Annealing beads

[Sandra]

I have a muffle kiln with a controller and a digital pyrometer. Its not a fancy bead kiln so no programming and ramps? etc. I need to know how to batch anneal from cold, the times and temperatures (Cor F) for annealing Effetre glass. Is Moretti the same?

Sandra

[Redhotsal]

Hi,
I use a ramp from room temp to 520C at a rate of 100 degrees an hour. Once you've reached 520C you need to "soak" for at least 30 minutes though I use an hour. This is the anneal temp for Effetre. Actually the stated anneal temp for Effetre is 502 deg C but in reality in my kiln this wasn't quite hot enough.
Effetre is the same as Moretti. Moretti is the preferred nomenclature that US people use but it's the same glass. I find that this anneal curve also works for Vetrofond.
After you have soaked at the annealling temp you need to be really careful. You need to get down to the strain point which is 449 C for Effetre. this has to be done slowly or you will "lock" the stress into the glass. I use a ramp of 50 deg/hour until I get down well clear of the strain point - around 420 C. After that - you can basically turn the kiln off. But don't let the beads cool down too quickly at this point or you will get cracking due to thermal issues as opposed to stress.
This works for beads up to about 25mm diameter. If you want to go bigger than this you really have to increase that soak time almost exponentially. Bear in mind that the glass companies like to anneal large objects like paperweights for days rather than hours! though if your beads are pretty average size (15mm) this should work well.
You can get polarising filters to test your annealling cycles. I have pairs and have previously sold them. If you're interested I'll root them out and go over the procedure - if enough people are interested I'll post it up on FH.
Also - remember that kilns are like people's household ovens. One rule may not fit all - you need to experiment a little to get your anneal cycle right.
Hope this helps - not sure what you do about the ramping aside from manually turning the knob. I think that the cones you can get for ceramics will give you a pretty good indicator of the actual temp inside the kiln. My whole annealing process takes over 7 hours so you'll hve to be pretty on the ball to keep up with the cycle but I believe you can fit most basic kilns with a digital programmer as and when you get the funds.
Anyway - hope this helps a little
Sal

[Trudi]

Hi Sal

I had help with my programming - but can i ask where the information comes from - about the temp - the soaking times & cooling - is there a website?

Thanks

Trudi

[Les]

Just out of interest, can I ask if the kiln is brick lined or fiber ?? I have never seen a muffle kiln, so don't know..

I have a brick lined ceramic kiln with no fancy controller... it took a bit of playing with but I have the settings all right now and it works like a dream.. all I needed to do was find a power input level that took it up to temp over a couple of hours whilst batch annealing from cold... and as it's brick, it just switches off after the allotted soak time and cools nice and gradually.

Les xx

[Redhotsal]

Well, the answer to where does all the information come from is this:

Disclaimer: Okay, I'm going to get a little soapboxy. This really isn't a criticism of your question or yourself Trudi but this is a general comment regarding the many "newbie" style questions which are asked on FH.

When I started making beads, lampworking really wasn't very popular here, apart from GBUK there wasn't a lot of available information. So I scoured the web. There's very little information you can't find out there with Google and a few lampwork related words. There are fantastic forums - such as Wetcanvas and Lampworketc. I guarantee every Newbie related question can be found on either of those two forums. If you're using a specific glass and you can't find the annealing inforamtion on the web then the obvious thing to do is to talk to the manufacturer.

But you have to put in the time and do the research. That means wading through some very long threads, when it comes to the forums. It takes a long time. But I've done it and I'm not the biggest brain in the universe so it should be relatively straightforward for everyone else to find all the answers.

I like to help people out on this forum - we all started out at some point and there have been some very generous people who have given their time to help me and I'm grateful for that. But, learning this skill of lampworking should be a voyage of discovery. People should not expect to be spoonfed all the information that they want to receive just because they can't be bothered to find out this information for themselves.

Before anyone thinks I'm having a dig at them personally - I'm not - but I do see a lot of questions on this forum which are asked in a very lazy style. A lot of these questions can be answered by the person asking the question if they were prepared to put in a little effort.

The exception to this is when a question is asked where the answer might be beneficial to a lot of people. I don't mind answering that sort of question as it helps many. Health and safety questions too - I'd rather help someone with a gas related problem than sit wondering if they had not found the relevant information and guessed at the answer.

Hope noone takes offence to this but I hope that people do consider the time that other people have put in before they just post threads wanting information.

[Shannon]

I'm with ya on that one Sal.

