Oddball questions about CRT construction
 

Humor me here please.

1. As I understand it in modern B&W CRTS the phosphor coating is applied directly to the inside of the front of the glass envelope, and then aluminum is applied to the entire inside of the envelope. Is that correct?

2. Anyone know if this aluminum coating is reflective? That is to say, if I shine a flashlight into the neck of the tube I won't see anything on the front because the aluminum will reflect pretty much all of the light?

3. Do color CRTs have an aluminum coating? If so, is it between the shadow mask and the phosphors on the screen? Or does the shadow mask eliminate the need for aluminum coating?

4. Any idea what type of solvent would remove the aluminum from inside a CRT?

5. If I wanted to just cut off the screen part of a CRT, is there any danger due to tensions in the glass or safety glass? If I took a necked CRT to a glass shop is it something he could safely slice the front off of?

Thanks, I'm just daydreaming about fun projects.

1. The aluminum covers the front half of the "bell". It doesn't extend to the gun area. It covers some of and is connected to the interior aquadag.

2. It certainly is reflective, that is the whole reason for it to be used originally, to reflect the light that would have been wasted by going into the inside of the CRT. That brightened the picture. Not needing a ion trap was something that was realized later.

3. Good question. I'm not sure.

4. No solvent. An acid is used to remove the aluminum when tubes are rebuilt.

5. Except for later tubes that have a compression band, the stress in the glass is removed when the vacuum is released.

Awesome, that's exactly what I needed. Thanks. :)

3) Color tubes have an aluminum coating, just like monochrome.