Thermal crack?

Pia Kaven · #1 2010-10-12, 7:20am

I would ofcourse say to who ever asked this and said that the crack goes along the mandrel: yes, it is thermal. But I am kinda thinking is it because I pressed my bead too thin? is there too little glass around the mandrel? It was fine when I took it from the kiln, but after cleaning I noticed the crack.

and it is on both sides of the bead. Bummer, liked it, but hey, I know how to make another one.

Anyone think if I would have a right idea about the crack?

Pia Kaven · #2 2010-10-12, 7:22am

Ok, I guess you wouldnt know if it has too little glass unless I show you... here!
Thanks a buch!

Dasi · #3 2010-10-12, 7:33am

As a rule, I make sure there is the same, or more glass on either side of the mandrel as the thickness of the mandrel.

Hope this makes sense.

pretty bead! Could you be dropping the temperature in the kiln to quickly?

I had this happen to me with a load of beads.... My controller was not working so I was manually lowering the temp and I went to fast and my silver glass beads cracked. None of the regular beads had a problem. I put the survivals back in the kiln and batch annealed them again.....

Pia Kaven · #4 2010-10-12, 7:39am

Yeah, my crunch press is the lean one, and I think for that mandrel it is too lean, I wasnt thinking. And my kiln might be the one to blame too, I have never had thermal cracks before, bu my kiln stays at 940 for half an hour, then it ramps down to 400 in pretty much one hour, and then just turns off. And I think I yesterday even skipped the half an hour garaging on the last bead, but this wasnt it, so it should have gotten at least an hour of garaging. Though, the door was opened couple times during it.

squid · #5 2010-10-12, 8:06am

It doesn't look too thin to me, but you do have to reheat that thin side nicely to make sure it's good and warm before you put it in the kiln.

jamie lynne · #6 2010-10-12, 8:23am

Does it go through the ivory, and it's just hard to see? Is that Juno? Looks like Juno... and that has compatibility problems with some clears... and some ivory....

Hayley · #7 2010-10-12, 8:45am

It looks like incompatibility cracks to me - the cracks don't line up, some are not straight, and they only happens on the transparent. What glass is that?

Pia Kaven · #8 2010-10-12, 8:49am

Yes, it is Juno, and it is on effetre dark ivory! I dont see any cracks in ivory, but on both sides of the bead, right in the middle where the mandrel is, just on juno... but it does seem to line up.

Hayley · #9 2010-10-12, 8:53am

Pia - the little cracks are not quite aligned in your picture . . . where the swirl is and the bottom crack where it looks like it's split off a bit too. And if they don't affect your base bead and only on the Juno, they are 100% incompatibility cracks.

jamie lynne · #10 2010-10-12, 8:55am

Holy shit. I was actually right! I'm going to go mark this one down on my calendar.

squid · #11 2010-10-12, 9:07am

Oh yeah, Juno and Dark Ivory - I have had nothing but trouble.

Pia Kaven · #12 2010-10-12, 9:42am

Well, crap! I really liked it! I am glad now I asked before wasting more of it!

Pia Kaven · #13 2010-10-12, 9:43am

Thank you all!

Pia Kaven · #14 2010-10-12, 9:59am

Quote:

Originally Posted by Hayley

Pia - the little cracks are not quite aligned in your picture . . . where the swirl is and the bottom crack where it looks like it's split off a bit too. And if they don't affect your base bead and only on the Juno, they are 100% incompatibility cracks.

Yeah, I think you are right! Thats what I started to think too, when I noticed that the Ivory doesnt seem to have any cracks. But I so wanted it to be a thermal one... dang it! Now I am really glad I had some feed back... otherwise I would have tried another one!
But I am still sad that I cant re create it... liked it!

jamie lynne · #15 2010-10-12, 6:52pm

I don't usually put silver glass over ivory, but because that is how Jenny got those awesome reactions on the product page, I tried it. I got the same kind of cracks, Pia. Maybe someone should let Paul and Jenny know that that is a lethal combo, so they can take that off of the product page.

Pia Kaven · #16 2010-10-12, 10:13pm

I know, I was so excited when I realized that I had both those glasses, I was thinking that now Im gonna make something cool. And as soon as I made it I loved it, and taking it from the kiln, thought that after years of not posting anything for sale, Im gonna do it now.... well NOT! Disappointment was huge! Oh well, I will get over it, and will find something else cool... hopefully!

tracidawn78 · #17 2010-10-13, 1:05am

Juno + Ivory = Bad

Juno + Ivory + Clear = Super Mega Ultra Uber Bad

jamie lynne · #18 2010-10-13, 5:05am

Tacki your pictrure isn't there!

Is it the one you showed in the BR?

ETA: now I see it.

Kirima · #19 2010-10-13, 5:08am

Pia, did you use clear glass on top of Juno? Juno prefers TAG Clarity. I've also been playing with Juno lately, and here is a group-shot of all the test-beads I made. Juno seems to be a diva and she doesn't like any deep encasing. I really love to use Juno for dots with TAG Clarity dots on top of the Juno dots. It might help to use her sparingly, fallowing the 10% rule we'd use for frits of a different COE? If worked too hot or for a too long period of time, Juno might fade and turn light grey, so I did try to work cooler and fast. I hope this helps?

Pia Kaven · #20 2010-10-13, 6:42am

No encasing at all in my picture. Traci dont you just friggin hate that. That would have been such a pretty bead... Though since I didnt know yet how to work it properly I didnt get as pretty blues... But I have decided too that dots or little details must be the way to go. My dotted bead was the only to survive, but it was pretty blaaaah. You Martina on the other hand, have cute collection pretty beads there.

Dasi · #21 2010-10-13, 1:09pm

I also think you could benefit from a longer annealing cycle. Hold at 950 is fine. Take the kiln down to 850 over and hour, hold, and then 750 over another hour for a short but safer ramp down.

Hayley · #22 2010-10-13, 1:41pm

Quote:

Originally Posted by Dasi

I also think you could benefit from a longer annealing cycle. Hold at 950 is fine. Take the kiln down to 850 over and hour, hold, and then 750 over another hour for a short but safer ramp down.

I agree with Heather. You should ramp down from annealing temperature to strain point (840F for Effetre) no faster than 100F/hour. To be extra safe, I also ramp down to 700F at 100F/hour.

Kirima · #23 2010-10-14, 4:18am

I do agree with Heather and Hayley, my annealing cycle is similar to Hayley's, and it's optimized for pretty large beads as well.

Pia Kaven · #24 2010-10-14, 6:31am

I will try that too... Been wondering sometimes about my annealing program, this was the first bead to crack in 8 years... Except few months ago obvious incompatibity cracked a set. The program was straight from the manual booklet for effetre, but I did think it ramped down really fast. The re-programming is going to be a headache though...