8mm Forum: Glass heat on Elmos,w hat this for?

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Topic: Glass heat on Elmos,w hat this for?

Winbert Hutahaean
Film God

Posts: 5468
From: Nouméa, New Caledonia
Registered: Jun 2003

posted March 31, 2009 11:56 PM

quote:
Most Elmos have a glass heat shield between the bulb and the gate. Some recommend removal of this heat shield which will increase the light output by about 5%.

On the other thread James says this. It is a general question, what this glass heat is for? Why only Elmos (I knew ST1200 has it) has it not the other projectors?

Any harms to remove the glass from Elmos?

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Winbert

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Yanis Tzortzis
Jedi Master Film Handler

Posts: 531
From: Greece
Registered: Aug 2005

posted April 01, 2009 05:24 AM

I guess it's for protecting the film frame from getting burnt by the lamp heat during still frame show-a feature that only the ST1200's & GS1200's have I think.
Don't know about removing it-guess it won't affect the projector's function,but obviously don't use the still frame if you do....

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Yannis

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Winbert Hutahaean
Film God

Posts: 5468
From: Nouméa, New Caledonia
Registered: Jun 2003

posted April 01, 2009 06:07 AM

I don't think ST 1200 has the still frame feature.

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Winbert

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Paul Adsett
Film God

Posts: 5003
From: USA
Registered: Jun 2003

posted April 01, 2009 07:08 AM

It's for the still frame capability. In the GS1200 it automatically swings out of the way when in the normal running mode.

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Chip Gelmini
Phenomenal Film Handler

Posts: 1733
From: Brooksville, FL
Registered: Jun 2003

posted April 01, 2009 08:26 AM

The ST 1200 should have still frame.

A common problem is the shutter will stop in the closed position and block the light. For this reason, pull out the inch advance knob in front of the focused lens on the main frame. This will slide out to make contact with gearing. By hand, you can briefly adjust the shutter position to put the light through. The picture below shows this knob and shaft above the elevation knob...

The picture will look darker in still mode, as a protection shield drops down behind the shutter wheel to prevent frame burn.

If your ST1200 is working properly, you should be able to do it.

cg

[ April 02, 2009, 12:12 PM: Message edited by: Chip Gelmini ]

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James E. Stubbs
Expert Film Handler

Posts: 104
From: Portland, OR
Registered: Apr 2007

posted April 02, 2009 08:58 PM

Winbert, the glass heat shield I'm talking about is the one contained in the lamp housing. It's in a round window w/ a slit/break through the middle. It's designed like this so that heat doesn't crack the glass. (I'm sure other projectors have these as well.) It's there to protect the film in the gate from excess heat during regular projection. The swing down heat shield is for still projection only. Don't mess w/ that if you want to use still projection or you'll get shrinky dinks on the screen! It also protects the film in the gate from burning when going from forward/reverse projection as it drops down momentarily during the switch.

Steve Osborne of The Reel Image fame suggested I take out the glass to increase light output by 5%. I've not done it yet but will now. See the photo. It's a good thing I took it out to show you as the glass was filthy!
Cheers,

--------------------
James E. Stubbs
Consultant, Vagabond, Traveler.

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Graham Ritchie
Film God

Posts: 4001
From: New Zealand
Registered: Feb 2006

posted April 03, 2009 12:13 AM

I would not recommend removing the split glass shield. The reason is "lamp cooling" is blown from the bottom... up.. there is a lot of hot air that needs to directed out the top of the projector, removing the glass will instead cause much of that hot air from your lamp to instead be blown forward towards the gate area and your film [Eek!]

its not a good idea. The GS1200 has a small aperture baffle plate with "extra cooling" that blows in the area between the back of the plate and the gate, thats how the GS1200 is set up cooling wise without any need for a split glass, by removing that glass in you ST1200 you are going to have some of that hot air heading the wrong way.

Graham.

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