I am SO upset and hacked off with this meadmaking lark!

[TallulahB]

Never one for understatement me, but I do so hope someone, anyone, can offer a suggestion as to what might be going wrong with my annealing schedule! PLLLLEEEAAASSSEE!!!! (Before I ruin anymore gorgeous creations.)

Lately I've had an increase in the number of beads cracking when I take them off the mandrel (you know that little tell-tale click you feel between your fingers?) I began to wonder if my annealing schedule was a bit too quick in the ramping down bit so thought yesterday I'd try to follow someone elses suggestions. FYI my original schedule was this (I have a Paragon SC-2 with bead door):

. Full ramp up to 960 F hold for 8 hours whilst I work.
. I then leave the last bead in for about half an hour.
. 300 F/hr ramp down to 840 F hold for 10 minutes.
. 300 F/hr ramp down to 400 F before turning off.

I then leave the beads to cool before soaking (sometimes overnight) in water to loosen bead release. I then use a vise to grip the mandrel whilst removing the beads (I can't get them off without the vise!) My bead release is Super Blue Sludge (if that's relevant).

Yesterday I tried the following schedule having searched the known universe for alternatives!:

. Full ramp up to 980 F hold for 8 hours whilst I work.
. I then leave the last bead in for 1 hour at that temperature.
. 225 F/hr ramp down to 700 F hold for 15 minutes.
. 900 F/hr ramp down to 100 F before turning off.

The beads were completely cool before I left in water for a few hours. The result is this: 12 good (as far as I can tell but I'm now having my doubts) beads and 15 broken. They have all split down the mandrel so from what I gather this is a sign of shock (toxic maybe!)

Most of these are pressed lentils and even include some simple round beads (which I've NEVER had break before). Once I've pressed them I always make sure they are quickly back in the flame to even out the temperature and I don't hang about getting them into the kiln. I just wait for the main glow to go and bung 'em in. I don't see how I could re-heat them any longer than I do as I've tried it and found they start to melt and distort.

By the way, if this helps, the glass is all Moretti and the lentil beads which broke were all 18mm and ranged from bases of transparent blue with silvered ivory stringer dots, some light ivory bases with stacked dots, simple round beads with melted in dots. None of them had any frit and there is no one thing common to them all. Confused - you may be. ](*,)

Apologies if this has gone on a bit but I like to give you full information to save your time. If anyone has a suggestion I'd love to hear from you.
Thanks folks. :wave:

[TallulahB]

Sorry, title should read 'beadmaking' but had a larf at that anyway!

[TallulahB]

By the way, I forgot - all were made on 1/16th mandrels. I have wondered if there wasn't enough glass around the mandrel but any more and they splurge out at the sides (if you know what I mean!) and that wouldn't explain the round which were about 10 - 15 mm.

Any definitive annealing schedule ideas out there 'cos I can't seem to find one. :)

[Melodie]

I've cracked a few fused pieces by running them under water after I thought they were room temp. Actually lost two gorgeous bowls that way. You would have thought I'd have learned my lesson the first time! Next time let them set for several hours before placing them in water.

If you want to change something in your schedule then try 150F to 700 after the 30 minute soak and then 300F to 400 and then shut off. Do not open the lid until the kiln reaches room temp.

[Islandgirl]

I ALWAYS leave my beads overnight in the kiln, a controlled cool to 500 degrees is low enough, I leave my last bead in for at least an hour at 980.... before I start to cool of the kiln, I had problems with small lentils cracking when I use bottled Oxygen but they never crack with the concentrator.... Have you changed torches or something recently???

I also spend 10 or 15 minutes looking at my beads on the mandrels (admiring or gagging!) before I put them in the water.

I use Mike Franz's old original bead release, and much prefer it air dried to flame dried, are you trapping bubbles? Actually did you change bead release or is what you're using too soupy, I can usually get 30% of my lentils off without pliers... try double dipping your mandrels for a couple of days, it may be a bead release problem!

Lynne

www.fireballbeads.com

[yeepers]

Yesterday I tried the following schedule having searched the known universe for alternatives!:

. Full ramp up to 980 F hold for 8 hours whilst I work.
. I then leave the last bead in for 1 hour at that temperature.
. 225 F/hr ramp down to 700 F hold for 15 minutes.
. 900 F/hr ramp down to 100 F before turning off.



I'm no expert on annealing schedules so don't let it be my word that you go by but it does seem to me that you're ramping down a little quickly?

At 225F/hr that's approximately 4 degrees/min. I ramp down from 960-700F over 3 hours (approximately 1.5 degrees/min) and have not had any problems with beads cracking. For what it's worth I make only pressed beads 99% of the time. I will put my beads in water after coming straight off the mandrel - sometimes while still warm and no breakage (knock on wood!!!).

Dunno if that helps or not....hopefully it does!

-Yee

[Mr. Smiley]

You can never go too slow, but you can definitely go too fast. Slow it down to 100 gegrees an hour to 850. Soak there for 20 minutes and then go 125 an hour to 600 and shut off. Don't open until the kiln is below 100. See if this makes a difference. If it doesn't, you are letting them cool too much before putting them in. If all else fails, it's a compatability problem, but the cracks you are descibing is thermal shock, not compatability.

