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CRT Vacuum Release Made Slightly Safer

So, after harvesting a CRT monitor for parts, I was left with the tube itself. The final step was to break it so that air could rush in, but the danger of explosion made me nervous in a small apartment. Then I had an idea - I had a bunch of large plastic tubs sitting around, so I put a large scrap of foam (from a mattress topper) inside, placed the tube screen-down inside, and used a hole saw to make an opening just slightly larger then the tip of the tube in the lid of the box. With the lid on, I put on heavy gloves, goggles, jeans and heavy long-sleeve shirt, and crouched behind a deck chair. Used an old screwdriver and a rubber mallet to shatter the end, and all was well. In the event of an implosion, the plastic wouldn't stop all the shrapnel, but it would at least contain the worst of it. I hope. Any thoughts?

6 comments

Jan 18, 2012. 12:23 AMironsmiter says:

Safer is always better, so good job on thinking ahead. But it's easier and safer than you think. The most dangerous part was when you unhooked the power supply(usually some nasty large caps in there just waiting to get you)

there's always the hole where they drew the vacuum in the first place.

That's where I go...
1/4 " drill bit, light pressure.
Instead of an explosion, or broken glass, or anything like that, you get around 15 seconds of hiss(http://www.instructables.com/id/CRT-vacuum-filling/ from the "related" sidebar has a pretty good video of the sound and duration you should expect). The reason is, the vacuum hole is sealed with a metallic plug type thingie.and the area around the plug is actually reinforced(there's a thicker "rim" of glass under that stuff) Not being made of glass itself, it doesn't hold the shattering risk you get when breaking the neck.

This also leaves the entire glass intact. making it stronger overall for proper disposal, or reuse!
Now that the implosion danger is completely gone, seal it with a few drops of hot wax, and bring to the local e-waste recycler. or, use it for your own devious purposes.

Just an fyi... the "dangerous implosion" isn't really all that dangerous. it's usually more of a "phfft than a bang. And the glass everywhere but the gun is THICK.

As an added bonus, you can then pull out the "gun" without damage, for use in your personal lightsaber build.

Jan 18, 2012. 7:49 AMVoivodeNhudri (author) says:

Indeed, the flyback is the most dangerous bit- I have a short-circuiting device for dealing with those, as well as linesman gauntlets and leather gloves. My method did produce the hiss you speak of, as the vacuum released. But the negative pressure can result in a dangerous implosion if the release happens too quickly, and that implosion can send shrapnel flying. I opt for containment just in case, and as an added bonus any bits of glass that fall away during the release are held in the tub, so there's less risk of accidental contact injury. Allowed me to havest the gun components without accidental vacuum release.

Jan 23, 2012. 3:29 PMkpataska says:

Untrue. The CRT itself stores a quite dangerous charge until you ground the anode port.

Jan 24, 2012. 12:38 AMVoivodeNhudri (author) says:

Exactly what I meant. Sorry if I was unclear. I use a length of sturdy nauseated wire with an alligator clip at one end and a metal bar at the other. The clip goes to ground, and the bar slides need the "suction cup" to ensure a discharge. All this in linesman's gauntlets and leather gloves.

Jan 18, 2012. 5:57 AM

Lectric Wizard says:

Good idea !! I've used a couple of cardboard boxes in the past but the container is much safer.It "should" be able to catch all the flying glass shards. Maybe some duck tape around the neck just in case ???

Jan 18, 2012. 7:50 AMVoivodeNhudri (author) says:

Not a bad tought, although the tape would interfere wit component harvesting afterwards, I suspect.