goblet foot help please!

yamaha200 · #1 2011-10-03, 4:17pm

Help! I've lost my goblet foot mojo

Used to be able to spin them out great nearly every time, but its been about a year since my last success. (ok, I didn't do goblets for several months there and its been going badly the last month or so since restarting).

Most of them turn out the same way - the top part near the punty never gets spun out enough to really flatten out, but the lip spins out so much that it starts to flare up like the edge of a top hat.

My best guess is too much heat on the lip, not enough on the inside of the bubble. But I'm turning the bubble face on to the torch pretty much as soon as I can see the lip starting to move. And of course several times I have done this and got the punty connection too hot so the whole thing goes horribly wonky. I could probably use a larger diameter punty but I can spin faster with the smaller diameter... Or is there something wrong with my setups? Onion shape just not flat enough to start with and I'm trying to flare/flatten further up than is possible?

I've tried both the Sizelove way of spinning it out right after cleaning up the lip, and the Michelson way of using a tool to flare it out nearly straight first before spinning. Same result both ways.

I'm on a lynx with an OG-15 and a big holding tank so I think I've got enough heat to do it - for this I generally run the biggest flame I can get, with it being a bit reducing (maybe 1.5" candles) to get the most heat I can out of it. I know it was easier when I had access to a Mirage, but I've been successful on the lynx before.

thanks!
laura

patienthand · #2 2011-10-03, 7:35pm

make your bubble very flat and squat, that will give you a better shape. whatever the top of the bubble looks like when you blow it, is the top of the foot. So , short and squat is the best shape. As you begin to flare the foot shoot the heat inside the bubble. Angle that you hold the foot at makes a big difference too. I start paralell to the flame and gradually raise my hand as I flare. I use mostly centrifical force once I get the bubble open and started. hope that helps and makes sense

glasskat2010 · #3 2011-10-03, 10:24pm

Quote:

Originally Posted by yamaha200

Help! I've lost my goblet foot mojo

Used to be able to spin them out great nearly every time, but its been about a year since my last success. (ok, I didn't do goblets for several months there and its been going badly the last month or so since restarting).

Most of them turn out the same way - the top part near the punty never gets spun out enough to really flatten out, but the lip spins out so much that it starts to flare up like the edge of a top hat.

My best guess is too much heat on the lip, not enough on the inside of the bubble. But I'm turning the bubble face on to the torch pretty much as soon as I can see the lip starting to move. And of course several times I have done this and got the punty connection too hot so the whole thing goes horribly wonky. I could probably use a larger diameter punty but I can spin faster with the smaller diameter... Or is there something wrong with my setups? Onion shape just not flat enough to start with and I'm trying to flare/flatten further up than is possible?

I've tried both the Sizelove way of spinning it out right after cleaning up the lip, and the Michelson way of using a tool to flare it out nearly straight first before spinning. Same result both ways.

I'm on a lynx with an OG-15 and a big holding tank so I think I've got enough heat to do it - for this I generally run the biggest flame I can get, with it being a bit reducing (maybe 1.5" candles) to get the most heat I can out of it. I know it was easier when I had access to a Mirage, but I've been successful on the lynx before.

thanks!
laura

I'm sure glad I'm not the only one that's having problems with this. I just started making goblets for our new gallery, so I guess it's to be expected.

Glasskat2010

yamaha200 · #4 2011-12-17, 9:59pm

I think my setup is ok, I really think its something I'm doing wrong on the spinning out. Here's my bubble:

Here's the setup with the punty attached, end opened, lip cleaned up:

And here's the after. Odd that this time I got one side flattened out and one side wonky. Seems like that would come from uneven heating but I usually get the heat even.

Here's a more typical result. The bubble and setup for this one looked just like the one from above:

And one other interesting thing to note. I'm getting this effect sometimes. Don't know if its from not enough heat, or too much propane (I'm running a bit reducing to get more heat out of the lynx but I've never had devit on boro clear from that before. Maybe its cause i'm using scrap tubing rather than really nice simax?). Or some other cause?

laura

HWCGlass · #5 2011-12-17, 10:25pm

word.

imo, based on the pic of your bubble, you have no chance with that setup of repeatable success.

check this. when you remove your handle, as in pic two, re melt and blow that thing out before you open your hole. blow it out a nice squat shape. domed front. place and melt in a marble at the termination point, shaped and proportioned very much like a pendant bale.

handle up to this marble, reheat and reblow you bubble just to true it to you new handle and the marble thing. then remove blow handle, then open the foot.

focus on what happens after pic one but before pic one.

think about the reblowing procedure before you place the marble thing as shaping the majority of the foots final form; that is get it really far to shape in the step.

sure this procedure limits the foot shapes you can get but it does produce decent dome/crown/hat feet.

good luck. also, clear is a nightmare. loose the clear if you can, that will help a lot, if you can't then fume the clear with silver. this will jacket and slow the surface slightly and illustrate the heat base and material thickness pretty well.

ruffeling feet also helps hide mistakes. . . .

yamaha200 · #6 2011-12-17, 11:29pm

Thanks Harold,

Any chance you've got a picture of the setup your suggesting, just to make sure I understand correctly?

