Kinoton glass reflector flaking

[Mark Gulbrandsen]

Actually, when the Xenex 2 came out there was a problem with reflector coating flaking off. Turned out to be a contamination in the pre-wash which Optiform did the final rinse in before it went in to the plating bath. So. don't always assume it is airflow or something you or the lamp house manufacturer did wrong.

I do however recommend checking your air flow every time you install a new lamp. Some times exhaust blower impellers do clog up with dust. Or in one case I had... a gigantic black bird plugged an 8 inch exhaust duct.

[Randy Stankey]

I've gotta' agree with Mark. Plating is a finicky business. The smallest amount of contamination can cause all sorts of problems.

When I first started working at the plating shop, there was trouble with one product that looked perfect when it was plated but, by the time it got to the customer, it had black spots all over.

The part was a copper ring that had to be plated with silver. When they left the shop, they were smooth and shiny. They were packed up and sent to New Mexico. By the time they got there, they looked like a dalmatian with spots all over. You can't just plate silver over copper because the copper will migrate through and destroy the finish. You have to nickel plate, first. Yes, that was done but there was contamination in the nickel bath that left an imperfect surface which allowed the copper to migrate through to the silver.

We went around and around on the problem for almost a month until we sent the part out to be cross-sectioned and observed under electron microscope. It was, there, they found imperfections in the nickel layer.

Finally, we had to take the whole job back, strip it to bare metal and replate it.

So, yes, I can see how invisible imperfections in the surface of the reflector that cause the silver to flake off.

If it was me, I'd clean that glass with piranha solution... a mixture of sulfuric acid and hydrogen peroxide. They call it "piranha" because it eats anything!
If you put a piece of meat in a beaker full of piranha solution, it will be completely destroyed in minutes! The stuff will clean glass to within an inch of its life.

The only problem is that piranha solution is super dangerous! Not only is it corrosive if it gets on you, it can go exothermic at the drop of a hat!

We used to use a version of piranha with ammonium bifluoride at the plating shop and it did blow up on me, one time. I still have scars from the chemical burns!

[David Ferguson]

I am not convinced it was a manufacturing defect with the reflector, as it worked for me for 4 years before going bad. I don't know how many years it was in use before that.

Nothing changed in my lamphouse in the time that I've had it, that I'm aware of. I will try and measure the fans, but if I stick my hand next to them, they feel just as they always did. I also do run my lamp at only around 800W, so I wouldn't have thought heat would be the issue.

Could a bit of dirt, dust, or something else getting onto the reflector cause this? That's my current theory, but it's backed by no evidence or science - just that I can't think of another reason. How does one clean a reflector, are there chemicals to use, others to avoid, etc.? How often?

[Ryan Gallagher]

The only problem is that piranha solution is super dangerous! Not only is it corrosive if it gets on you, it can go exothermic at the drop of a hat!

I had a night shift job in a lithography lab for a lighting company a couple years in college, one of our scarier processes involved changing the transmissive characteristics of some frosted glass using a 1:1 Hydroflouric Acid bath.

The SDS (formerly MSDS) sheet on HF reads like a horror movie plot. I had an "appropriate level" of respect and fear of that particular process. Not everyone did and there was an incident on the day shift with the maintenance dept working on the fume hood and baths just shoving his un-gloved fingers into the HF bath (thankfully not the 1:1 solution we use on that glass product). *face palm*. Folks acted quick and EMS was called immediately, thankfully he walked away having only learned a valuable lesson.

[Mark Gulbrandsen]

I am not convinced it was a manufacturing defect with the reflector, as it worked for me for 4 years before going bad. I don't know how many years it was in use before that.

Nothing changed in my lamphouse in the time that I've had it, that I'm aware of. I will try and measure the fans, but if I stick my hand next to them, they feel just as they always did. I also do run my lamp at only around 800W, so I wouldn't have thought heat would be the issue.

Could a bit of dirt, dust, or something else getting onto the reflector cause this? That's my current theory, but it's backed by no evidence or science - just that I can't think of another reason. How does one clean a reflector, are there chemicals to use, others to avoid, etc.? How often?

That's quite possible if you were running a 1600 or 2kw lamp. With the Kneisleys, if you were running a 3 or 4 kw lamp, it would happen in 6 to 8 months. but if you had a 2kw or a 1.6 installed, it could take several years to show up. And to be honest, I don't remember if they made exceptions on older reflectors or not. it's been a long time...

[Randy Stankey]

Subsurface defects can remain dormant for years before they cause problems.

If you accidentally mix lead solder with lead-free (SAC) solder, parts will, with almost 100% certainty, fail in the field. It might take a few months or several years but, yes, they WILL fail.

The parts I talked about were plated and stayed in the shop for up to a week before they were sent out. It took another week for them to get to their destination. It was a big order, sent by truck freight. They, probably, sat on the customer's loading dock for a week, after. When we got the call from the customer, out people were adamant in saying that they got contaminated, either in shipping via truck or while they were on the customer's dock. It took almost a month to sort out the problem.

When it comes to silver on glass, the smallest amount of invisible contamination can cause the plating to fail. It might not be apparent when the work is done. The part might last a decade or more before it fails but, if there is contamination it WILL fail. Like I said, plating is finicky! It's all working at the molecular level where you can't see what's happening. You can only tell what's right or wrong by analysis.

The heat cycling, moisture, dirt and vibration of a movie projector is bound to accelerate degradation of the surface plating, at some time or other. It's only a matter of time.

