bullseye on bullseye compatibility issues?

ChaseDesigns · #1 2006-10-28, 10:14am

HUmm, I just made two sets yesturday, well actually three and two had issues cracking issues.

Both that cracked were pressed beads where I used aqua tint to encase an opal color. One set was steel blue and the other was turquoise. They were both florals and the cracking occured in different placesd on the encasing, not the florals.

I make pressed bullseye florals all the time and never have issues. I know to put them in glowing.

We anneal at 950, but it runs a but higher than that, cause our kiln is a real small one, but I am wondering if anyone has ever had compatibilty issues with using straight bullseye colors before?
Or if maybe some colors need that higher annealing temp?

Any thoughts would be helpful. We have only been using bullseye for about 3months, although daily practically and haven't has issues to far.

Kalera · #2 2006-10-28, 10:17am

I have not had this problem, but I can mess around and see if I can replicate it. I wonder if you emailed Bullseye if they would have any input for you?

ChaseDesigns · #3 2006-10-28, 10:19am

Thanks Kalera. I will email them and ask. You never know.

pam · #4 2006-10-28, 10:40am

I can honestly say that I have never had incompatibility issues with Bullseye. I have had cracked beads at various times, and it is most likely, I have figured out, due to my working it to cold. Even though I reheat before putting it in the kiln, if I am concentrating on an area and let it get too cold, it will come out of the kiln cracked (even if I didn't see it going in).

ChaseDesigns · #5 2006-10-28, 10:47am

Thanks for your input Pam, but I think a few of them cracked after they were taken out of the kiln. 10 of 11 beads I found cracks on. While the six of the other set where perfectly fine.

In fact on one set Greg found the cracks while cleaning them, then as I inspected the first set he cleaned they started to form. One crack was real obvious. I think he would have seen it.

ChaseDesigns · #6 2006-10-28, 10:49am

Could be annealing temp. We are going to run some tests.

Kalera · #7 2006-10-28, 10:50am

That really sounds like extreme incompatibility.

Is there any possibility, any at all, that one of the rods could have been something other than Bullseye? Do you have Moretti in your shop at all?

Which color combination had the worst cracking? I can play with it on Monday.

MaryBeth · #8 2006-10-28, 10:53am

I've never had these issues but I soak betweem 970 and 980. According to BE's tech notes on page 4 the minimum soaking temperature is 960. Maybe your kiln is not running quite as hot as you think it is.

The blues may require the higher end of the soaking temperature. I often encase Egyptian blue and I never have any problems. So - bump up your kiln temperature a little - it won't hurt

Here is the link to the pertinent tech notes:

http://www.bullseyeglass.com/pdfs/te...chNotes_04.pdf

ChaseDesigns · #9 2006-10-28, 10:59am

We do have moretti, but it was definiately bullseye. I even double checked the rods I was using last night. Yep def bullseye. Actually the turquoise cracked first, but both were pretty bad.

Thanks Mary Beth. I will read that. Greg is resetting the kiln today, for a higher annealing temp. We walk a fine line cause he does marbles too and we don't want flat spots.

ChaseDesigns · #10 2006-10-29, 11:14am

Well, I did another test on the turquoise bead. I made just one yesturday, with the aqua tint encasing it. We set our annealing temp at 960, to anneal for two hours before it ramped down. Cracked again. I just don't see how this isn't compatibility.

I did make two ther bullseye sets after that test bead and they are fine, so I know it can't be a kiln issue.

Time to contact bullseye I guess.

squid · #11 2006-10-29, 11:18am

yeah, that sounds pretty suspect. I will be interested to hear what they have to say.

Kalera · #12 2006-10-29, 11:21am

It does sound like incompatibility to me... especially the after-annealing cracking. Just to make sure I'm using the right glass... it was 0116 opal turquoise and 0146 opal steel blue, encased with 1808 aqua blue tint? I might be able to mess around with them today. Was it a thick or a thin encasing? I can do both, and try both pressed and round.

What's your ramp-down rate?

ChaseDesigns · #13 2006-10-29, 11:38am

Yep Kalera, those are the colors. We do hold our kiln at 940 before the annealing schedule starts. So that bead was in the kiln for four hours before we started the schedule.

960 two hours
ramps to 870 for 3.15 hrs
Hold at 870 for 45 minutes.
then off.

It is pretty light encasing. 18 mm pressed button (cattwalk press) bead. I did put some flowers on top of the encasing. But that doesn't seem to be part of the issue. But the flowers were turquoise opal 0116 with turquoise transparent 1116 over it. oh and some vine cane, also doesn't seen to be part of the issue either. Same cane I have used on 100's of bullseye beads.

Geneva · #14 2006-10-29, 12:20pm

Maybe your hold temp is to low. Normally holds are above the annealling rate. In our classes we explain it in a very simple form. Glass that sits at 1000* and above is in a fairly nutural statis and you are able to do many things with it.
The melecular structure is like a pile of fish scales piled up on a table. As you sit at your annealing temp these scales flatten and reallign themselves to look like they were still on the fish. If you are holding below the annealling rate you have already flattened the scale down out of allignment and when you come back up it is harder for them to realign properly. That is why some larger pieces crack when they are batch annealled and people that do fusing have to anneal after each step with mutiple fusings. You are releaving stress when you anneal and many time it is what you actually do to the glass that can add more or less stress.
Hope this helps, I'm alot better at explaining it in front of a class, I've alway had it edited by someone when it goes in articles.
Geneva

ChaseDesigns · #15 2006-10-29, 1:24pm

hummm, well, maybe the hold is too low. But Greg makes 2 inch marbles with bullseye with the hold at 940 and we have never had this issue. If we held at 1000 he would have flat spots on the marbles. No way is that possible.

