Opening HeNe tubes nondestructively

This applies mostly to Melles Griot tubes. I just discovered that pesky hot-glue (not RTV) dissolves and softens in Isopropyl alcohol! should make these tubes easier to open short of putting them in the oven! thoughts?

Yep, been doing that for years! Even the RTV softens enough you can push out the tube carefully using a pipe around the larger envelope diameter or cathode plate (if you use very hot IPA).

Sigurthr said:

Yep, been doing that for years! Even the RTV softens enough you can push out the tube carefully using a pipe around the larger envelope diameter or cathode plate (if you use very hot IPA).

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never knew that. I really need to get my orange out of its cylinder non-destructively. any tips?

^Already did that haha!

I have removed hot glue many times by freezing. Just put it in the freezer or spray it with some liquid
propane. (Be careful not to set yourself on fire.) Dry ice or liquid nitrogen also work. It becomes so brittle
that it just snaps off. This probably won't work well for removing laser tubes, but is great any time the glue
is exposed. Sometimes it all comes off leaving behind no residue.

ultimatekaiser said:

never knew that. I really need to get my orange out of its cylinder non-destructively. any tips?

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if i had an orange (again) i wouldn't try to extract it. too many things can go wrong. that's me tho......

If yours is a normal MG tube, use a hacksaw to saw off the ends of the tube (carefully)! Use an eyeglass screwdriver to pry out some of the rubber stuff, and use a knife blade to unscrew the set screws. I tried using the hot water trick on the endcaps but it didn't work too well, a metal hacksaw is much easier. Aim to cut in maybe 3/4 of an inch in from where the plastic endcaps meet the metal tubing, and try and shine a flashlight in through your cut so you know where you are before you cut all the way through.

I find the screwdriver idea to work pretty well, the rubber stuff is quite tough but an eyeglass screwdriver will get the stuff out. If you can see the glass (or the orange tape for one of the spots) at each spot where the rubbery stuff was, then tug (gently) on one of the mirrors on the end of the tube the tube will slide out with a bit of resistance. The rubbery stuff isn't strong enough to hold the laser in place in the tube once you've cleared out the center of each of them.

This is how I've extracted like 6 MG tubes now and my REO orange HeNe. Hope this helps :beer:

cheech226 said:

if i had an orange (again) i wouldn't try to extract it. too many things can go wrong. that's me tho......

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It needs adjustment, and I can't do it in the cylinder

Thanks for the help guys I scraped our most of the rubber stuff In centre, but it appears to have a bunch. It's still stuck. Thinking some wire might do the trick without risking the tube.

ultimatekaiser said:

This applies mostly toe Melles Griot tubes. I just discovered that pesky hot-glue (not RTV) dissolves and softens in Isopropyl alcohol! should make these tubes easier to open short of putting them in the oven! thoughts?

Click to expand...

Just use a hot air gun

Peace,
dave

The thought of finagling a 611.9 tube out of a cylinder makes me cringe ... Though it is a 4mW rated tube, very possible that it's a bit out of alignment.

Hell, when aligned, you may get more lines from it.

Indeed. Believe me i thought about it very hard. It's rated 4-10mW and is used according to the source. I backed out the screws and used a flashlight and it looks relatively new according to what little I can see, it's like new and clean, and it starts right up. So I'm positive it can do a lot more than 1 and a half mW. My Allen simply can't get in there with it in the cylinder however, so it has to come out. Plus, then I can see the full status of the tube.