I'm sure that if you looked into every last detail and worked hard, it would be possible to produce "perfect" plating that will last indefinitely but at what cost? Will manufacturers want to go through all that trouble just to charge the customer more? Will the customer want to pay that much? In the end, there has to be an agreement, even if only a tacit agreement, that things are "good enough." The question is, "How good is 'good enough?'"

Hydrofluoric acid is nasty fucking stuff! I've worked with it. No fun!
The big problem with it is that it is a slow acting acid. It's actually not very strong. Fairly weak as acids go. If it gets on your skin, it won't cause a burn until hours or even days later. When it does, it will cause the skin and flesh to peel right off the bone! What's more, it absorbs through the skin and gets into the bloodstream where it attacks the calcium in the bones, turning them to the consistency of Styrofoam!

If you come into contact with HF, you won't know if until your skin peels off, you get sick and, then, your bones turn to Styrofoam and crumble! Not a nice way to go!

A slightly better alternative to HF is Ammonium Bifluoride. When mixed with water the ammonium ion dissociates from the fluoride and turns into a dilute solution of HF. It plating, that's the way to go if you can use it that way. Sometimes, you don't want the ammonium floating around to mess with your reactions and you must use pure HF.

One time, at the plating shop, we used this bath which was a mixture of acetic, nitric and hydrofluoric acids to clean parts before plating. The tank was made of Delrin or Nalgene or something because you can't use a metal tank. The seams were supposed to be heat welded. Well, one of those seams broke open and spilled the solution all over the floor.

Guess who was the one who had to clean it up, wearing a moon suit, using a shop vac in 100º heat and 100% condensing humidity?

[David Ferguson]

So is it all pretty much just luck? Or are there any things I can do to try and prevent or delay this in the future? I'm talking things like more cooling, regular cleaning/inspections, rotating the reflector, stuff like that.

[Ryan Gallagher]

One time, at the plating shop, we used this bath which was a mixture of acetic, nitric and hydrofluoric acids to clean parts before plating. The tank was made of Delrin or Nalgene or something because you can't use a metal tank. The seams were supposed to be heat welded. Well, one of those seams broke open and spilled the solution all over the floor.

Guess who was the one who had to clean it up, wearing a moon suit, using a shop vac in 100º heat and 100% condensing humidity?

Yikes. Yeah I was gonna mention all the bloodstream absorption and sub-cue/calcium effects. You summed them up better than I would have. Being a small litho-lab for a non semi-conductor industry. Our station was made out of such plastics too, fume hood but not a fully enclosed variety, so when on that side of the curtain you had to wear a full respirator, gloves and apron with your bunny suit too. The station was needed cause a lot of the HF reactions are exothermic, and for process control the tanks had to be cooled to a steady temp. We lacked a 1:1 tank however in the station, when we had to etch the frosted glass we scarily had to transfer 1:1 HF from chem bottles into a temporary tub set atop the other tanks. And only process up to a certain bath temperature, then let it all cool off again until the next day, precariously pouring a tub back into chem bottles with a funnel.

Disposal was also scary. 50gal plastic drums, that pretty much everything went into. I didn't go near those without full PPE. I feel like they were cutting some corners with disposal for sure.

[Randy Stankey]

I don't know if you still have contact with people in that lab but, if you can, I'd mention ABF.

You can handle it using just standard PPE. (Face mask/respirator, gloves and an apron.) It's a white, crystalline powder, about like sugar only more "needle like" instead of granules. You can buy it in 100 lb sacks and store it on a cool, dry shelf for long periods of time. When you mix it with water it dissociates and turns into hydrogen fluoride and ammonium fluoride, both of which are good cleaners of metal and can etch glass.

I wasn't that worried about using HF or ABF. I dealt with a lot worse things in my tenure at that shop. We were building a new silver plating line and, sitting in the middle of the shop, there were four skids, full of red drums that contained pure sodium cyanide. There was almost three metric tons of the stuff! It comes in pellets that look like pool chlorine.

Guess whose job it was to put all that cyanide into the plating tanks?

PS: The usual lethal dose for cyanide in an average, 200 lb. man is somewhere in the neighborhood of 200 milligrams. Three tons of cyanide is enough to kill approximately 15 million people...the entire population of a large city!

[Tony Bandiera Jr]

I am not convinced it was a manufacturing defect with the reflector, as it worked for me for 4 years before going bad. I don't know how many years it was in use before that.

Nothing changed in my lamphouse in the time that I've had it, that I'm aware of. I will try and measure the fans, but if I stick my hand next to them, they feel just as they always did. I also do run my lamp at only around 800W, so I wouldn't have thought heat would be the issue.

Could a bit of dirt, dust, or something else getting onto the reflector cause this? That's my current theory, but it's backed by no evidence or science - just that I can't think of another reason. How does one clean a reflector, are there chemicals to use, others to avoid, etc.? How often?

I had the same problem with the No. 1 (Note to Brad or whoever codes the forum: If you type the hashtag and 1 or 2 or any other number, it auto inserts a hyperlink to the forums....annoying.) 35mm machine at HIB 100 (see the pictures warehouse) at around the same timeframe. It reared up after the building BMS shut down my lamp exhaust during a show without warning.

I think it was a combination of heat and a defect in the coating as the No. 2 machine was undamaged, and both lamps were on for the same amount of time.

Be prepared to pay a lot to get it replaced or recoated, so choose your poison. Probably best to get a new one, then keep the damaged one as an emergency spare in case a bulb explodes.