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Topic: Lamp burned a hole in the dowser?

Thomas Jonsson
Expert Film Handler

Posts: 216
From: Bromolla, Sweden
Registered: Sep 2003

posted 07-14-2004 02:42 PM

I have Victoria 5 with 4 kW lamp. I don´t know what
metal is used for the manual dowser in the lamphouse,
but the heat makes it bend. The same thing with the
change-over dowser. Sometimes it bend so much it get
stuck and I have to straighten it out.

Between the commercials/trailers and the main film I
have a short intermission (about 20 seconds) with the
dowser down. Tonight there was a big flick and the film
melted - there was an inch big hole in the dowser!

Is it really possible the lamp heat is so intense it
can actually burn a hole in the metal, even if it seems
to be somewhat thin? Or could there be some other
explanation?

There is no hot spot, the light is even on the screen, and
it doesn´t get hotter than usual in the front of the
lamphouse.

I didn´t beleive this could happen. In my opinion the
dowser should be made to resist the heat of the lamp at
least for a couple of minutes.

Thomas

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Dominic Espinosa
Phenomenal Film Handler

Posts: 1172
From: Boulder Creek, CA.
Registered: Jan 2004

posted 07-14-2004 03:22 PM

It is entirely possible. Now I assume your intermission is with the motor off? Otherwise, yowsa that things way out of kilter.

Anywho, I've seen it happen on 3k and 4k houses in simplex 35's...Those dousers are paper thin aluminum or something. The douser in a lot of lamphouses is just as thin unfortunately. I'd recommend looking for a replacement douser much thicker than the previous.
G'luck.

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Robert Throop
Master Film Handler

Posts: 412
From: Vernon, NY USA
Registered: Jun 99

posted 07-14-2004 04:01 PM

Back in the carbon arc/changeover days one of the guys I worked with was always forgetting to close the lamphouse douser. He burned holes in many Century and older Simplex (Super, Regular and E7) shutters. The crews used to hang burned shutters on the wall with chalk arrows pointing to the holes whenever he was scheduled to work a relief trick.

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Steve Kraus
Film God

Posts: 4094
From: Chicago, IL, USA
Registered: May 2000

posted 07-14-2004 04:22 PM

This picture I posted last April shows a hole burned in a Norelco AAII shutter by a 4K xenon (actual measured power of about 3700 Watts).

(Film Yak Forum, Upload Your Forum Pics, Page 50)

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Ken Layton
Phenomenal Film Handler

Posts: 1452
From: Olympia, Wash. USA
Registered: Sep 1999

posted 07-14-2004 06:16 PM

It's possible you need a heat filter in your lamphouse. Also, always be sure to close the hand dowser on the lamphouse when the projector motor is not running.

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Adam Martin
I'm not even gonna point out the irony.

Posts: 3686
From: Dallas, TX
Registered: Nov 2000

posted 07-14-2004 10:15 PM

I've seen Christie, Ballantyne and Cinemeccanica changeover dowsers all warped or burned through by lamps as weak as 2K. This can often happen when someone turns the lamp on manually and forgets about it at the end of the show.

Changeover dowsers are designed for brief use. Always use the hand dowser for when the lamp needs to be on for more than a minute or two.

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Peter Mork
Expert Film Handler

Posts: 181
From: Newton, MA, USA
Registered: Jun 2002

posted 07-14-2004 11:28 PM

I used to spell it "dowser" too. But in fact, a dowser is someone who uses a divining rod to look for water. A douser is something that extinguishes a light, which is what we do around here.

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Jack Ondracek
Film God

Posts: 2348
From: Port Orchard, WA, USA
Registered: Oct 2002

posted 07-15-2004 12:24 AM

quote: Peter Mork
A douser is something that extinguishes a light, which is what we do around here.

ooops! Mea culpa!

As for the plates themselves, I guess that's one area I'd hand to the Pro35. The DOUSER plate... and the shutter for that matter, are both pretty thick, and don't seem to be negatively affected by brief missteps like leaving a lamphouse in manual.

... of course, I wouldn't know directly...having never done anything like that myself! [Roll Eyes]

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Dan Lyons
Jedi Master Film Handler

Posts: 698
From: Seal Beach, CA
Registered: Sep 2002

posted 07-15-2004 01:09 AM

quote: Jack Ondracek
As for the plates themselves, I guess that's one area I'd hand to the Pro35. The DOUSER plate... and the shutter for that matter, are both pretty thick, and don't seem to be negatively affected by brief missteps like leaving a lamphouse in manual.

It would take one hell of lamp to mess those things up! 1/4" thick!

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Joe Redifer
You need a beating today

Posts: 12859
From: Denver, Colorado
Registered: May 99

posted 07-15-2004 01:25 AM

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Dan Lyons
Jedi Master Film Handler

Posts: 698
From: Seal Beach, CA
Registered: Sep 2002

posted 07-15-2004 01:45 AM

Damn!!!!

Is there a gun hiding in your lamphouse?!

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Adam Martin
I'm not even gonna point out the irony.

Posts: 3686
From: Dallas, TX
Registered: Nov 2000

posted 07-15-2004 01:48 AM

quote: Peter Mork
a dowser is someone who uses a divining rod to look for water. A douser is something that extinguishes a light

We've beat that to death in a thread not worth searching for. We all know what's being discussed here.

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Chris Hipp
Phenomenal Film Handler

Posts: 1462
From: Mesquite, Tx (east of Dallas)
Registered: Jul 2003

posted 07-15-2004 02:12 AM

I've had dousers look like Joe's picture on 2k houses. Strong is making a newer type that is much more resistant. By the look of it I would say it is stainless steel instead of aluminum, but im not a metal expert.

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Jeremy Fuentes
Mmmm, Dr. Pepper!

Posts: 1168
From: Corpus Christi, TX United States
Registered: Jan 2004

posted 07-15-2004 07:03 AM

quote: Dan Lyons was the last to post
As for the plates themselves, I guess that's one area I'd hand to the Pro35. The DOUSER plate... and the shutter for that matter, are both pretty thick, and don't seem to be negatively affected by brief missteps like leaving a lamphouse in manual.

This is true. I havent seen any kind of damage done on ours when the lamp was left on manual for extended periods of time.

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