I've done lots of ruffed feet recently due to this exact problem, sure would like to make an actual nice smooth foot. I have been thinking that I might need to make a bigger attachment at the punty - I like using a thin punty for ease of spinning, but I think the attachment is getting hot too easily.

I've tried in color with the same results so I went back to clear to stop wasting the expensive stuff. I see what you're saying about the silver though so I'll give that a try to see if it helps.

I can do hat type feet, but would love to be able to do flatter ones again. See for example this one from a class I took a couple years back: http://arson-studios.blogspot.com/20...let-class.html

Or even this one, which is still flatter than I can get currently: http://arson-studios.blogspot.com/20...er-goblet.html

laura

ps. you know i'm just waiting for the day you start teaching and/or writing tutorials on your amazing work!!!

Greg Cowles · #7 2011-12-18, 1:06am

Don't know about the devit, but it looks like your setup is off center.
Good luck.

Bunyip · #8 2011-12-18, 6:22am

That doesn't really look like devit, it looks more like it could be stretch marks.

That said, my goblet-newbie self has had success focusing more heat on the rim of the foot as I spin. It looks like you're getting impatient and heating too much of the bubble too hot leading to slumping, spinning faster to compensate, (possibly stretching 'cold' glass as a result of that - leading to the 'devit'), ending up slightly off center, which leads to being even MORE off center etc. Less heat and more patience has worked for me in the past with similar problems.

As have ruffles - almost literally a lifesaver

*edit: Read everything HWC said twice and apply it if you can. The man's a human lathe.

deb tarry · #9 2011-12-18, 9:37am

I have never had success spinning out a foot and that is the reason I buy them. With that being said instead of using a thicker full length rod could you attach a short section of one to the end of your favourite size of spinning rod. Then you would thinner size in your hand to spin with and a thicker end on your foot that won't heat up so fast and get wobbly.

patienthand · #10 2011-12-18, 10:44am

first.. if you start out off center, it will only get MORE off center as you work.. ALWAYS.

next as I flare I start with the heat focussed on the rin and then gradually work the flame and glass so it is angled inside the lip/bubble, I think you may be getting too much heat inside and too deep into the bubble too soon.

I have solid glass as ahandle before I ever flare as well, trying to get a nice even clean pull off and then attachment of a solid is gonna be tough to do after the flare is done.

I make a constriction before I ever blow my bubble and make a small marble shape or maria, and THEN blwo the bubble and open and flare

cjw · #11 2011-12-20, 2:47pm

hi deb,
is it possible to let me know were i can purchase foot and bowl blanks,thanks cj

deb tarry · #12 2011-12-20, 4:43pm

I get them from Glasscraft in Oregon great people and they wrap well for the mail.
http://www.glasscraftinc.com/

nevadaglass · #13 2011-12-20, 7:18pm

Abr also sells bowl and foot blanks - 10.95 ea.

http://www.dichroicimagery.com/produ...oducts_id=1739

yamaha200 · #14 2011-12-20, 10:08pm

Looking at both those options, I can make feet in those styles fairly well. Just not in a flatter style. And at this point its become a matter of pride to be able to make flat ones again since I used to be able to! Of course I don't know that my bowls will ever be as good as the commercial options...

I tried again last night, trying to incorporate some of HWCs suggestions, but no luck yet. (and yes, I tried hard to get them centered really well too.) I agree the weird marks are likely stretch marks from the lip being too cool while the glass farther back is moving. My problem is that as soon as the lip starts to expand much at all, I cannot keep any heat it with the lynx. It seems like in the past as soon as I got the lip hot enough, I turned the whole thing face on to the torch to rapidly heat the whole thing and "pop" it out all at once - it happened fairly quickly. I may have to resort to finding someone who will let me use their big torch to see if that helps keep more heat in it so I can be less impatient. I figure it will either help or make things drastically worse - either way I'll know right away

On an unrelated note, I tried the asian white tubing for the first time tonight while making Christmas ornaments. OMG! I'm in love! It melts so nice and buttery soft and stays soft forever! And it doesn't burn or boil or turn nasty colors even with some reduction flame. Looks super Christmas-y with some elvis red frit.

