Lampwork Etc.

Lampwork Etc. (http://www.lampworketc.com/forums/index.php)
-   Tips, Techniques, and Questions (http://www.lampworketc.com/forums/forumdisplay.php?f=29)
-   -   Cracking beads down the mandrel (http://www.lampworketc.com/forums/showthread.php?t=253242)

Donna T. 2013-10-09 3:08pm

Cracking beads down the mandrel
 
I'm not new to bead making but the last few months I've had a rash of focal beads cracking down the mandrel. I just took a beautiful bead off the mandrel and immediately it got a running crack on both sides following the mandrel.

Could it be the bead release? I've tried several lately and still having cracks. I've had the kiln checked out and it's working properly. I've got cracking on simple beads and elaborate beads.

Today's bead was the transp orange/ clear/ Aurae/ clear combo. It was beautiful. :pout:

But I've got simple beads cracking too. Any ideas. I'm frustrated.

KJohn 2013-10-09 4:43pm

Ugh. What kind of releases? Mandrels? I'm sure you've gone through the easy fixes already.

allicat 2013-10-09 5:35pm

You're not using BlueSludge are you? If so, do a search in here; there were some concerns raised regarding it a little while back.

Alli

wendbill 2013-10-09 5:42pm

Is it a problem with pressed beads or all of them?

Are you heating both sides of the bead before you put it in the kiln?

AVTrout 2013-10-09 6:12pm

I find that if I make my beads too thin when I press them, then 2 things will happen. Either they crack when I'm removing them from the mandrel, or they come off fine, but when I use the Dremel to clean them, the next day they always are cracked in half. I think it has something to do with the super fast vibrations and the thinness of the glass.

Jo Ann 2013-10-09 7:15pm

I've been have issues when I encase lauscha with vs super clear. Thought I could mix them since they are both 104 but beads crack when I'm encasing the red sangre

Eileen 2013-10-09 8:23pm

I thought we were supposed to put a clear core 1st if using the warm colors inside (yellows/orange/reds) to avoid cracking?

Anne Londez 2013-10-10 2:07am

I too am thinking if might be a shaping problem. Are you using a press of something similar to shape ?

Donna T. 2013-10-11 3:25pm

1 Attachment(s)
I'm leaning toward I'm pressing them too hot and too thin. They either crack as soon as I get them off the mandrel or while I'm cleaning them.

I am using Blue Sludge but I've actually had less cracking with it then what I was using before (can't remember what) but right now I have a mixture of several including the Blue Sludge. I'm using one from Etsy that comes as a powder and you mix water to it.

The mandrels are old so I don't think that's the problem unless there's something about old mandrels I missed.

I will make sure I'm heating both sides before putting in kiln but I'm pretty sure I do anyways.

Here's a picture of the last beads that cracked.

jaci 2013-10-12 5:56am

What a pretty bead!! So sad it craCked!

I is end up getting a new batch of blue sludge, not one crack yet.. Just an FYI. I got both blue sludge and sludge plus. Have not tried the plus yet. I'll keep you updates.

I'm wondering what the base color is here, and how thin it really is. The general rule is 'as much glass on all sides at least as thick as the mandrel' that's bare min. A bead that thin can easily break if the tiniest bit of bead release gets broken on the mandrel when you press as well. Maybe try this in clear, then look to see of any bead release shifted. I would also think that if a silver glass didn't like its base color that being so thin if would pick that spot to pop apart. So again trying just clear will also tell you if that is the issue. Don't forget to decorate in a similar fashion (with clear also) to rule out heat stress fractures. Any troubles with any other shapes?

Lisi 2013-10-12 6:35am

Try some beads with only Effetre and nothing else. Use transparent colors or clear so if they crack you will see it easier. If they still do, then it has to be the bead release. If not, then it's the brands of glass you are mixing. I've always wondered about compatibility within all the brands that are supposed to be 104 COE.

One of these days if I ever start encasing beads in clear, the colors are all going to be from the same brand. Even so, there could still be trouble.

flame n fuse 2013-10-12 11:45am

the bead in the photo does look quite thin, that could be the issue, as Jaci suggests

wendbill 2013-10-13 3:01am

There's a rule of thumb which used to be quoted, and of course I can't quite remember it...

Something about the thickness of the glass on either side of the mandrel needs to be at least as thick as the mandrel's diameter to avoid breakage. Possibly twice as thick?

Maybe someone else remembers it?

angelique_redhead 2013-10-13 4:34am

It looks like it needed more insurance heat to me. I've had beads crack like that along the mandrel when I didn't rewarm them enough after pressing. Good luck. :love: Angelique

Donna T. 2013-10-13 12:35pm

3 Attachment(s)
Here are two more examples from yesterday's session. The first one is made with Kalypso with the orange, clear, Kalypso, clear formula. I tried to make sure it was thick and not press too much but it broke in half as I'm twisting it off the mandrel. I posted an end shot to see if you guys think this is too thin. I made another bead using the same formula though it was shorter and more round and it came out fine.

The second bead is just plain Moretti white, tree is Tuxedo and dots are transparent orange. The front is fine the back has a crack running the length. It's possible I didn't keep the back warm enough while I was adding the dots.

