - no haze.<br> <br> So have there been changes in paint? Reflector coatings?<br> <br> - Jon<br> <br> <br> On Sat, May 2, 2020 at 10:56 AM Dale Farmer via Stagecraft <br> <stagecraft@theatrical.net <mailto:stagecraft@theatrical.net>> wrote:<br> <br> The source 4 middle bodies are, afaik, unchanged from the early days.<br> Single and double yoke bolt versions were the only distinctions, I can<br> recall.<br> Reflector housings went through a couple of changes early on. Main<br> one was adding baffles to the air vents facing back to reduce light<br> leaks.<br> <br> The lens tube revs only matter when you have a broken one needing to be<br> replaced or your are changing the glass out of an existing lens tube.<br> ETC doesn't keep old revisions in stock, so you have to purchase a<br> matching pair of the newest revision, and the unbroken half of the old<br> lens tube goes into the bin of misfit parts, in hopes that it will be<br> useful for a future broken other half of the same revision lens tube.<br> <br> trying to mate different revs of the left and right lens tube castings<br> is an exercise in futility. they designed the mating lips of the two<br> castings so they only fit together properly with the same rev. You<br> can<br> force them to go together, but now the lens tube is out of round,<br> leading to glass falling out when it's bumped, and it won't fit into<br> the<br> rest of the fixture easily.<br> <br> The lamp caps are the old 575 watt or below only, 575/750s, and the<br> dimmer doubler ones. There are lots of the old 575 caps around that<br> people drilled out to allow 750 lamps to fit, but they need that extra<br> heat sink and light blocking casting to handle the heat long term. <br> When<br> you don't have that extra heat sink, the heat messes up the dichroic<br> coating on the reflector, giving it a case of dandruff. (flakes falling<br> off) At that point you have to replace the reflector, which is a bit<br> spendy.<br> <br> <br> Dale<br> <br><hr><br> For list information see <<a href="http://stagecraft.theprices.net">http://stagecraft.theprices.net</a>/><br> Stagecraft mailing list<br> Stagecraft@theatrical.net <mailto:Stagecraft@theatrical.net><br> <a href="http://theatrical.net/mailman/listinfo/stagecraft_theatrical.net">http://theatrical.net/mailman/listinfo/stagecraft_theatrical.net</a><br> <br> <br> <br> -- <br> Jon Ares<br> <a href="http://www.arescreative.com">www.arescreative.com</a> <<a href="http://www.arescreative.com">http://www.arescreative.com</a>><br> <br><hr><br> For list information see <<a href="http://stagecraft.theprices.net">http://stagecraft.theprices.net</a>/><br> Stagecraft mailing list<br> Stagecraft@theatrical.net<br> <a href="http://theatrical.net/mailman/listinfo/stagecraft_theatrical.net">http://theatrical.net/mailman/listinfo/stagecraft_theatrical.net</a><br> <br></blockquote><br><br><hr><br>For list information see <<a href="http://stagecraft.theprices.net">http://stagecraft.theprices.net</a>/><br>Stagecraft mailing list<br>Stagecraft@theatrical.net<br><a href="http://theatrical.net/mailman/listinfo/stagecraft_theatrical.net">http://theatrical.net/mailman/listinfo/stagecraft_theatrical.net</a><br></pre></blockquote></div></body></html>