8mm Forum: Heat shield glass

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Posted by Jenny Gilchrist (Member # 4949) on July 18, 2015, 02:51 AM:

I can see that some members have removed the heat shield glass in their projectors to improve their picture, as the glass may have been dirty, discoloured or broken. I have a Sankyo Dualux 1000H that seems to have had it's heatshield glass removed before I got it. It takes a 100W 12v EFT lamp that gets quite hot. As I am playing MY OWN 1960s film, irreplaceable and quite wonderful, I am devastated everytime my film has a hiccup (usually where my father has spliced it) and it catches and burns. This shouldn't happen. I have had 3-4 burns now, not much in 4000 feet of film, but it's irreplaceable and every tiny frame counts, right?

Has anyone ever replaced their heat shield glass? particularly with a non-original spare part?...has anyone 'cut a piece of glass' to fit? of normal glass?

Has anyone any idea of what kind of glass one could get to act as a heat shield? I am not familiar with glass types or if normal regular glass will do.

Posted by Paul Browning (Member # 2715) on July 18, 2015, 03:58 AM:

Hi, as the name implies its there to reflect back towards the lamp uv and the heat,this will burn through your film frames in an instant. There is enough heat build up at the gate of a projector to cause irreversible damage to film, it is special heat reflecting glass, and not standard normal glass. This is found in some down lighter halogen lamps that you buy as a uv protector, however some projectors have a freshnel screen type, or prismatic diffuser type glass.

Posted by Barry Fritz (Member # 1865) on July 18, 2015, 09:10 AM:

I think it would be very difficult to fashion a heatshield on that machine. I would suggest trying to pick up another machine to use for your project, that has the heatshield intact and has one of the newer halogen lamps that are inexpensive and readily available. The Sankyo 2000H would be a good example.

Posted by Andrew Woodcock (Member # 3260) on July 18, 2015, 02:11 PM:

Paul's advice is spot on! The heat shield and split glass etc are very much a necessity to stop the film being destroyed and therefore should always be in place on the machines that need them, mainly the ones that use the lamp on almost full power for still frame facility.

Therefore updating a machines lamp for a more powerful one etc without considering the impact this would have on a non moving frame on a projector designed without such protection, would be a mistake.

Some of the better machines use the motor circuitry protection to cut the power in an instant to the drive motor should, for whatever reason, the film stop moving.
E.g.: a broken drive belt.
This way there is no chance of your precious films being damaged from the lamp burning through a motionless single frame.

Posted by Barry Fritz (Member # 1865) on July 18, 2015, 03:06 PM:

Paul, Andrew, neither of you have answered her question. She is well aware of the dangers of not having the heat shield on her machine.

Posted by Andrew Woodcock (Member # 3260) on July 18, 2015, 05:02 PM:

As you said Barry, short of finding an identical parts machine,there is no magic wand that can come up with a heat shield that was already removed. I was just agreeing with Paul's comments and elaborating somewhat on the importance of the glass or diffuser as some machines have and how some machines that use the very same powerful lamps, don't need either.

Even if Jenny knew all of these facts, I am certain not everyone who reads the forum posts would.

Your advice was the best for Jenny, Barry. After all, for one off home movies you would want the best film handling machine money can buy to guarantee each time these precious films are viewed, they come out the other end exactly the same.

Posted by Barry Fritz (Member # 1865) on July 18, 2015, 06:41 PM:

Jenny, if she does not chime in on this thread, try to PM Janice Glesser of this Forum. She has a Sankyo 1000 that she removed the shield from. There might be a chance she still has it and will part with it. She found that by removing it, the picture was much brighter.

Posted by Janice Glesser (Member # 2758) on July 18, 2015, 07:24 PM:

Jenny, I do not have the heat shield glass I removed. If the spices are causing the film to jam in the projector, I suggest you go thru the reels with a viewer/editor and replace the problematic splices. Have you cleaned your films?..If not, this would be a good time to clean and repair the bad splices. This will improve the film feed. If properly adjusted spliced film should run smoothly thru the Sankyo 1000.

Posted by Paul Browning (Member # 2715) on July 18, 2015, 07:27 PM:

I think the questions were answered, don't use any other glass other than the correct heat reflecting glass, this implies don't use normal glass ( whatever that is), no I have not tried to make one, because I would not use a projector without this in place, because of the results you are getting. I would replace the splices with new one's as these appear to be the course of your problem. Some down lighters have this glass at the front of the unit, so look sealed, however removing this would be difficult but not impossible with a diamond hole glass cutter.

Posted by Barry Fritz (Member # 1865) on July 18, 2015, 10:37 PM:

Good point about the splices, Janice. The film hanging up and stopping due to a bad splice is not something you want happening even if you have the heat shield glass. If you are in the process of capturing it digitally, it would become a real pain.

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