I'm still leaning towards the bead release.

Lisi 2013-10-13 1:08pm

I think they might be too thin. Especially near the bead holes, and that's where the crack probably began and it makes sense that it would travel down the center of the bead from that start at the hole.

Are you using 3/32" mandrels? Try the 5/64" and see if there is a difference. Or use the 3/32" but press to no less than double the thickness of the mandrel on both sides. Now I'm thinking that it may not be your glass combinations at all. So maybe we should narrow it down to mandrel size and then finally, the bead release. :)

Donna T. 2013-10-13 1:16pm

Yes I'm using 3/32. Is 5/64 bigger or smaller that 3/32? I never was good with fractions.
Ok, I'm going to work on not pressing it as much and making sure I have more glass at the ends. I sure did like that first bead. :(

28676bhe 2013-10-13 1:30pm

Smaller, but not by much. I doubt if you could guess the difference by your eyes, but maybe rolling in your fingers, you could.

6/64th is the same as 3/32, so 5/64th is just a wee bit smaller.

jaci 2013-10-13 1:42pm

Looks too thin from the pic!!! That glass looks paper thin on the top. The bottom looks ok around the hole, but the top (in the pic) is way too thin. Especially if it's breaking while you are taking it off the mandrel. The twisting is putting too much stress on the thin glass. Basically, stack 3 mandrels. That's the absolute thinnest your bead should be when you squish it. (Stack dipped mandrels!!!)

....@ @ <<<<= glass as thick as the mandrel on all sides, no matter the shape.
..@ O @ Bigger mandrel=Bigger glass walls :)
....@ @

Your bead=
---------- <<< too thin!
@@O@@
..@@@

Lisi 2013-10-13 2:01pm

My measurements of mandrel diameters with and without bead release:

1/16"
with: 2mm
without: 1.5mm

5/64"
with: 2.5mm
without: 2mm

3/32"
with: 3mm
without: 2.5mm

The 0.5mm extra thickness of a mandrel does make a difference. I would try the 5/64" to make your pressed focal beads, and in your listings, you can write that the beads have 2.5mm holes.

Donna T. 2013-10-13 2:11pm

Thanks everyone. I think I have some of the other mandrels and I'll press less.

tammydownunder 2013-10-13 7:18pm

I'd put my money on the blue sludge. Can you make some test beads with different types of bead release? When I used the blue sludge, I had all sorts of weird cracking. Lentils, down the mandrel or just to the side, stubby bi-cones and rounds didn't crack but they chipped when I cleaned them.

I've been making beads for 9 years and never had cracking issues until I got the blue sludge and I was rather insulted when it was suggested that it was my bead making skills.

Elizabeth Beads 2013-10-14 6:32am

Just try a different bead release. Your beads don't look too thin to me.

I use the ABR brand bead release and love it.

glass addict 2013-10-14 6:44am

I think it may be they are going into the kiln too cold, and maybe a bit thin in the pressed area. Think of the mandrel as a heat sink, or something that sucks the heat out of your bead, which is why they tend to crack along the mandrel.

Good Luck!
Mary

yellowbird 2013-10-14 7:29am

I'm baffled how bead release could make them crack?
interesting that your white bead is only cracked on one side
fits with the heat sink the tree side would have gotten more heat.

tammydownunder 2013-10-14 1:23pm

Quote:

Originally Posted by yellowbird (Post 4432821)
I'm baffled how bead release could make them crack?
interesting that your white bead is only cracked on one side
fits with the heat sink the tree side would have gotten more heat.

When I was having my cracking issues, someone explained that it's possible for the bead release to have expansion capabilities.

Lisi 2013-10-14 7:36pm

Quote:

Originally Posted by yellowbird (Post 4432821)
I'm baffled how bead release could make them crack?
interesting that your white bead is only cracked on one side
fits with the heat sink the tree side would have gotten more heat.

That does make sense to me.

A while back in another thread I suggested that bead release could expand and that idea was quickly shot down. Actually, now I can't see how it would expand. It's ceramic slip clay, and there are no ingredients in it that would do that. Flake off maybe, but that's about it.

28676bhe 2013-10-14 9:42pm

I'm wondering IF:

The bead release cracks, leaves a bare mandrel spot (smallish), and when we try to take the bead off we cause a lot of stress trying to get it unstuck? And maybe it cracks from that?

All mine are from the mandrel acting as a heat sink, me not keeping the whole bead hot, and/or pressing it too much.

Ravenesque 2013-10-14 11:21pm

I've made beads that thin, I like to smash 8)
I'm guessing as someone else said it's a heat insurance thing since the white one is only cracked in the back.

wendbill 2013-10-15 2:54am

With pressed beads you do need to flip them and heat both sides.

I personally gave up on a kalera press because I kept failing to press evenly, and consistently had lots/ most crack down the mandrel.

It's possible that some bead releases retain more heat than others, maybe that's the subtle difference betWeen failure or not.


Which ingredient in bead release could have the expansion capabilities?


All times are GMT -7. The time now is 4:10pm.

Powered by vBulletin® Version 3.7.5
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.