CurtPalme.com Home Theater Forum

[CasetheCorvetteman]

Awesome, sounds great mate

[CSX]

Update:
Control groups have exhibited no change.
I did have to create new seals for the blue tube due to some leaking, but other than that, no changes.
Removed fluid was examined from the blue tube, it shows no changes.

[Nashou66]

[cmjohnson]

I have to replace the coolant in my LC assemblies. Might as well go with this stuff if I can get it.

[Nashou66]

CSX, do you have any old small PCB's that you dont need? Try to soak some of them in this stuff to see what it might
do to electronics. or maybe not soak it but spill some on it to see if it corrodes the traces and other parts.

Nashou

[CSX]

[CasetheCorvetteman]

Hows it all looking? Im still quite keen to give this gear a shot in the Cine 9

[CSX]

[CasetheCorvetteman]

Yeah cheers mate, ill do that now.

[redfox001]

How is this doing in time? All been replaced yet?

[tschaeikaei]

Yes! It kind of sucks to read this thread after replacing the glycol (with pure glycol) in all 6 Marquee tubes i have here.
About the chemical cmoposition of this stuff: am i right that this is 100% glycerine?

And Mike: the glycol you replaced with this stuff.. was it aged, yellow stuff with fungus or did you remove "good" glycol to test this?

I refilled my tubes using pure monoethyleneglycol that looked very clear to me. But i have nothing to compare it to than water.
Regards, Julian

[redfox001]

70% ethylene glycol (kind of alcohol) and 30% glycerine. That is what I use. Barco says it is the right deflection coefficient. Else you get reflections halos and bad contrast.

[tschaeikaei]

PMMA (the material i guess C- Elements are made of) has a refraction index of 1,49.
Monoethyleneglycol 1,4318 and glycerin 1,4745. So i guess that you could end up between 1,43 and 1,47 mixing glycerine and glycol.
Afaik it would be best if the refr. index of the C-element and liquid were the same. But how to achieve that? I don't know.
Any chemists here?
Bad contrast or halos can develop everywhere in the lens. Just to remind, that you've got to use clean lenses.
Regards, Julian

[redfox001]

I wonder if Ice clear is pure glycerine

http://www.orisonmarketing.com/IceclearAF.html

That would make its refraction 1,473

The glycerine I have is rather thick so I guess they mix in the alcohol too. Perhaps it should not be to thick to get some convection?

[redfox001]

Oh by the way some more info I once found. Ice Clear is non toxic because it uses prophylene glycol.

There was some discussion about 20/80 or 30/70 and i think the 30/70 has the better refractive index.

[mc86]

Julian / others,

Just some random ramblings on this stuff.

To play "Devil's Advocate" here....I'm not so sure matching the fluid's and the RI of the lens helps much in and of itself as an optical issue. I also don't know that anyone who has done even a partial study to see increasing performance (on some axis of measure) with decreasing difference in RIs. Said another way, I would presume the design engineer of the lens assemblies would have accounted for the expected refraction occurring in the c-element given the RI of the coupling fluid specified. If so, any deviation from the specified fluid's RI may have an adverse impact on the refraction.

To evaluate the impact changing the fluid's RI would have on the refraction, Snell's law should be consulted. Snell's law describes the extent of refraction occurring at the boundary/interface between materials having different RIs. In my high school physics book, the example was a hunter aiming a spear at a fish in the water. I suppose nowadays the example is sticking a fork in a piece of tofu submerged in olive oil! Anyway, the law states that the ratio of the sin(s) of the two angles is equal to the ratio of the refractive indices. Changing the ratio of the RIs say from 1.49/1.41 (1.056) to, say, 1.49/1.45 (1.027) is so small we are talking about something less than maybe degree or two of refraction change for the light that hits the lens (for most angles, certainly from a nearly orthogonal angle). Though perhaps my imagination is poor, I don't see offhand how such a small change (or propagation of this change down the sequence of subsequent lenses) would matter to edge focus or sharpness.

Of course, going from air-coupling to ANY liquid coupling is a huge jump and any subsequent increase of the fluid RI should be thought of as an extension of the same improvement. Haloing is certainly reduced by LC systems, but I don't know the underlying optics/physics...it seems likely the RI must have something to do with this. But perhaps the curvature of the c-element lens vs the curvature of the lens closest to the tubes on air-coupled lens assemblies explains this, I dunno. Can someone explain the haloing phenomena? I feel like it has more to do with scattered light being "collected" on a planar intersection of the curved lens, but am not sure how the liquid would eliminate this...

Finally, if one sought to match the RI_fluid to be equal to the RI_lens, he/she must be careful that the fluid's RI never exceeds the RI of the lens. Once RI fluid>RI C-element, total internal reflection (TIR) would start to occur. The result would "bouncing back" light to the tube face and then back again from there with scattering, etc...bad news. Of course, I think only exotic optical fluids get to such RI values as high as that of any lens. Somewhere on here there is a thread discussing exotic (silicone-based?) fluid substitutes.
EDIT: here is the URL for a thread on "Glycols" linking to that thread...

My lab has very precise refractometers if anyone anyone every wants a measurement of something they have that is of unknown value OR wants to make a given RI value. If a given binary mixture doesn't have published literature values for the system, it is unwise to predict the RI value of a given mixture using the two pure component values. This is because the RI does not typically vary linearly with either mole or volume fraction in simple ways. Even accounting for non-ideal mixing volumes doesn't generally work well, IIRC. I suppose I am the stereotype in this respect: As an engineer, my expensive handheld refractometer will give me 1.xxx +/- 0.0005 in 30sec using only a few drops of sample...good 'nuff for quick measurements. Give me time to warm up and purge my HPLC's RI detector and I can report RI to 6+ decimal points from a known reference.

Just some thoughts,
Matt

[redfox001]

With refraction there are only no reflections when the refraction index is exactly equal. When it is lower there is some refraction, when it is higher there is some refraction too. It is comparable to impedance matching in electronics. Often coating is used to match two media with different impedances like air and glass.

The difference I see between LC and AC is the shape of the liquid lens. Are the reflections perhaps directed away from the phosphor and to the sides of the houses?

[tschaeikaei]

Anything new on the test projector?
Thank you for explaining, Matt.

[draganm]

this thread was started last march, but I first bought Ice Clear years ago and have used it with no problems. For the cost, non-toxicity, and good R- index it's a no-brainer. Also, I checked the other day and traditional "TV coolant" is now extinct as an off-the-shelf product.

[tschaeikaei]

And did you also experience better brightness and sharpness with this stuff, draganm?
Regards, Julian