Crock Pot cooling woes

[simvet02]

I thought I would try the crock pot and vermiculite for cooling my beads. I usually use a fiber blanket until I can batch anneal them and haven't had problems with it but was just curious. I did a search on LE and read that some folks don't even plug the crock pot in. AND since the cord wasn't long enought to plug in I tried it last night without plugging it in. I left the beads in the vermiculite for about three hours and they felt cool to the touch. However, when I brought them up to soak them I noticed that they were all cracked. Every single one of them. Luckily I had only done about eight of them but I was sure surprised to find all of them cracked. Some lenghtwise and some cracked into pieces when I was removing them from the mandrel this morning.
For now I'm going back to the fiber blanket. Does the crock pot ever really work? Does the vermiculite have to be really deep? I did fill it up but it was a smaller crock pot. Another odd thing I noticed was that the beads felt wet as did the vermiculite when I took them out of the pot.

Strange to say the least. Was I just unlucky or is the crocp pot method just not as good of an idea as the fiber blanket?

[ewdb]

crockpot works great for me. i still use mine even tho i have a kiln. i preheat it to high and then leave it on for approx 1hr after i'm done. the beads are plunked in fairly deep with at least an inch or two of vermicultie covering them. if i'm making really big beads or a lot of beads i'll keep the lid on as well.

you may need to more evenly heat your beads in the upper part the flame (flame annealing) or consider putting them into the crockpot a bit sooner. sounds like yr breakage is thermal cracks.

also consider yr vermiculite may be damp from humidity? heat it up overnight and that should (hopefully) dry it out... my beads have never felt wet coming out of the pot.

[Dale M.]

You need to have at lest 2-3 inches of vermiculite over you hot bead. Also you may be damaging bead by not getting it into vermiculite soon enough. It has to go in as soon as it looses its glow, usually when it has solidified enough to not be misshaped pushing it down into vermiculite.

And it's never been proven that you have to plug crock pot in... Yes there will be some that adamantly say you do.... But then why am I having success with vermiculite in a old coffee can....

Dale

[simvet02]

Well, since I have never had a problem with beads cracking with the thermal blakent I'm going to assume that it wasn't that I wasn't looking at them too long. I had the crock pot full of vermiculite and it was brand new so the humidity had to have been pulled in during the cooling.

I'm wondering if the coffee can is so much deeper and this crock pot is just too shallow for what I was using it for.

[Henrywashere]

I never really had success with the vermiculite, but I also have no success at making small beads. I find anything bigger than 1cm has a problem surviving in the vermiculite. I would invest in a kiln then you wont have to worry (if you can afford 1 that is).

[theglasszone]

You absolutely HAVE to have the vermiculite good and toasty to use this crock/vermiculite process in cooling your beads. I had the opposite experience as you - my beads kept cracking in the fiber blanket, so I switched to the crock method. Worked wonders!!!

Also, there is a product called "Cooling Bubbles" from Japan. I used these with extreme success, and was even making 1 1/2" hollow and solid beads that didn't crack using the Cooling Bubbles in the crock. I have since sold my bubbles since I am about to acquire a REAL bead kiln, but I know a vendor who is trying to secure them for US distribution. I can write him and ask him to pop into this thread and post if he is getting close!

DeAnne in CA

[Intarsia]

Old coffe cans are great, I have used mine for just on 2 years & the only time I get a cracked bead is when I am careless. I have just purchased a slow cooker & new vermiculite & I am going to give it a go. I must say that everything I have read about this method says you should heat it up thats the whole point of the slow cooker in the first place!

Cheers!

[gubnavnania]

When I was using vermiculite, I only soak and remove the beads from mandrels after leave them overnight. Not 3 hours. They might be feel cool to touch but inside the beads still warmer.

The only problem I had was on winter where the room temperature drops very quickly, then I have to use heated vermiculite.

And you need to put about 1-1 1/2" gap between beads or the previous bead will have thermal crack. After 4 or 5 beads in vermiculite, then you can rearrange max the first 3 beads closer.

[Carolyn M]

When my kiln was non-functioning I tried both the fibre blanket and crock pot. The crock pot was far and away the best method for me. I did plug mine in.

[Charli!]

I use verminculite, and I've never heated it. I only leave the beads in like 20 minutes and I don't often get cracked ones (but then most of my beads are ikkle). With fiber blanket I kept squishing them, seemed to have more luck not mishaping thinsg in ther vermiculite

[Diane (clarus)]

I started using the crockpot and vermiculite a couple of months ago and I think it's saved many beads that may have cracked in the fiber blanket. I do plug it in and heat it up to high, then turn it off at the end of my torching session and wait several hours before removing the beads. My crock pot is a medium size one with about 4" layer of vermiculite.

I also tried it with and without the ceramic crock; I find that removing it works best. I didn't see any comments from anyone else about this - I'd love to hear some of your experiences.

