Sciencemadness Discussion Board

Glass syringe needles?

Download - 22-11-2020 at 23:00

I bought a few glass syringes a few weeks back. I have a whole box of disposables that I'll use where I can get away with it, but for strong solvents and acids the glass ones would work well.

One problem: they're not really long enough.

Does anyone know if anyone makes glass "needles" that can attach to glass syringes? The end has a small ground joint on it so I'd expect something can fit on them.

I tried google but it gave me garbage suggestions.

I guess PTFE hose might work too but in my experience PTFE hose is not very flexible and wont fit on the end very well unless I get the size just right.

Clear_horizons_glass - 23-11-2020 at 00:26

Hey there, Download.
I believe what you are looking for is an outer Luer joint.
I could order those and make you some glass syringes. I even have a wet saw to give them a nice little drip tip if you want. I'll message you.

Download - 23-11-2020 at 01:45

Quote: Originally posted by Clear_horizons_glass  
Hey there, Download.
I believe what you are looking for is an outer Luer joint.
I could order those and make you some glass syringes. I even have a wet saw to give them a nice little drip tip if you want. I'll message you.


I can't send you a second message but they're not luer lock syringes. They look like plain plastic syringes only made from ground glass.

wg48temp9 - 23-11-2020 at 09:40

Quote: Originally posted by Clear_horizons_glass  

I could order those and make you some glass syringes. I even have a wet saw to give them a nice little drip tip if you want. I'll message you.


How do you lap both halves of the syringe and get them to fit so precisely?

unionised - 23-11-2020 at 10:02

You can get long teflon needles. They are not cheap, but they have the "proper" luer fitting.

Dr.Bob - 23-11-2020 at 16:02

I'm very confused, I have never seen a glass syringe without a luer fitting, some are just friction fit Luer, rather than a lock type with a metal lock around it. Standard needles in plastic and stainless should fit on it. I can't help much with the needles, but I have scads of various glass syringes, all have luer fittings, but some are friction, some are locking ones. But if it is a taper fitting, about 1/8" diameter, it is a Luer fitting.

Download - 23-11-2020 at 17:45

Quote: Originally posted by Dr.Bob  
I'm very confused, I have never seen a glass syringe without a luer fitting, some are just friction fit Luer, rather than a lock type with a metal lock around it. Standard needles in plastic and stainless should fit on it. I can't help much with the needles, but I have scads of various glass syringes, all have luer fittings, but some are friction, some are locking ones. But if it is a taper fitting, about 1/8" diameter, it is a Luer fitting.


I was under the impression luer is the twist type.

paulll - 23-11-2020 at 19:06

"Luer-lock," refers specifically to the twist-on type.

Dr.Bob - 24-11-2020 at 07:10

Luer fitting is the tapered part, Luer Lock is the metal twist version. They both have the same tapered part in common.

macckone - 24-11-2020 at 17:40

there are teflon needles on amazon but you have to buy 500 and they are expensive for a pack.

Clear_horizons_glass - 25-11-2020 at 20:22

I messaged ya about making one, Download.
But alternatively, if you have any experience in pulling down capillary tubes with a bunsen, you could just order an inner Luer joint (like the joint on the syringe), and as many outer joints as you want. Would be pretty simple if you have access to a bunsen or a map gas torch. Wouldn't be to different than capillary tubes.

Here's a quick little run down of how to pull down your own long borosilicate glass needles for a typical luer joint glass syringe using a bunsen burner or map gas torch.
Didymium glasses and a proper ventilation hood are strongly recommended if you will be doing this a lot.

1. Take some graphite tape, ceramic tape, or a folded slightly damp paper towel and stick it in between the two joints and twist them together to get them a little stuck.
2. rotate the inner joint in one hand, and hold onto the end of the outer joint with tweezers in the other hand.
3. Move the outer joint back and forth through a hotter flame while consistently slowly but steadily rotating. Be sure to not twist the tube, and try to rotate with your hands in synchrony.
4. When the tube is red hot and doesn't 'feel' solid, bring the tube out of the flame and begin pulling while slowly rotating at a consistent, steady pace.
5. Let the pulled down joint cool down on a surface that won't burn.
6. Use a scoring knife, a sharp piece of tungsten, or the edge of a file, put a small 'score' on the tube where you want the end to be and pull it off. Wetting the score helps, and be sure to pull and bend at the same time with the score facing away from you. Safety goggles are highly recommended if you are doing this a lot. It doesn't take much pressure with such small tubing.
Here's a more comprehensive guide on scoring and splitting up glass tubing and rod.
http://www.ilpi.com/glassblowing/tutorial_cutting.html
7. You can give it a drip tip with a dremel and some kind of diamond bit wheel. Be sure to do that under running water, and with safety goggles.
8. If you would like you can touch the freshly scored end of the tube to the side of the flame to 'flame polish' it so it's less sharp. Be careful as it does not take much, and it's very easy to close up the end of the tube.
9. To dislodge the two joints, use a small piece of wood to lightly tap around the outer joint while very lightly pulling the inner joint, or while angling the two in such a way that the outer joint will slide off. You can also lightly tap the outer joint against a table while lightly pulling. Try to pull by and bigger section of the outer joint left as opposed to pulling on the section that was pulled down to a smaller diameter.

Here's a video on pulling down capillary tubes:
https://www.youtube.com/watch?v=2yKHvKCatmM

Here's a link to where you can order Luer joints from Chemglass.
inner: https://chemglass.com/ground-joints-inner-luer
outer: https://chemglass.com/ground-joints-outer-luer

ErgoloidMesylate - 13-5-2023 at 20:41

Quote: Originally posted by Download  
I bought a few glass syringes a few weeks back. I have a whole box of disposables that I'll use where I can get away with it, but for strong solvents and acids the glass ones would work well.

One problem: they're not really long enough.

Does anyone know if anyone makes glass "needles" that can attach to glass syringes? The end has a small ground joint on it so I'd expect something can fit on them.

I tried google but it gave me garbage suggestions.

I guess PTFE hose might work too but in my experience PTFE hose is not very flexible and wont fit on the end very well unless I get the size just right.


I was thinking about an improvised method of a stainless steel needle with small diameter teflon tubing clamped and then teflon tape wrapped around it.