Users/Zreyas/GlassBlowing

Thermos

This is how I do thermos, but before you read any further, I'm declaring I'm a glassblowing newbie - there is almost certainly a better method than this (please put it here if you know it).

I lost about 5 thermos until I hit on this technique, then I did 3 in a row without failures (~5k quality) and have subsequently made several more, so I think it's got some aspects of rightness to it.

I've managed to take a few screenies of the way I do it, so hopefully that'll help make it clearer what's happening. Unfortunately, the process it pretty quick moving and taking screenies causes enough lag and distraction to have knocked some quality off (ie. you should do better). Oh well, hopefully it gets the idea over :) If I get more quicksilver, I'll try to improve these a bit.

minor update: I've subsequently done a bunch more thermos and have it in the 90%+ success range. I made one tweak to the technique previously described here (heating the tip of the pipe rather than one click in), so need to update the pictures sometime.

--FaceAnkh

My more or less proven method is very much alike yours, but has been tuned to the necessary key strokes :)

Starting as you do by rushing the glas pipe in the Golry Hole. Spin the pipe constantly.

Get it back out by exactly 7 times pressing the -Key. Spin the pipe constantly.

Blow 3-4 times while spinning the rod.

Check quality and unload.

Success >90%.

-- Neutron

Better quality can probably achieved by just moving the pipe in to the necessary position heat it shortly and push the pipe all the way in to let it cool before blowing. (Problem is the 60 secs timer for my described method.)

Note: You lose your quicksilver if you try and fail!

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1. Begin the thermometer, then immediately push it almost all the way into the glory hole chamber, spinning it constantly.
2. Align it so the end part of the thermo is being heated (one push out so the very end tip isn't heated), with the centre of the heat roughly where the middle of the bowl will be. It's in the right place if you push it out 6 or 7 times.

• amendment: I'm getting better results when I heat exactly at the tip, not one push out (need to redo pics)

Glassblowing/Thermo_Guide$preblow_cooling-small.jpg

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3. Keep spinning and wait until the long part of the thermo is cool (it will get heated to a dull red as you push the pipe in) - ideally until it's black-red - if you don't wait, it will expand when you blow and you'll lose a lot of quality. By this time the bowl end of the thermo should be yellow-hot. It's fine to take your time here - 10-15-20secs still leaves plenty of time.

Glassblowing/Thermo_Guide$preblow_ready-small.jpg

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4. Blow 3 times to expand the hot part of the glass to approximately the right size, and keep spinning.

Glassblowing/Thermo_Guide$postblow-small.jpg (quality reads 200)

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5. You should now have a thermo of approximately 5k quality, depending on how much it's drooped while you're spinning it. Push the thermo back out of the heat (probably all the way inside is easiest), and spin it with an eye to pausing at the right moment to let the bowl part droop into the correct (central) position. Try to keep the thermo bowl as close to central/symmetrical as you can, spinning until it cools (or if you're quick, yank it out at a high quality - though I find this to be risky if you have less than 4K quality).

Glassblowing/Thermo_Guide$cooling-small.jpg (quality reads 200, 3983, 3000 - 3983->3000 is the effect of a single droop when taking a screenie)

Final output

Final quality was 3609 - a bit too close..

Glassblowing/Thermo_Guide$final-small.jpgGlassblowing/Thermo_Guide$goal-outside-small.jpg

Comparing the result to the goal, it's clear that some improvements could be made, though reassuring that a mess will still get through ;) The heat was probably allowed to spread a little too far along the pipe (in part due to the screenie taking time) - one tick less might have given a better bulb shape. It may be possible to achieve that by blowing earlier (a touch after picture 1). I also pulled the thermo out of the glory hole (so the screenies were clearer) rather than pushing it further in, which wouldn't have re-heated it again.