Annealing is not cooking and it's not a race. Here's an interesting tidbit for some of the newbies... the larger you go, the slower you need to ramp down. Josh Simpson anneals his mega planets for a month or more!!! Annealing is the ramping down SLOW part too... not just the soaking at 968 part. ;)

[pam]

Mr. Smiley is right, I believe your ramp down schedule is too fast and perhaps you might let your bead temps even out a little longer before you start ramping down. Lentils by their nature have differing thicknesses and if you allow the temperature of the thinest part of the lentil to cool faster than the thickest part then you will have cracks. My second thought is why are you using Super Blue Sludge. I love it myself, but for hollow beads. I have a great deal of trouble getting solid beads off the mandrel. Is it possible you are cracking the bead release as you wind your glass and the glass is sticking to the mandrel, then when you try to get the beads off they are cracking?
Pam

[MikeAurelius]

The strain temp for moretti is 850 degrees.

I'd suggest a ramp down from 960 to 850 over 2 hours (.916 degrees per minute).
Hold briefly at 850 (I usually hold for about 10 minutes) - this allows the kiln to "catch up" to the controller
Then ramp from 850 to 400 over 2 hours (3.75 degrees per minute)
Then shut down once the kiln hits 400.

I'd also cool down your "garage" temperature from 960 to 900. With larger beads, holding them at 960 for 8 hours or more, especially on 1/16" mandrels, may cause some shape change. Garage temperature is usually about half way between the strain temp and the annealing temp, as a rough rule of thumb.

[glasskitchen]

Here is a thought-

How close are your beads to the elements?

If you ramp down past 700, the elements coming on puts a massive blast of heat on your beads.

So, your bead is at 500, and all of a sudden its next to a heat source that is a few thousand degees (or whatever the elements heat to).

It does sound like you're ramping too fast down to strain point- but after 750 (if your kiln is brick), just turn it off.

Chris

[alexm]

If slowing down your ramp rate does not do it, consider this: how old is your kiln? Could it be that you've worn out your thermocouple? That happened to me before. All was fine and then all of a sudden lots of beads started to crack. I couldn't figure out why until I changed the thermocouple and all was fine again. The unshielded thermocouples only last about 750 hours. The shielded thermocouples last a lot longer but they wear out eventually.

[SassyCassie]

I have a brick kiln and do just that Chris...turn it off. But the entire cycle takes over 8 hours...hence why I do it overnight.

I NEVER EVER EVER open the kiln for at least 3 hours after I've turned it off. I also let it get as cool as its going to get. Lost pretty beads because I wanted to "take a peek"...now I have pretty BROKEN beads to look at. Not worth it. LOTS less cracking once I found my patience. :)

Cass

[TallulahB]

Hi folks, thanks very much for all your suggestions. I will take them on board and try some of your suggested annealing times to see if they help.

To answer the queries, not in any particular order: I haven't changed torches - have always used a Minor; only place in water after they've cooled down but who knows maybe that's it; the kiln is 3 months old so don't think it's that; the bead release is not cracking as I am very careful not to be too violent when making the beads and none have stuck to the mandrels yet (in fact if I suspect the dipping is less than perfect I use another mandrel).

I did try something called Fusion Bead Separator once and still had to use some kind of grip to get the bead to release. I have been using the SBS as my supplier only had that one at the time but if I think that's got anything to do with it I will certainly try another brand. However, that doesn't explain why these have all broken when I've not had a serious problem before with this release or my methods. :-k (Note here, I have recently tried someones suggestion of getting the mandrel really hot - glowing - before applying any glass to see if that helped and must say since then find the beads come off a lot more easily but still need a vise to avoid bent mandrels).

I suspected that maybe the ramp down was a bit swift but when my first annealing schedule was even quicker, I had less breakages than I did yesterday when I slowed it down! ](*,)

Yesterdays beads were GORGEOUS so I was quite narked to lose so many. However, you live and learn and I'll keep experimenting. Thanks for all your suggestions - all gratefully received. :love:

[Mr. Smiley]

Great point about the elements... if the beads are too close, they will unevenly heat a bead below the strain point and cause cracking. Direct inline heat can do all kinds of things, like ruin the annealing process all together. Stress is formed when one part cools quicker than another. What you are trying to do is cool the whole piece (inside and out) as close to the same rate as possible. That is why the process takes a while and it's slow going. ;)

[Moth]

I think your ramp down rate between annealing temp and strain point temp is too fast. If someone else already said that, please ignore me. Good luck...sorry for your losses. ~~Mary

[MikeAurelius]

I'm gonna frown a bit at the element idea -- the elements are already "at temperature". Most controllers, when the kiln temperature is close to the set point temperature will do a fairly quick on-off cycle, usually "on" for a couple of seconds. That is not long enough to create a "blast of heat" like you'd get from the element being turned on for a minute or more.

Remember that these are resistance heaters and it takes a few moments for the elements to increase in heat from the current temperature.

I can't imagine that they would get so hot as to cause heat shock.

[Sharon Abood]

Mary, I followed your advise regarding annealing about a month ago and I haven't had another bead crack!! Thank you so much! You were right on the mark when you said I was ramping down too quickly. Now if I could just get some stinger controll. I know--PPP.
Best regards,
Sharon