How do they do this?

Lotti · November 13, 2013, 05:47:48 PM

Now don't get me wrong, it's not the technique of blowing baubles exactly that I am asking about, it is about holes!!!! It looks as though these baubles are sealed (ie no hole top or bottom, although there might be one at the top). I understood that you had to have a hole and couldn't have a sealed hollow anything (actually I seen a tut recently in an old book where the blown item doesn't seem to have a hole!). I am confused a bit, can anyone enlighten me.

http://www.malcolm-sutcliffe.co.uk/Search.asp?types=yes&type=Baubles+by+Rosie

amareargentum · November 13, 2013, 05:55:18 PM

When I did my glassblowing course we collected a gather of glass on the end of the blowing iron. We then blew the bauble, effectively a bubble on the end of the pipe. We then cut in the top with the jacks, like a pair of dividers, narrowing the neck between the bubble and the iron, until it sealed. We then detached the bauble and added a blob of glass, pulling it out and forming a loop.
Hope that helps

Lotti · November 13, 2013, 06:30:18 PM

Quote from: amareargentum on November 13, 2013, 05:55:18 PM
When I did my glassblowing course we collected a gather of glass on the end of the blowing iron. We then blew the bauble, effectively a bubble on the end of the pipe. We then cut in the top with the jacks, like a pair of dividers, narrowing the neck between the bubble and the iron, until it sealed. We then detached the bauble and added a blob of glass, pulling it out and forming a loop.
Hope that helps

Thanks, so that's blowing glass with an iron, what about when using boro tube or is the glass different? Maybe you can do it 'glass blowing' but not with tube glass?

amareargentum · November 13, 2013, 06:33:00 PM

Sorry, I have never tried it with tube. I would have assumed that the principal was the same. I am sure that someone with more knowledge than me will help you.

bob proulx · November 13, 2013, 07:01:13 PM

You can use a boro tube.
Bob

ARBeads · November 13, 2013, 08:09:56 PM

I had the same query, asked a glass blower about it. The response made me smile "hhhhm yep there must be a load of pressure building up when they're annealing, not thought about it before, I'm not going to consider it anymore. Been making them for years like that, try it with tube they'll either go bang or not"

Not yet tried it - I will when I next get a chance, though that's going to be the New Year now.

garishglobes · November 13, 2013, 08:26:29 PM

I have always been told that there should be a hole - but when we made blown birds in the summer, Janis swore that they would be absolutely fine without. And they were! I think it may have a little to do with how the glass goes from thin to thick. If I'm right, then where the glass goes thin-to-thick quickly, there is more stress. So if your wall thickness, leading into hook thickness, is fairly nicely even it will be less of a problem. When attaching the hook, this means getting the rod thoroughly hot and blowing as you attach so that a small amount of bubble "goes up" the rod.

I have to say that her Austrian assistant who was a glassblower was less convinced, at least to start with, and I still feel safer with a hole! I guess that it could also be that a sphere is a stronger shape than some and can take more stress?

garishglobes · November 13, 2013, 08:29:32 PM

Oooh, and actually, I can also tell you that Jamie put a sealed bit of bubble in the bin. The wall wasn't that thick and when we came to empty the bin, it exploded!

Hamilton Taylor · November 13, 2013, 10:31:32 PM

They don't have to have a hole (as long as the wall thickness is enough to withstand the pressure variation), but if you don't have one, and you are still applying heat (say, to close a hanging loop), then the cooling air inside will deform any part of the bubble that gets warm enough to move. with a hole (it can be tiny; I drill mine with a piece of thin tungsten rod), if you heat the surface of the bubble a bit, it will stay where it was put.
Off-hand glassblowers have a larger mass of glass, and aren't actively reheating the work once the bubble is closed off - they just drop a bit onto the surface, and tweez it into a loop.

Lotti · November 14, 2013, 09:11:59 AM

Quote from: garishglobes on November 13, 2013, 08:29:32 PM
Oooh, and actually, I can also tell you that Jamie put a sealed bit of bubble in the bin. The wall wasn't that thick and when we came to empty the bin, it exploded!

LOL! I had an exploding marble the other day (it didn't go into the kiln, was 104 and I was impatient and was too soft etc etc etc and I mucked it up and left it out and it went bang as it cooled, gave me a fright but thankfully didn't shatter everywhere!).

Thanks for your help Amareargentum, Sean, Emma and Ruth and Andy, I did wonder if it was something to do with wall thickness. I shall carry on in the meantime just trying to get a bauble shape (!!!!) and not worry about no holes, but was just interested. The book I mentioned I am going to do a post about soon as was quite interesting but nearly all of their blown work was holeless! Back to my PPPPPPPPP................