CurtPalme.com Home Theater Forum

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

In early 2006 I refurbished my 9500LC, installed new tubes in used LC housings, and used Nashou66's aftermarket bellows for the LC chambers.

Not too much later, I was having issues with original VDC stock bellows weeping, and having fungus issues.

So, not too long after they first became available, (but I don't recall the date, or even the year), I bought a set of Athan's newly made aftermarket bellows and installed them in my Marquee.

He also recommended using VHT epoxy spray paint (available at your local automotive supply store) to seal the aluminum against attack from the coolant, and thus allow a longer service life for the coolant before it needs to be replaced due to contamination.

Fast forward to now.

Today's the day when I decided it was time to address a murky coolant issue.

I've redone all three tube assemblies today and I'm just about to pour fresh glycol mix into them.

I've got photos, to be posted later.

Here are my findings: The VHT epoxy worked. Though the coolant has taken on some color, it's been ten years and only now has it reached the point where I found it to be affecting my image quality to an objectionable degree.

I've never heard of getting almost ten year coolant life in a Marquee before.

The epoxy (black is what you want, to absorb stray light and keep the contrast ratio up) has kept the insides of the LC
chamber in pristine condition, looking like the day I assembled them at some point after 2006, after a quick wipedown.

The condition of the bellows is perfect. NO apparent deterioration of any kind, and no seepage.

I THINK that the slight discoloration of the glycol was due to leaching of black pigment out of the bellows, but it was
very minor and took many years to reach a state that caused me to do something about it.

I'm reusing the bellows and putting in fresh coolant and forgetting about it. I do not have any reason to think that I need to
replace these bellows at this time.

I give Nashou66's bellows a 9 out of 10, only because they MIGHT have lost some pigment into the glycol over a ten year
period of time.

His idea for using VHT epoxy to seal the aluminum parts of the chamber is a solid 10.

Using these products should be mandatory for any Marquee user.

Great job, Athan!

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Update: I found that resealing the blue tube was very problematic.

I found out just how little compression the bellows seal is actually under. I use a round nosed blunt instrument (the tip of a ball end hex driver) to probe around after setting the C element in place and torquing down the ring clamp.

I found that the blue one just had virtually NO compression on it, and that needed to be addressed, as I confirmed, by attempting to fill the chamber just to have it leak in the catch pan I do the fill work in.

So I took a length of stainless steel wire, about .013" in diameter, and placed a loop of it between the C element and the ring clamp, and tightened it down.

This seems to have done the trick. The clamp ring is now functionally a little bit thicker and pushes the C element just a little harder into the bellows sealing rings.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Success. All three assemblies are together and leak free, most of the hardware has been changed to stainless, and I begin reassembling the projector this evening. But this is only a temporary thing, as the high resolution tube equipped beast is eventually slated to become the prime movie machine in my theater.

It has occurred to me that I could use TWO projectors, and maybe do a blend on a roughly 12 foot wide screen, but I don't actually think that's a direction I want to go in.

**kal** · Posted: Tue Apr 05, 2016 12:09 pm Post subject:

FYI: These Marquee bellows are now at an all time low - 50% off! $100 for a set of 3. Includes US shipping. International is $10 more. Quantities are limited.

To order see: www.curtpalme.com/MarqueeBellows.shtm

Kal

mc86 · Posted: Wed Apr 06, 2016 11:51 pm Post subject:

I'm wondering if the black isn't pigment from the paint as much as it might be minute bits of carbon black that have come free from the surface of the rubber. Either way, pretty awesome to go a decade with so little trouble.

I'm thinking both the paint and the rubber are probably both compounded with carbon black. Carbon black is typically no bigger than 1/2um [um = micron = micrometer, not micro-inch) and often is much smaller. If the discoloration is a result of actual particles as opposed to a soluble contaminants, you might have a bit of light scattering and perhaps even some attendant polarization. Wonder if the sizes are right for this and, if so, if the magnitude would be enough to be observed with a polarized filter? It has been 20 years since I learned a little about light scattering, so maybe I'm crazy on this! Wink

Are you using the glycol I sent (eventually to the correct address!) a year or so ago, BTW? I recently tried to have one of the chemical vendors ship to a different address and they wouldn't do it anymore. Note sure if all others are following-suit...

Matt

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Yes, I used the glycol you sent me, along with about 30 percent glycerin to match VDC's formulation.

When I cleaned out the chambers, I got a bit of a black smudge off the inside of the bellows, but no smudging from the VHT paint.

So, I think the paint is completely inert as far as this application is concerned, and the rate of carbon leaching from the bellows appears to be more than acceptable by ANY metric. Ten year coolant life? In a Marquee? That has to be some kind of a record.

I took coolant samples from all three LC assemblies and saw no difference in color. I did see the shading in the blue channel on the screen, but while it was present in red and green as well, it wasn't really noticed as shading on them. It was noticed as a slight overall haze and reduction in contrast, though.

Being the cheapskate that I am, I'm considering ways to try to filter the used glycol to strip all the carbon out of it, and
restore it to like new clarity. Submicron filtration might be worth trying, but given the viscosity of the coolant, I'd expect a
very long filtration time. Maybe measured in days.