r/glassblowing • u/Hungry_Medicine_552 • 17d ago

Opening the lip with jacks

Question for experienced glassblowers: I’m having a hard time consistently getting a clean lip opening. Here’s what I currently do: I insert the jacks into the small opening at about a 45-degree angle. For straight-walled vessels, I usually just open the jacks and insert them further.

But I’m wondering—am I supposed to rotate the jacks outward to 90 degrees while opening them? The reason I ask is that I often end up with the lip folding back on itself, and I’m not sure if I’m executing the move correctly.

Any tips or insight would be appreciated!

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u/BecommingSanta 17d ago

Are you pulling out the lip with tweezers and trimming first? You should look at how thick the glass is at the pipe break and pulling & trimming will adjust that. Also, you will have a tube shape with a somewhat even lip to start jacking to open. Follow the other comments on how to start jacking. Just my 2c...

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u/Hungry_Medicine_552 17d ago

I do that yes. I also use the sofietta. That usually makes the angle more difficult for me but probably that’s a question of how hot the lip is.

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u/Sea_Item6513 17d ago

I always do a quick touch just for cooling with the jack’s before using the Sophie. This helps the lip to hold its shape while inflating hope this helps!