-Diane

[Dennis Brady]

Originally Posted by clarus

I started using the crockpot and vermiculite a couple of months ago and I think it's saved many beads that may have cracked in the fiber blanket. I do plug it in and heat it up to high, then turn it off at the end of my torching session and wait several hours before removing the beads. My crock pot is a medium size one with about 4" layer of vermiculite.

I also tried it with and without the ceramic crock; I find that removing it works best. I didn't see any comments from anyone else about this - I'd love to hear some of your experiences.

-Diane

If the objective is to reduce the spead at which heat is lost, fundmantal physics dictates that a heated crock pot will slow heat loss more than an unheated one. That ain't theory and it ain't opinion. It's science.

[jesscause]

I use the crock and verm. and I like it! Usually I keep them in there for at least on hour on high then either I turn off the crock and leave it there, or I will transfer to the fiber blanket to finish cooling. I haven't had cracked beads since I started using it and I think they come out a little shinier!

[fourpawsglass]

I turn my crock pot on about 30 minutes on high before I start making a bead. I have about 2-3 inches of vermiculite covering the bead. After I am done, I leave the pot on for about an hour, then I unplug and leave the beads to cool over night. I have not had one bead crack. With the fiber blanket, I was lucky to get one bead come out without a crack.

[ArtcoInc]

As DeAnne mentioned, there is a 'new' product from Japan called 'Annealing Bubbles'.

(well, I don't know how new it really is, but it's new to us here in the US, at least for this
application)

When I was TA'ing for Akihiro 'Aki' Ohkama last February, he told me that in Japan, many artists do not use a kiln; they only use this material to cool their beads. He has seen quite large beads (1-1/2" and larger) cooled in this material.

No, it won't truly "anneal" your beads ... that requires a kiln. But, this material does work
better than Vermiculite in allowing your beads to cool down slowly.

I'm packing up now to head up to Portland for the Glass Art Society conference, but when I get back, I'll post more about this material on my web site.

Malcolm

[Alison D]

I love my aneealing bubbles. They seem to keep the glass hotter. I use them in a crock pot on high. Don't throw away your vermiculite if you were drying your mandrels in it because the bubbles don't hold the mandrels up for drying. Found out the hard way and had to get my vermiculite out of the trash so I could dip my mandrels.
I can even put 2 1/2 inch ornaments in there to cool as long as I properly heat them after blowing them.

Alison

[agw]

Has anyone had any trouble with Moretti clear cracking in the crockpot? My attempts at clear encased beads always do. I haven't tried using any of the other transparents for encasing yet.

It could be that I'm not putting them in soon enough, - or too late! but I'm not seeing all the cracks in any of the other beads. I wonder if they need to go into more heat straight off?

I've seen it posted here that Vetrofrond clear is better so was thinking of trying that also.

[simvet02]

Well, I think I'm going to go back to the fiber blanket until I get a bead kiln. I never had problems, not sure why I even decieded to try the crock pot except that I was at Walmart and got crazy.
I have a fusing kiln but the elements are in the lid and lifting it to put the beads in is just too hot especially now in the heat of the summer. Maybe in the winter....LOL

thanks for all your input.

[Alison D]

Jan,
You may have got a wet batch of vermiculite or something. There is NEVER any dampness with vermiculite cooling. The wet in contact with hot glass is going to break your beads. Please try once more. Keep your crockpot on high all day and stir your vermiculite around every now and then to make sure there is no dampness in it. Then turn it on high an hour before you start to work ( need like 4 inch depth of vermiculite) and I think you will be very happy. Do a few test beads in there and you can put the rest in your blanket and see how it goes. You already have the equiptment so don't give up yet. Just don't put anything you love in there untill you know that your wet problem has been solved. And like Dennis said if something starts hotter it will help it to cool slower. There is a ton of arguement about this but I swear it really does make a difference. I tried both ways and you must turn the crock pot on. You will loose many fewer beads than the blanket.

Good luck,
Alison

[ewdb]

i would agree, do try the crockpot again. my crockpot was a cheap $10 unit from walmart and works well even for cooling really big complex beads. i never had much success with the fibre blanket either - most of my beads broke.

if it's hot and humid where you are right now then that preheating tip should do the trick to dry out yr vermiculite

[simvet02]

Ok Alison, you talked me into it. I'll give it a try again plugged in this time. I do have to correct one thing thought. I'm using Perlite, which according to all the things I have read here is just like vermiculite. I'm just worried that the humidity here in the south may cause the moisture to form during cooling and I can't do anything about that. I'm in a basement and have to have the windows open when I torch. Can you say "sticky". We run a dehumidifyer down there but when the windows are open there isn't much point in having it running.

We shall see.......willing to test again today.

[WILDFYRE]

Oh where oh where do you get these "Cooling Bubbles"???? pleez spill it someone ! tyvm

[ArtcoInc]

Originally Posted by WILDFYRE

Oh where oh where do you get these "Cooling Bubbles"???? pleez spill it someone ! tyvm

I carry them. I'll give you all the details when I return from GAS.