Thanks for all the suggestions. I'll keep trying and come back with periodic reports...

laura

deb tarry · #15 2011-12-20, 11:41pm

I think you are right in assuming that it's lack of heat. I also work with a lynx and have tried flaring and I have had no luck so far, hence is the reason that I buy them. Have you tried flaring the white tubing it sounds like it would be softer to work with. I think they say less viscosity or is it more, anyways it stays softer for a longer period of time, it might work.

yamaha200 · #16 2011-12-21, 12:09am

I also have some 104 tubing that i haven't dared to try yet. Maybe I should.

Juln · #17 2011-12-21, 1:11am

The Lynx isn't quite wide enough to make a decent goblet foot - at least not over 2 inches in diameter or so. It has plenty of heat, but it's the width that is lacking.

It would sure handle the 104 better, and if you try - good luck! It's quite blowable, but adjusting to blowing soft glass will take some time and practice. Even with 104, the problem is still width. As for the boro, you'd have more than enough heat, but what you want for blowing is a big, bushy flame that heats a large area softly. The Lynx is somewhat the opposite.

Crank it up, turn up your pressures (if possible) and work farther back in the flame.

deb tarry · #18 2011-12-21, 8:47am

I did turn down my oxy the last few times I was making a blown ornament. The results were a bushier wider flame hence the area that was heated was wider but I don't know if it will be wide enough to spin out a foot. I think you should try it and hopefully it works if it does let me know maybe I will try spinning out a foot again.

deb tarry · #19 2011-12-21, 10:48am

I just wanted to mention also (and you might already know) is the centre oxy knob should just be on a little, and this should give you a bushier flame.

yamaha200 · #20 2011-12-21, 11:04am

I always run with the green oxy cracked just a bit. And I have indeed been trying to run with the oxy turned down just a bit, both for a bushier flame and slightly higher heat as a really oxidizing flame seems cooler than neutral or slightly reducing. I have the propane at 6psi and I can build up the O2 holding tank to about 13psi before letting loose on trying to spin.

I have NOT tried working farther back in the flame though. I always instinctively go closer and closer to the face trying to get more heat. Didn't think about the fact that what I really want is the wider part that I might get at the back. Will try that too. And the 104. A while back I actually tried coil-potting some devardi to blow that out - figured the devardi would be stiff enough to not get out of control, but still not take so much heat as the boro to get soft. But I coiled it onto a metal mandrel/blow tube which was too large diameter to use with my swivel hose setup, so I couldn't see it very well and it came out less than good...

Anybody know if there is a tip I could put on my national 3b to get a wide flame? I've only got one tip on it now, that gives a nice driving narrow flame that's good for some sculpture stuff. I'm not as familiar with that torch yet...

I miss having access to a mirage

I never know whether something doesn't work because of me or because of torch too small. I usually figure its me though

I still could swear I made the foot in that Steve Sizelove class on a lynx...

Thanks again to everyone for all the tips. Surely eventually something will click!

Juln · #21 2011-12-21, 5:27pm

Don't turn your oxy down on the Lynx... turn your propane up. Or, get some tanked oxy. You need more heat to do this properly, and the purity of tanked vs. a concentrator could be the difference between now and in the Sizelove class.

You can get pretty large tips on Nationals which would give more width. I'm not a National type person, maybe someone else here can suggest. I'm thinking like the 55 or 70 hole Shelbo tips would give a wider flame that might help.

patienthand · #22 2011-12-22, 3:51pm

I agree,, for blown work you really need a bigger and softer flame, not the sharp pinpoint, I love GTT torches for lots of things, but the flame just isnt wide enough for doing most blown work on the lynx and bobcats.. cant say fo others becauze I havent tried them

Mmjmamamary · #23 2011-12-26, 11:09pm

There is a video on YouTube by Accroduster. He puts a large blown ornament on the end of of very long rod to use as his punty for spinning. The further away your hands are the more stable the axis of rotation. And the ornament on the end adds counter weight and prevents it from slipping from a loose grip.

Hth
Mary

metalbone · #24 2011-12-27, 1:41am

This guy has an interesting technique...might be helpful in some way.
http://www.youtube.com/watch?v=u4Ay7...eature=related

BAGGEDCHEVYS · #25 2011-12-28, 1:44am

laura if you are ever in the redlands area let me know you can some by the shop and i will show you my way both by hand and on the lathe and send you some with some feet.

yamaha200 · #26 2011-12-30, 6:50pm

Thanks for the offer chris, I just might take you up on that!
Thanks to the others for the video info, I will check those out.
Laura