Closed tubework: what can and can't I do?

Floorkasp · #1 2015-08-09, 1:53pm

I am starting to have more fun with boro tubing and am wondering how much risk I run of making something that will implode on me....

On one of my first attempts some months ago, I blew a bubble, closed it and put it aside. Only to have it implode with a massive bang when it cooled down. I have been very careful since then to make sure that at least one end is always open.

I have seen examples of closed boro tubing, and would like to know what your experiences are. I guess you can not close something when it is still hot all over. I presume that a thinner wall is more risky. I have seen simple tubing with dried flowers in them. I think they were just quickly sealed when the rest of the tube was cold?

Anyway, I would love to see examples of closed tubework and know how it is done.....

And more generally: any recommendations for resources on tubework are very welcome!

St3wY · #2 2015-08-09, 3:16pm

I probably won't be much help on this, but the reason why im posting is because i've seen a video on instagram where a glass blower made a hollow piece that I believe had a small chunk of opal inside just free floating around and he closed the tubed, annealed it all that.

When it was done on the video when he shakes it around the piece inside stuck to the walls and it even dumbfounded the dude that made it. He thought it was probably some sort of static electricity or pressurization.

I'm assuming this can be done, just as an experiment I would put anything tube wise you close up in the kiln right away and anneal and cool extremely slowly. It is my guess that if you closed up the tube and put it aside for it to rapid cool outside of a kiln the pressure in the tube and the stress of the glass was to high. Putting it in the kiln right away might relieve some of the stress in the glass enough for it to handle the pressure inside the tube.

Of course if i'm wrong you might have an exploded tube inside the kiln haha. BE CAREFUL.

These are just my thoughts. Hope I helped.

P.s. I would post a link to that video but it was a random thing on instagram haha

LarryC · #3 2015-08-12, 12:58pm

I dont do it hot. Leave a small hole. insert objects. close with hxtal epoxy. Done.

tela · #4 2015-08-12, 2:43pm

I was taught to use my tungsten pick and drill a small hole in any hollow form I make when I am finished making the object to keep it from imploding.

menty666 · #5 2015-08-12, 9:05pm

I've had something sealed implode in the kiln on me once. That was more than enough, now I leave a hole.

Floorkasp · #6 2015-08-13, 9:57am

Thanks all!
Guess it is not what I was hoping for, but good to know.
Any advice on getting a nice small hole?

LarryC · #7 2015-08-13, 3:06pm

Quote:

Originally Posted by Floorkasp

Thanks all!
Guess it is not what I was hoping for, but good to know.
Any advice on getting a nice small hole?

Really depends on what your making. If you can, dont close it completely but find a way to close the vessel top to a small hole. If you have to close it, heat a small spot and blow it thin and then heat and tweeze it open. I dont bother with a tungsten pick to make holes but others here may.

istandalone24/7 · #8 2015-08-14, 4:40am

nah you can drill a perfect tiny hole with tungsten. works great.
but having the glass and the pick at the right temp to do it cleanly takes a bit of practice.