No one should be lampworking/beadmaking without at least purchasing one basic instruction book (they are cheap and readily available through Amazon) which will answer most newbie questions.  It gets my goat even more when I see people who have said they own these books yet still ask these questions.

[beadysam]

When I go searching for something on the forums, I have to write down my search term cos I end up meandering all over the place on such a voyage of discovery, that I forget what I went there for!

[Sandra]

Thank you Sal for the information. The problem I found was that a lot of the instructions refer to Paragon or chilli pepper etc. ie specialist kilns and not muffle kilns.  I have searched for the information but one site for example says 940F and another site says 980 also the same 2 sites say to go down to 600 and 750 respectively.  I also have some books which differ in what they say, I thought maybe the experts on here could throw some light on the subject for me.  I'm really sorry if I have offended some of you, it was not my intention to be lazy  but I did want to get the temperatures right. Maybe I should have just done some trial and error anyway, what's a few broken beads!

Les, The kiln is brick lined and it has a manual controller not digital. I also have a pyrometer with a probe that goes in the back that gives a digital readout of the temperature ( C or F).

Sandra

[Redhotsal]

Hi Sandra,

I'm not at all offended by you - sorry if I went off on one. It wasn't you I was aiming at - it was a general rant and I was in a stroppy mood earlier anyway! Apologies - didn't want to hurt anyone's feelings.

The thing to remember about glass is that it is a strange substance - there's no one temperature that defines when a glass goes from solid to liquid for example. In fact, for Effetre although you can say it melts at around 800ish degrees - as you can poke it and it visibly distorts, it has fluid characteristics for a huge temperature range. Molecular movement - hence the ability to relieve the stress can also happen as low as 500 degrees although if you poked the glass it would appear to be quite rigid. Therefore it is a bit difficult to define a specific anneal temp. You may find that this will vary a little anyway accrding to the actual colour of the glass and the size of the object you are attempting to anneal.

Whether muffle, Paragon or whatever the kiln's main directive is to get things hot. I actually use a large ceramics kiln - but that's irrelevant. Whether the actual temperature inside the kiln is the same as the electronic readout or the pyrometer reading is of course not guaranteed.

In my opinion, the only way to test whether your beads are annealed or not is to test them with a pair of polarising filters. I believe I have gone over this before on FH so it should be somewhere in a thread. If you can't find it let me know and I will go through it again. The filters allow you to see the stress within a transparent bead. Stress lines show up as very distinct shadows. No stress yields no stress lines. Very simple to do and to me it is absolutely unequivocal evidence. I have polarising filters - I can sell you or anyone a pair for £6 inc P+P. The alternative is to heat and cool your beads very quickly to see if they can withstand temperature extremes and the third method of testing is to drop them on the floor and see if they bounce. I tend not to do this as they always roll under the dishwasher.

Anyway - if you are getting stress lines after annealing then it isn't annealling properly and I'm willing to bet money that many people who proudly say they kiln anneal their glass in a computer controlled kiln haven't actually ever tested their "annealed" beads with polarisers. If they did I would think they'd be in for a suprise because the truth is there is no prescription annrealing cycle. It does vary from glass to glass and kiln to kiln. So you do have to experiment.

If you don't want to experiment then you can take the belt and braces approach. If in doubt - soak them for much longer than an hour - you can't over anneal a bead but you can under anneal it. Raise the temp a little. I used to use 504 as that was the temp that many websites told me to use but a subsequent test with the trusty polarisers prompted me to up this to 520. Now, in my kiln, in my kitchen with my beads I don't get stress lines. But that may not be the case for you kiln, in your kitchen with your glass.

Sorry it's not any more specific than that but it's not a precise science.

[Les]

He he he .. you might have been in a stroppy mood Sal, but you did  air some valid points about the journey of learning we all undertake as newbie lampworkers..... I myself am proud to be pretty much self researched and taught in the beginning.. it's all part of the learning process.

Aaaaaanywayyy ....... kilns......

I just wondered Sandra because it took me a couple of trials to get  my kiln just right....  but as a guide, mine has a power input dial at the back that reads from 1 to 5..... mine is set to 1.5, which gets the kiln up to 520c in around 1 hour 45 to 2 hours .... i leave it to soak at that temp for between an hour and an hour and a half, then as it's brick lined, I simply leave it to switch off.. the bricks insulate enough to ensure a slower cooling period. I know it anneals at a good temp too as if it's a couple of degrees higher, the beads come out with little dinky white beards off the fiber blanket.. he he he.

