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bomrat
Joined: 10 Mar 2006
Posts: 117
Location: chicago
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| Posted: Sat Sep 29, 2007 12:45 pm Post subject: glycol |
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hay, guys, where is a good place to get glycol these days?
thanks
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Sat Sep 29, 2007 2:22 pm Post subject: |
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I've got stock at $25 for 500mL.
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nuttall_chris
Joined: 08 Mar 2006
Posts: 832
Location: Ottawa, Ontario, Canada
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CRT_Ben
Joined: 28 Aug 2006
Posts: 1684
Location: Northern Virginia
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Tom.W
Joined: 09 Mar 2006
Posts: 6635
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stefuel
Joined: 07 Mar 2006
Posts: 3353
Location: Green Harbor MA USA
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| Posted: Sat Sep 29, 2007 3:51 pm Post subject: |
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Right now I'm using medical grade distilled water with a drop of anti-fungal agent.
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Chip
A Barco is only a AmPro with training wheels
Card carrying member of the AVS chain gang.
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Tom.W
Joined: 09 Mar 2006
Posts: 6635
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| Posted: Sat Sep 29, 2007 3:54 pm Post subject: |
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Living on the edge ... 
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CRT_Ben
Joined: 28 Aug 2006
Posts: 1684
Location: Northern Virginia
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| Posted: Sat Sep 29, 2007 5:00 pm Post subject: |
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Ah crap! I paid almost double for the same thing 
As for using water - if you can keep it from corroding the aluminum, water is MUCH better at moving heat than Glycol. Glycol is only used in cars because it lowers the freezing point, and keeps aluminum parts (like some radiators) from corroding.
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Barry
Joined: 01 Feb 2007
Posts: 186
Location: Los Gatos , Ca.
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| Posted: Sat Sep 29, 2007 6:00 pm Post subject: |
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As for using water - if you can keep it from corroding the aluminum, water is MUCH better at moving heat than Glycol. Glycol is only used in cars because it lowers the freezing point, and keeps aluminum parts (like some radiators) from corroding. |
I just went through all this for my 1209 C-Element replacement. I check the temperature of the heat sink mounted on the tube through an inspection hole and they show zero temperature rise so I wonder where all this heat is. I am sure it is well dissipated by the heatsink but one would almost expect to burn their finger with what you read about the care required.
BTW, I got mine form MCM, be careful releasing the pressure as the old glycol squirted all over th place.
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Sun Sep 30, 2007 7:35 pm Post subject: |
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| stefuel wrote: | | Right now I'm using medical grade distilled water with a drop of anti-fungal agent. |
When you make chance to water did you notice any difference in projection distance?
Since water has a refractive index of about 1.33 and glycol have higher index and it have been even raised using 30% of glycerol in crt cooling fluid. It has the highest refractive index (1.47) in the group of water-soluble materials.
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Barry
Joined: 01 Feb 2007
Posts: 186
Location: Los Gatos , Ca.
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| Posted: Sun Sep 30, 2007 8:10 pm Post subject: |
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Absolutely NOTHING gets by Ile......
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stefuel
Joined: 07 Mar 2006
Posts: 3353
Location: Green Harbor MA USA
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| Posted: Sun Sep 30, 2007 10:23 pm Post subject: |
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| Barry wrote: | | Absolutely NOTHING gets by Ile...... |
Ya, but what did he just say 
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Chip
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Zebu Fellenz
Joined: 21 Dec 2006
Posts: 2567
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| Posted: Sun Sep 30, 2007 10:34 pm Post subject: |
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I think he said you can use water as a zoom lens
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Barry
Joined: 01 Feb 2007
Posts: 186
Location: Los Gatos , Ca.
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| Posted: Sun Sep 30, 2007 10:36 pm Post subject: |
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Well the C-element is an part of the lens light "circuit". When you changed the composition of the material (refractive index) you changed a critical value in that part of the lens so you should expect consequences. It may be benign. It may be a change in the focal length or a mismatch which makes focus difficult. I know enough about optics to know something will change, just not sure the final result.
PS Refractive index is a measure of the ability of a material to 'bend' light.
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stefuel
Joined: 07 Mar 2006
Posts: 3353
Location: Green Harbor MA USA
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| Posted: Mon Oct 01, 2007 1:49 am Post subject: |
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I think you'll find that the refractive index is only valid when light passes through that material only. As soon as you suspend it within a vessal of another material the index is a moot point. The tube face and c-element define the lens shape and the fluid fills the space defined. the only variable is the purity (clearness) of the fluid.
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Chip
A Barco is only a AmPro with training wheels
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nuttall_chris
Joined: 08 Mar 2006
Posts: 832
Location: Ottawa, Ontario, Canada
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| Posted: Mon Oct 01, 2007 2:06 am Post subject: |
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| stefuel wrote: | | I think you'll find that the refractive index is only valid when light passes through that material only. As soon as you suspend it within a vessal of another material the index is a moot point. The tube face and c-element define the lens shape and the fluid fills the space defined. the only variable is the purity (clearness) of the fluid. |
I don't think this is correct. Light is bent at the transistion point of the two materials and having water instead of glycol will have an effect.
As water has a lower refractive index, the light will be bent less at the transistion of the tube face to the water and the water to the plastic C-element. The light will then be entering the lens at a diffent angle. I suspect using water would allow a slightly longer throw distance for the same sized screen. But as the lens and C-element have been designed for use with glycol there may be focus issues.
Chris.
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Barry
Joined: 01 Feb 2007
Posts: 186
Location: Los Gatos , Ca.
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| Posted: Mon Oct 01, 2007 2:14 am Post subject: |
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| Quote: | But as the lens and C-element have been designed for use with glycol there may be focus issues.
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If it were easy to experiment like filling one with glycol and one with water and checking the difference, it would be interesting. But handling expensive CRTs and doing the swap is downright painful. Unless I KNOW I have a big improvemtn I don't mess with stuff. The designers did their job, not without the possibility of improvement but with a lot of failed attempts I don't wanna repeat.
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David_Web
Joined: 02 May 2007
Posts: 418
Location: Sweden
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| Posted: Tue Oct 02, 2007 3:47 pm Post subject: |
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My RG708 (LC) is still standing with no glycol in the blue tube.
So you tell me it would be safe to use water?
I mean water usually expands when hot and I don't want things to go poof.
If it is considered safe I could test just for fun. The tubes have visible text wear from some comm app or something to I don't have a lot to loose. After over 50k hours the focus is not the best ether.
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Tue Oct 02, 2007 10:02 pm Post subject: |
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| David_Web wrote: | | I mean water usually expands when hot and I don't want things to go poof. |
I think that water coefficient of heat expansion is lot smaller than crt cooling fluid, so that's not problem. But cold temperatures for example during moving could cause problems later.
Corrosion and different refractive index would be my biggest concerns.
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Barry
Joined: 01 Feb 2007
Posts: 186
Location: Los Gatos , Ca.
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| Posted: Tue Oct 02, 2007 11:39 pm Post subject: |
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The other thing is that viscosity is lower with water so leakage might be a problem more.
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