Sciencemadness Discussion Board

Ampoule from Glass Tubing

elementcollector1 - 27-3-2013 at 11:43

I recently ordered a bunch of thin glass tubes (~5mm), and I was wondering how to make these into makeshift ampoules. The way I see it, I would first close the bottom of a tube, enter the sample, then heat the space above the sample until it's molten, then twist the tube/ampoule around and pull it off to get a good seal. Clean the top portion to use again, and repeat as necessary. Does this sound good to you?

My idea would be to skip to the part where one heats the bottom portion just above the sample until a seal has been achieved, continue heating until just a small amount of glass connects the two tubes, and when it's cool, snap it off. Good idea or bad idea? I can see it going either way, but the best point of fracture at that point is obviously the thinner portion of the wall (the melted, sealed part). So I don't think the glass would really want to fracture anywhere else...

If someone has experience with this sort of thing, do tell.

Hockeydemon - 27-3-2013 at 11:48

Nerd Rage on YouTube has a video demonstration of just that.
http://youtu.be/cve_D3tWlzE

elementcollector1 - 27-3-2013 at 12:02

That deals with pipettes in particular, and I've found that method to be poor at sealing the tubes. Either some small cracks remain, or the internal air pressure inside the thing expands with the heat and ruptures the newly created seal. Besides, the tubes are 12" long, and I'm hoping to make more than 1 ampoule out of each tube.

Endimion17 - 27-3-2013 at 12:44

Never use twisting. That's just calling for trouble. If you have a polarizing filter (if you don't, buy one, online chinese ones are just couple of $), you can see the mess it introduces after cooling.

Nurdrage's method is also not recommended because it leaves a huge blob on the top, and such seals are prone to falling off.
We've already had a thread about ampoules, and I've said I was gonna make a how-to video, but fuck it...

There are some excellent old digitized books on flameworking, you might want to check them up. Bolas, Gilbert, Barbour, Robertson, Heldman, ...

I mean, you can make a bad seal, but that's just not it. Flameworking requires constant practice. It's not like riding a bike.


The "small internal cracks" are usually a stream of disconnected air bubbles. Don't worry about that.

The mess with internal pressure differential can be solved by making the ampoule into shape until a small space remains, then letting it cool off. Then use a narrow flame to quickly seal it off. You just can't do it all at once with thin walled tubes. They either collapse or bulge out.

[Edited on 27-3-2013 by Endimion17]

Dr.Bob - 27-3-2013 at 12:47

Even with pre-made quality ampules, a good torch, and a little practice, I had a tough time sealing them well, only getting about 50% to seal well. But I may have been a hack. I would try to keep them, long enough to thermally isolate the sample below. Maybe 3-4" total length. Sealing the bottom will be easier, so once you can do that well, you are ready to try the top seal.

watson.fawkes - 27-3-2013 at 15:26

http://www.ilpi.com/glassblowing/tutorial_ampule.html

When it rains, it pours.

Pyro - 28-3-2013 at 08:30

I've found that heating and ''drawing''as E17 explained in detail to me, works really well. and no visible stress, but I havn't nearly mastered it yet! E17, we'd all appreciate if you did make a video. A picture is worth a thousand words, a 5minute video is worth 7 200 000 words!

Endimion17 - 29-3-2013 at 17:07

Check this out.



Uniform glass thickness, symmetry, compactness, aesthetics. :cool:
Guys, I'll let you stew for a while. ;)
It will take time before I make an actual video, but textual description will be posted here shortly.

elementcollector1 - 29-3-2013 at 17:15

How did you perform this act of sorcery?!
...Is that a test tube?

[Edited on 30-3-2013 by elementcollector1]

Endimion17 - 29-3-2013 at 17:25

It's not anymore. :P

It's simple, actually. All you need to do is to use a frumious firetuber and gimble the chordling while keeping an eye on the tuglacious movements of the tip of the vorpel.

;)

elementcollector1 - 29-3-2013 at 17:47

Excuse me while I go attempt to wring out my brain.
Alright, seriously now: How did you accomplish what is nothing short of a perfectly made ampoule?

CaliusOptimus - 29-3-2013 at 17:57

Ampoules are pretty simple lampworking...

Condense the end of the tube shut, pull off any excess with pliers.
Hold tube vertically, and heat a narrow area until the body of the ampoule pulls a thin section (the break point).
Do this again above the break point, and allow it to become very thin. Score it with a file, and break it off. Repeat.

A tool called 'hot fingers' makes this super fast and easy, so you don't have to finesse it so much.

If Endimion17 doesn't hurry up with that video I might beat him to it! :)

Endimion17 - 29-3-2013 at 18:39

Quote: Originally posted by elementcollector1  
Excuse me while I go attempt to wring out my brain.
Alright, seriously now: How did you accomplish what is nothing short of a perfectly made ampoule?


Yeah, it is perfect, isn't it? *smug* *swag* :D
Quote: Originally posted by CaliusOptimus  
Ampoules are pretty simple lampworking...