Hope this helps

Les xx

PS... mine's in me airing cupboard.. lol

[Sandra]

Wow Sal, I think you are a scientist. Is that your other occupation apart from glass?    

I really do appreciate the time you've spent going through these things for me. You haven't hurt my feelings at all, I just don't want to be a nuisance, but I do want to do it right especially as some of the issues I've had with gas etc could be dangerous. I understand you getting on a soap box, I have a few soapboxes of my own!!  
Its nice to have an explanation for the differences in temperature.
These filters sound interesting, I'll check out the information on the forum. I would like to buy some please, do you have a website or how do I get them?

I have to go now, shirt to iron for hubby and puppy to put in the garden before bed.  I'll check in tomorrow for the information about buying the filters and to give you my address.

Thanks again

Sandra

Just read your post Les, I don't think I have a power input dial!!  I'll have to look!! I have a dial on the front that sets the temperature but it only has lines on it not numbers.  BUT after all the information from you and Sal I have a good idea of where I'm going so I'll give it a whirl.....its not like I have some super duper beads to spoil!!   Thanks again.

[♥♥Tan♥♥]

Isnt it nice that there is a place where newbies can come and ask questions that we can give the answers to instantly, rather than having to trawl through pages and pages of crap to get the info!!!

That is how I learnt Sal, I had noone to talk to, no one to give me advice and I wasted so much time and money in the process. I only found the Cindy Jenkins book after I had started. I wish I had somewhere like this, with friendly people who dont mind taking the time to answer questions.

HOWEVER.......its easy for newbies to ask the same questions over and over and over.....perhaps we could post a little something that says.....check these topics before asking your question.

[beadysam]

How about putting together some sort of FAQ sticky for newbies, including some of the most commonly asked questions, and commonly given answers?

[Redhotsal]

It's me again!

In reply to questions as to how the polarising thing works I thought I'd put this together for people who are not sure about annealling.

You need to get a pair of polarising filters. You can use a pair of polarising sunglasses and break them up, or the fancy filters you can get for cameras (though these can be a bit expensive) or you can use that amzing research facilty - Tinternet - to source your own, which is what I did. I thought I'd get quite a few at the same time I got mine so that I could let other lampworkers have their own. So, if you want a pair, email me and I will sell you a pair for £6 inc P+P.

In answer to a previous question - yes - I do have a website, just click on the pink beads banner at the base of this thread. And yes, I was a scientist in a previous career. Optical Physicist in fact.

They only work with transparent beads so what I normally do is make a plain clear spacer type bead every now and then and pop it in with the batch of beads that I'm annealling. This will give some indication of whether the batch has been successfully annealled or not. It's a good idea to make this spacer quite large as larger beads require more soak time at the annealling temperature. Basically if your largest bead is properly annealed then you can be sure that all your smaller ones will be fine aswell.

When you look at the bead try to sandwich the bead between the two filters. Ideally you want a source of diffuse light behind you. I'm lucky enough to have a little torch type thing which I sit the filters on, but you can hold them up to a window and use daylight. A lightbox or the "white" sky that we seem to get often in the UK - bright with a continuous cloud - is an excellent light.

Rotate the top filter with respect to the bottom one and you'll see that the transmitted light starts to go from  light grey to black and as you carry on rotating it beomes light grey again. If you look at the unannealled bead you'll see that it has a series of stripes radiating out from the bead hole - often in the shape of a Maltese cross. These will rotate as you rotate the filter. These are the stress lines. The more visible they are the more stress you have in the bead. A properly annealled bead will not display these lines at all it will just go from transparent to black as you rotate the filter.]

It really is a startlingly good representation of the stress lines that are in the bead. Polarisers are routinuely used for stress analysis of various objects. I have to say it gives me great peace of mind to know that there is a tangible aspect to annealling. It takes the guess work right out of it and is an excellent and vivid tool to demonstrate to your customers (if they're at all interested!) - especially if you compare your lovely annealled bead to some imported unannealed rubbish that they're raving about.

Just another way to show your customers that properly annealled beads are worth the extra pennies!

The pictures attached show:
Anneal 1 - Unannealed bead as seen through filters
Anneal 2 - Annealed bead on left and unannealed bead on right
Anneal 3 - As for Anneal 2 seen close up
Anneal 4 - Properly annealed beads don't show up any gruesome stress lines
Anneal 5 - Simple stress testing kit

[♥♥Tan♥♥]

  :oyouisdecleverone