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-   -   Boro beads cracking (http://www.lampworketc.com/forums/showthread.php?t=222668)

saraconklin 2012-04-20 1:15pm

Boro beads cracking
 
Broken boro beads UGH. My story, by Sara Conklin

Substituted some boro I had on hand to work some new beads in a tut while awaiting my postman and disaster. The following photos are of 2 types of beads which I really loved, and both types cracked along the mandrel meridian, damn.

Possible problem: I drilled out the mandrel grooves; ok my husband did it, in my Zoozi brass presses. I took them from 3/32” to 1/8” which breaks the first commandment, DO NOT make your bead any thinner than the size of the mandrel. Maybe I pressed too hard BUT I did not press hard at all on bead #2, as you can see from the cross section. There is enough glass in this bead, especially the rectangular bead, which is hardly pressed at all. hhummmmmm.

2nd possible problem. Bead #2 was put in the kiln just before it began ramping down, not good. Called Mike, Mr. Chili pepper, and will make sure I do an hour annealing before ramping down. DID NOT do that with the #1 beads.

Bead 1: is the photo with many of the buggers in view. This is a NS white core, GA? silver strike 5 encasement, GA? triple passion thick stringers rolled in NS amber purple frit. Wonderful iridescent golden tones, beautiful pinky shades. I cooked the haze off the triple passion as I made the stringers. I cooked the haze off the amber purple frit on top of the stringers. Put them in the kiln for the recommended time, hummm what else?

Bead 2: single bead. NS white core, NS cobalt encasement, Momka almond nugget wraps and American beauty dots. Melted and shaped as usual.





i would appreciate any thoughts on my problem. thanks in advance. Sara

tiggybubba 2012-04-20 1:29pm

white directly against the mandrel may be your problem. Try laying a thin layer of clear then the white.

Alaska 2012-04-20 1:38pm

Have the same issue with NS white when used as a core color.

Solution is to add a wrap or two of clear and then apply the white. Other colors may also benefit from a clear core. Using Simax for the clear.

If a white that is not as dense is desired take a rod of clear (9-10 mm) and place one or two strips of NS white on each side. Then twist and use this for your core. The added clear helps with the cracking issue, but not as well as a solid clear core as it is dependent on the white to clear ratio.

Cosmo 2012-04-20 1:45pm

I have to ask....

Why use white? Both of the colors that are on top of the white are opaque. Well, cobalt isn't opaque, but in a layer that thick you won't be able to see through it.

saraconklin 2012-04-20 2:32pm

Cosmo: thought that the deep blue cobalt was too dark so i added the white
Alaska and Cosmo: will do a clear core from now on
thanks to everyone. bead #1 is the MOST beautiful and i was sad to think that maybe the glass types were fighting each other, thanks

Three Muses Glass 2012-04-20 3:31pm

It looks like there might be something else going on in bead #1. The crazing on the surface of the top right hand bead shouldn't have happened just because you didn't put down a clear wrap first.

saraconklin 2012-04-20 4:17pm

Rebecca: yeah, that baby broke in half too just after i took the photo. it looks more like a shattering effect huh? weird. will do more tomorrow with a clear base. i love this site, people are sooooo helpful.

Alaska: do other manufacturers white NOT do the cracking thing if it next to the mandrel?

Karen Hardy 2012-04-20 5:11pm

Quote:

Originally Posted by tiggybubba (Post 3971740)
white directly against the mandrel may be your problem. Try laying a thin layer of clear then the white.

This. And make sure that the bead is thoroughly reheated after you
press it - those brass presses can really suck the heat right out of the
glass.

Also stop admiring the beads before you put the in the kiln :wink:.
Tick-tock, Tick-tock, Tick-tock.

samandsha 2012-04-20 5:54pm

In place of the white, try NS Mint. It's creamy, super light and works great under color that you want to lighten without the cracking problems ;-D Samma

Bunyip 2012-04-20 7:53pm

Just wanted to chime in:

It's the white. :)

saraconklin 2012-04-22 9:40am

stayed up till midnight, said Happy New Year to myself, but the kiln was still at 500 so i went to bed. this morning i awoke to UNCRACKED beads!!! yay. the clear and then white process seems to have done the trick. i have some "mint" coming and like the idea that i can get a light canvas color in the center of the bead without the bulk of 2 layers. happy sunday.

saraconklin 2012-04-22 10:41am

here is the uncracked example



mo' better bruddah, now i just have to work on my lighting, ugh!

gmkcpa 2012-04-22 3:52pm

If NS White is too dense, use Borostix White. It's not as dense.


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