Chuckie · #16 2006-10-29, 1:30pm

My hold temp is 968. I also ramp all the way down to 750 at 100 degrees per hour before shutting off the kiln. Maybe you're cooling them off too quickly.

Char

CraftymissKim · #17 2006-10-29, 2:29pm

What goes with bullseye Please list Brands not numbers thank you all so much.

ChaseDesigns · #18 2006-10-29, 2:47pm

Kim, bullseye is 90 COE. You should only use bullseye with bullseye

Chuckie · #19 2006-10-29, 3:03pm

Uroborus makes fusible sheet glass in 90 COE, but no rods.

Wasser Glass is 90 COE, but it is also flat glass and is softer than BE.

Gaffer casting glass is 92 COE and some colors can be used with BE, but you should test it for compatibility. Careful not to get the Gaffer 96 COE furnace glass rods.

CraftymissKim · #20 2006-10-29, 3:11pm

Thank you

Kalera · #21 2006-10-29, 4:38pm

I hold at 968, no problems normally.

It's possible, if the hold temp is the issue with this color combo, that it's only a problem with pressed beads. Marbles have incredible structural strength.

hotfire210 · #22 2006-10-29, 10:44pm

Quote:

Originally Posted by Travelin'gal

960 two hours
ramps to 870 for 3.15 hrs
Hold at 870 for 45 minutes.
then off.

I hold and anneal at 968 for one hour, then ramp down 150 degrees an hour to 350, then off. I've never had a problem with cracking when using Bullseye...I believe the glass is most susceptible to cracking (thermal shock) between 500and 850 degrees. Bullseye has some wonderful tech notes on their site:
http://www.bullseyeglass.com/pdfs/te...chNotes_04.pdf

Kalera · #23 2006-10-29, 10:53pm

Seems to m that the strain point for Bullseye is between 920 and 820 depending on the color... so you'd want to have your kiln ramp down pretty slowly to at least 820, and preferably a couple hundred below it, before shutting off. You can still get thermal shock if it cools too quickly after passing the strain point, too. I hold at 968 for an hour, ramp down slowly to 850, hold for 15 minutes, ramp down slowly again to 450, then shut off.

I have some beads in there now, I'll let you know how they hold up after cleaning them in the morning.

lunesse · #24 2006-10-29, 10:55pm

I hold around 968 as well. I had 3 beads crack yesterday with black, aqua, ...whatsit, light violet? There was some foil in there. They cracked AFTER they were out for a few hours.

Kalera · #25 2006-10-29, 11:05pm

So wierd! Which aqua did you use? Was it the tint? I make encased beads with foil and aqua a lot, now I'm nervous.

ChaseDesigns · #26 2006-10-30, 8:25am

honestly I don't think it is our ramp down time. I know marbles are very stucturally sound, but we have experimented quite a bit with that. And they will crack if brought down too fast, and they are not quiet about it. Our kiln is brick and it takes a lonnnng time to cool off. We never open it before it is under 100 degrees. As it is now it takes over 10 hrs to totally cool.

It really is just this color combo I am having issues with. I guess now I am thinking it is compatibility or the chance it might just be pressed beads and this particular color combo that maybe the annealing schedule doesn't work for.

Kalera thank you for the tests, i am interested in what you find. The beads I made the other day are cracking in all different places. I mean usually when I get thermal cracking they crack right down the middle, in half. These are cracking in all different places. One of them is even cracking totally opposite from the mandrel hole, up the sides of the pressed bead on the edge.

Lunesee, I am also interested in what color aqua you used.

Kalera · #27 2006-10-30, 4:00pm

OK, yesterday I made 8 beads... thinly encased pressed ones and more thickly encased round ones. I cleaned them this morning, and so far they all seem to be fine.

I am wondering now whether it is possible that you either got a bad batch or a mislabeled batch? The cracking really does sound like compatibility issues, and bad ones... not thermal issues. Have you tried the aqua with any other colors? My bet is on the aqua as the source of your problems.

lunesse · #28 2006-10-31, 12:33am

I was actually using non-tint aqua, now that I went back to look at my rods. So that counts me out of this little test....

Hm. I might try again tomorrow and see.

ChaseDesigns · #29 2006-10-31, 7:16pm

Hey thanks for the test Kalera. The aqua tint is a new batch that we just got less than a month ago. I will try it with some other colors when we get the studio back up and see what I find.

anne225 · #30 2006-11-01, 1:33pm

Jus for another 2 cents worth...
My kiln works on a contoller and the whole thing was preprogrammed by Arrow Springs. Great brick kiln, I might add.
I use BullsEye all the time and I have never had a crack like you are describing. There is a batch in the kiln right now and it starts at around 960 and goes down slowly.

Since I do not own any aqua tint but have tons of the other colors and mess around with them all I might agree that it may be the tint and its reaction with what you are using it with.

Please let us know. I was actually thinking of starting the tint collection...hmmm, maybe not!
Anne