making delivery tubes

[Lis]

Does anyone have a foolproof way of making delivery tubes? and how do people get bored stoppers/corks? I am trying to avoid doing this maually (with a cork borer), I wasnt sure if to invest in a small drill or try to buy them already with the holes, but as of now I havent been able to find a supplier at a reasonable price, thanks
Lisa

[Voice]

Dear Lis,

It is a time consuming activity but it can be done. When I have made them properly, I have done it by having the glass rod held in place by clamps in a bosshead/retort stand etc. Then using two bunsen burners I have slowly, slowly heated up the glass where bending is required. The two burners allow me to heat all the particular area of glass at once. Even though I was using two b/burners, it has to be done millimetre by millimetre or you get that crushed bend in the glass. Even take the b/burners away from the glass if necessary. Come back to it later to heat up that next bit.
As I said, it is time consuming.

Maree

[Robb]

Hi Lisa,

I usually make these myself, mainly due to the fact I can use various diameters of tubing that I may need. If I was to buy pre-bored cork or rubber stoppers these already have holes cut at a specific size.

If I cut them myself, I have the required hole/s in the cork/rubber stopper of required size to siut the glass of interest. Then I simply blow the glass to the required shape and size and use this where needed.

I hope this helps..good to hear from you!!

Cheers,

Robb.....

[KimFenley]

Hi

I have to admit that I find it easier to make them generally due to the fact that getting particular rubber stopper with 2 or more holes hard to find, especially id the tubing are of different sizes.

I now have a stock set made which satisfy all needs.

Kim

[SueH]

I buy my stoppers with holes already in them. They are no dearer than solid stoppers but do have one size hole only. I have also purchased a boring machine (drill) which cost about $100 from Serrata or Scientrific - cannot remember which.

In making delivery tubes I simply use poly tubing attached to a small piece of glass tubing in the stopper. I changed to this method after having the glass tubes broken every time they went into a class.

[bernie]

When making delivery tubes I usually gat our handy man who has a fixed drill with a clamp to hold the rubber bung to drill them out. I then use small straight lengths of glass tube in the stopper and attach plastic tube to it to make the collection tube We have less breakage and the tube can be easily manipulated by the students to collect any gases under water.

[franco]

If the delivery tube is only used for experiments that don't involve heating e.g. CO2 into Ca(OH)2 produced from HCl + CaCO3, flexible straws are the way to go - especially with lower school students. Best type are Deeko Entertainers as they have a larger diameter than most. For smaller dia straws, wrap a piece of sticky tape around the end to hold it firmly in the stopper hole. Students can then bend the straw to whatever angle they want.

[ird]

Gday,

Definitely need a hole boring machine, cost effective as it lasts forever, good idea to purchase an extra set of borer tubes to have at hand in case of breakage.

Short glass tube through rubber stopper and LATEX tubing (from LIVINGSTONE) for longer lasting flexibility.
This method reduces the risk of broken glass injury to all who have to handle the collection apparatus.

[rae]

HI All,

Call me dumb what is a hole boring maching(other than a drill)??

Lorrae

[laurena]

Hi All,

I make my glass tubing by using the bunsen burner, and as mentioned previously it is very time consuming, however rewarding when they work out.

I believe you can purchase already made delivery tubes, but I am unaware of the cost.

I find that I have many broken when being used in class also, but I like the idea of using straws for junior science.

As for the stoppers I have already drilled stoppers, however we do have a drill press that we can use.

Goodluck, but have a go as it can be fun.

Laurena
Waikerie High

[Lis]

Hi all,
Thanks so much for you advice, I do like the idea of the straws, I am going to put that one forward to my teachers for the juniors. I have ordered some bored stoppers, but like you said Robb, I had to order a small amout of tubing as well.
Rae, I think the cork boring maching is like a drill with a clamp thingy, I would like one, only for the few times I need to bore a hole in a stopper, it is cheaper (at the moment) to buy them already, it does look like a nifty item to have.
I have my glass tubing cut ready for the rest of the stuff to arrive,. My head teacher bought me this fabulous glass cutter, it looks like a cigar cutter, you put the glass tube in and hold it closed, then turn the tube, and snap as per normal, no more blunt files, rough edges or splintered glass, yeah. Got it from serrata $18

thanks again
cheers
Lisa