Malcolm

[Lorraine Chandler]

I have been batch annealing for 3 years now with a large heavy glazed crock. I do not use heat..just the crock. I have never had cracked beads...

The heat doesn't make a bit of difference and I am proof of that. It is just a matter of finding the right combination of cooling and timing of the bead that you have just removed from the flame.

HotHead made bead...right out of the flame watch for glow to leave and colors appear then slow twist down into the vermiculite which is about 7 inches deep in the crock.

Mega torch..I slowly remove the bead from the flame letting the glow leave much slower.. sitting just left of the flame, slowly rotating the bead and cooling down..takes much longer for my Mega beads to get from the flame to the crock pot.
When the colors start to appear it too goes in by gentle twisting down into the vermiculite. I wait for at least three hours before peeking and that is for the smaller beads. I just let the larger beads and focals sit over night.

I take it back..I did have two beads crack on me and that was because I was learning how to use a new LARGE press and I got the beads way too thin, they take way more glass than I thought...they cracked before they ever got to the crock...
Lorraine

[LaurieBSmith]

A crock pot heats to less than 300 degrees....it's just not a necessary lampworking tool. If your crock pot heats to anything more than 350....throw it away, because it will eventually catch fire.

You'd be "better" off to heat up your kitchen oven and stick them in there...it will get to 500 degrees. (I am not suggesting this....but it would be a warmer alternative.)

There are better alternatives....

[Dennis Brady]

Originally Posted by LaurieBSmith

A crock pot heats to less than 300 degrees....it's just not a necessary lampworking tool. If your crock pot heats to anything more than 350....throw it away, because it will eventually catch fire.

You'd be "better" off to heat up your kitchen oven and stick them in there...it will get to 500 degrees. (I am not suggesting this....but it would be a warmer alternative.)

There are better alternatives....

How hot the crock gets is irrelevant. How much it slows cooling is everything. Anything that slows cooling is good. The more it slows cooling, the better. I remember reading somewhere that glass artisans were using all kinds of ways to slow cooling of glass for quite a long time before anybody got the idea of using electric kilns. I even remember seeing some work in a museum with a sign claiming it was made 3000 years ago. I wonder what they used to prevent the glass from cracking? Pretty sure it wasn't electric kilns.

[Leanne]

I always had to have my crockpot plugged in. i have a $1700 kiln now so rarely get broken beads (almost as rarely as I get to torch these days!).
I always found warm vermiculite would stop breaking.
I did have problems sometimes though. For eg. when I first learnt to encase I was using lauscha clear. All the beads would survive the cooling in the crockpot but then the whole entire lot of them broke when I took them to be batch annealed

[LaurieBSmith]

Placing a hot bead into an environment that is 600-800 degrees cooler is a recipe for broken beads.

Slow cooling a broken bead doesn't help much....the shock doesn't occur at the end of the cooling stage...

It doesn't matter if someone uses a crock pot, but I really am bothered when someone tells a new lampworker on a budget and with space constraints to spend even $10 on a crock pot. $10 is what can be spent on a good tool.....that works.

[Dennis Brady]

Originally Posted by LaurieBSmith

Placing a hot bead into an environment that is 600-800 degrees cooler is a recipe for broken beads.

Slow cooling a broken bead doesn't help much....the shock doesn't occur at the end of the cooling stage...

It doesn't matter if someone uses a crock pot, but I really am bothered when someone tells a new lampworker on a budget and with space constraints to spend even $10 on a crock pot. $10 is what can be spent on a good tool.....that works.

Are you suggesting that if they can't afford a kiln they shouldn't be lampworking?

Are you suggesting that instead of spending $10 on a crock pot that will very likely save numerous beads, they should not bother trying to retard cooling and instead spend the $10 on some small hand tool?

My advice? A kiln does a considerably better job at reducing thermal shock and annealing cracks than a crock pot but using a crock pot is a helluva lot better then doing nothing. A new hand tool might help make beads but will do nothing to save them.

What tool would you suggest is a better $10 investment then a crock pot?

[LaurieBSmith]

Dennis.....you see any of those suggestions in my post?

You are the king of assumptions.....

I am stating that a crock pot is a waste of money, electricity and space. A fiber blanket works better and doesn't use electricity or need a cord or outlet. To tell a new lampworker that they must have a piece of equipment that doesn't help is misleading and useless. Those are not YOUR assumptions of what I am saying. It's what I am saying.

Assume away, Dennis....but for heaven's sake, stop being contentious and trying to create a situation where none exists.

I didn't say a word about someone having to buy a kiln to lampwork. That's utterly ridiculous and a crass misstatement of what I posted.....

Is it what you believe? and that why you are stating it here??? That must be it....at least, that's what you would assume if someone else said it.