Condense the end of the tube shut, pull off any excess with pliers.
Hold tube vertically, and heat a narrow area until the body of the ampoule pulls a thin section (the break point).
Do this again above the break point, and allow it to become very thin. Score it with a file, and break it off. Repeat.

A tool called 'hot fingers' makes this super fast and easy, so you don't have to finesse it so much.

If Endimion17 doesn't hurry up with that video I might beat him to it! :)


Something like that. The devil is in the details.
I found my blowtorch to be rather weak for some types of tubes, namely those wider than 10mm, with thicker walls. It's really almost impossible to work with them if you want to do it quickly. I need an oxyacetylene torch... or at least an oxygen bottle to hook up to my existing equipment.

I googled "hot fingers" images. Interesting, despite my SafeSearch filter being turned on.

By all means, make a video. Why not? The more videos there are, the better.

Sedit - 29-3-2013 at 19:04

Endimion are you using MAP because i found that to work ok for borosilicate. I use to do alot of art work with glass and acetylene produced to much soot which had to be baked off.

Endimion17 - 29-3-2013 at 19:33

No, it's either too expensive here, or simply hard to get. I use a standard propane-butane mixture.
If only I had oxygen. Oxygen is a problem, too. Tank registration and test are very expensive, and has to be done every few years or the filling station won't take your order. After ten or so years, you must buy a new tank. The laws are very strict.
I can't allow myself to spend more than 80$ every few years just for a few days worth of toying with the glass. :/

I've took a photo few minutes ago or the very same ampoule through a polarizer.

<img src="http://i135.photobucket.com/albums/q136/endimion17/pokusi/Ampula.png" width="450" height="370">
(Firefox: right click, "View Image" for full sized photo)

As you can see, there's that ominous white line often seen even in the professional glassware, but that's about it. No dangerous internal stress whatsoever. If I was twisting it, there'd be some weird patterns inside.
Weak lines near the edge are the refraction, and the pair of weak ones along the middle are the smeared reflection from my camera lens.
Two coloured blobs on the left are my fingers.
This kind of looks like a condom. LOL

Oh, and BTW my camera can't record video in macro mode, so making a detailed how-to video would be very difficult. :(

[Edited on 30-3-2013 by Endimion17]

elementcollector1 - 29-3-2013 at 20:15

I use straight propane when dealing with glass. Melts the glass just fine, but the flame seems to be too wide - Would that it were like a pencil torch or some such, with a more pointed flame.

Also, I checked an ampoule of iodine I made a year or two ago, and the top seems to be cracking off - even though it was good at the time I sealed it.

What angle are you working with the ampoule, with the closing area pointed up or down? Sideways? I normally go with up, that's the easiest. Down seems like a potential good idea, because any excess would drip off rather than back onto the sides of the ampoule (messing with the thickness).

Endimion17 - 30-3-2013 at 05:58

I'd like to have a more pointed flame, too, but those ceramic tip torches aren't cheap... They'd be very useful for making holes in tubes. So far I've been using a torch lighter to do it, but they overheat in no time.

I hold the tube with the neck facing down and the flame going almost perpendicular to it. I slightly tilt it downwards to avoid excessive heating of the upper part held by hands.

It would be cool to obtain one of those flat flame adapters, too. You just can't bend tubes properly without them.

unionised - 30-3-2013 at 06:29

That ampoule is symmetrical, strain free, and useless.
There's nothing in it.

CaliusOptimus - 30-3-2013 at 09:47

Quote: Originally posted by Endimion17  
No, it's either too expensive here, or simply hard to get. I use a standard propane-butane mixture.
If only I had oxygen. Oxygen is a problem, too. Tank registration and test are very expensive, and has to be done every few years or the filling station won't take your order. After ten or so years, you must buy a new tank. The laws are very strict.
I can't allow myself to spend more than 80$ every few years just for a few days worth of toying with the glass. :/


That is surprising... getting an O2 tank in the USA is a pretty simple matter. I got a small O2/C2H2 torch set from a friend who owed me money, and since I've been upgrading it as well as changing over to propane. Both tanks were expired when I got them, but it was very little cost to get them filled. I think the hydro test fee was $10 on top of the usual fill charge, and they just exchanged my tanks for full ones and I was out the door for 50 bucks. I eventually upgraded to much bigger tanks, I've now got an 80CF O2 tank and a 20lb propane tank. The O2 fill costs about $30 and I don't have to do any maintenance at all, aside from paying a hydro test fee if I bring back an expired tank.

The first torch I had worthy of boro work used disposable cylinders, I think this is it: http://www.homedepot.com/p/Bernzomatic-Multi-use-Tote-Torch-...

PS: vid on the way

elementcollector1 - 30-3-2013 at 09:54

I've seen 1' O2 tanks at hardware stores, you sure you can't find any?

CaliusOptimus - 30-3-2013 at 10:22


http://www.youtube.com/watch?v=zMneBgZvYFY&feature=youtu...

elementcollector1 - 31-3-2013 at 11:58

Oh man, I've got to try that. Problem is, my blowtorch has a button feature where the button must be held down at all times to work. Going to see if I can't get something to remedy that; free up an extra hand for more finesse.