Looking for advice on pulling down a big knuckle

[ThreeE]

I have no experience with using vac-stack tubing but have wanted to try some for a while now. I saw some knuckles on sale and decided it might be a more affordable way to try it out. What I got was a double stacked 2/3 color 1/3 clear pull that was apparently done on 74mm tubing. So it is 74mm diameter by 17mm wall on one side and 18mm diameter by 7mm wall on the other. So my question is how to I go about pulling this down? Heat it in the kiln for an hour or so? At 1050? or even higher? Then punty up to the small side? Then what?

I am feeling like I bit off more than I can chew on this one.

[Moon Munkey]

Sounds like you have the general idea. I'd go a little hoter in the kiln. I haven't pull anything that big though. You'll have you get a large handle on the knuckle side so it can take the heat. Then taper the heat. Keep it straight. Hope you have a yoke roller or two. Lol. Good luck. Let us see some b4 and after when you get it done!

[hashmasta-kut]

i do 95% of my tube pulls without rollers, but i feel i need the exercise!

how long of a knuckle section is it, and what torch do you have?

[BORO]

Cake walk.

Tube handle on the open small end.

Kiln hot. Thick Solid punty on the knuckle end. Heat , and pull. If you created positive pressure inside as you pull (blow softly during the stretch ) you will get thinner walls, and a thicker diameter.

You don't have to pull it all in one go. You can pull till you get a smaller point of lined tubing you can flame cut or "v" off and work. I never pull any of my vac stacks in one big hot pull. I pull a little at a time. Little at a time... That way I get all my tube stock the same preferred diameter.

Work the knuckle HOT. It likes to crack when it gets cold. You only need a small section to create a wig wag style ball.

A picture may help. What torch do you use? It will take some real heat to get that big piece of glass moving.

Remember the kiln is your knuckles friend. Individual worked line balls, I bench cool them. Stacked ball sections, or pieces , they get kilned too.

[hashmasta-kut]

i'll often leave my stacks standing up in the bench during assembly, and pop them in just as i am finishing up the next ball to be added. if you flame anneal stuff a bit you dont need as much kiln time and space.

[ThreeE]

Thanks for all the info guys. I am working with a Mirage and my kiln is only a small a Paragon sc2 w/out bead door. Unfortunately with this kiln there is no good way to leave a handle hanging out the door so I pretty much try to do everything in one go.

[The Goat]

you can cut a slot in the door so a blow tube can hang out. I did it to mine and use it all the time. That kiln is great on power.

[hashmasta-kut]

Thanks for all the info guys. I am working with a Mirage and my kiln is only a small a Paragon sc2 w/out bead door. Unfortunately with this kiln there is no good way to leave a handle hanging out the door so I pretty much try to do everything in one go.

just put that in the kiln with the door shut, then use grabbers or something heat resistant to handle it while you punty up to the closed end with a solid rod, then you can add a blowtube onto the other end after, then heat up, pull it out and bench cool. if you have a thick knuckle end still remove that, dont leave any super thick glass attached to your tubing after you pulled it out.

[ThreeE]

just put that in the kiln with the door shut, then use grabbers or something heat resistant to handle it while you punty up to the closed end with a solid rod, then you can add a blowtube onto the other end after, then heat up, pull it out and bench cool. if you have a thick knuckle end still remove that, dont leave any super thick glass attached to your tubing after you pulled it out.

There is no closed end. It is open all the way through.

From what you all have suggested here is the game plan I have worked out so far:
- Set the kiln to 1,100. Let it heat for an hour or so to try and get the entire mass up to temp.
- Punty some 25mm heavy wall to the smaller end then either use some hot fingers to support the back while I make the punty a nice clean hot seal.
- Bathe entire piece in heat.
- Remove the hot fingers and punty a solid rod with a "---C" shape to the 75mm open side.
- Try to get everything pretty hot and close the larger side to I have a bubble to work with.
- Attach a punty to the end of the bubble and start pulling some tube.
- Try to pull it in to 5in sections so it can fit it in the kiln.

Sound about right? Am I missing anything?

[BORO]

That knuckle looks nice. I bet it has no cracking issues.

With all that clear on one end.... I would connect up with some 25mm? Only like a few inches of 25, connected to a regular tube of 12mm? 14mm? To hold . Then paddle the big clear side closed. Thick punty , heat and pull.

Your description with a punty on a goblet top looking "c" would work as well.

If you puff into it, the clear will stretch out way faster. vs the stiffer color . That's ok.. It will reduce/condense faster as well. So it all works out. (Don't panic )

With tube pulls , and large tube. It's good to remember you can walk the heat down the tube. If the tube is getting cold when you put on the blow handle.... Start slowly at the connection / hot area. lets say it's the handle , and let the flame walk further and further into the knuckle . A inch every 15 seconds or so. Angle the flame so it licks further up the knuckle ( slowly little at a time ) working towards where you want to be heating eventually. I often heat cold tube like that with good success. If the tube is semi hot already , even better.

[BORO]

I like my tube to be about 25mm in diameter. Then I shape individual balls/wags pulling it thinner to work it as needed.

If you pull the main tube thin , like 15mm or smaller , it's much harder to condense it back into a ball, or get crisp lines.

I would try to get the line tubing you pull from the knuckle to about 25mm.

[crsaz]

What I would suggest is have a piece of blow tube with a short section of 25mm slightly flared prepped whiles its soaking in the kiln. Kiln it hot like 1175 if you have a pair of claw grabbers that will hold it. Melt small end closed handle up with solid on The small end paddle big end enough to weld your 12mm with 25mm attached. I would pull it all at once you've got the fire power and your tubing will come out nice no need to kiln it. Focus heat right on where the color ends and slightly onto the color get it nice and hot pull slightly into a football shape. Now you can just focus on the middle get it all nice and soupy pull. I usually puff mid pull and always pull vertical