Sinter Beads

[user name]

Are they all created equal? I realize there are size differences, but how about material? purity?

Is one as good as another or is there a quality difference? The prices vary wildly; without much search, Ive found one resource selling a 200gm bottle for nearly $300, and another for the same size down under $90.

I hope it wasn't a secret, but its also been suggested that Bego Korox 250 works well; that would certainly be the lowest cost way to go, unless they don't last?

With my Dekema oven, Ive been using a Mullite tray so no beads have been used. I know that Mihm-Vogt has an alumina tray, also no beads needed, but was told its just for occasional use and I should stick with beads.

Thoughts?

 

[rc75]

I sell sintering beads 200 grams for $30. 1mm or 2mm contact me if you have any questions.
Sintering trays 85mm or 95mm round 1 1/2 inch deep with lid $35.

 

[JMN]

Are they all created equal? I realize there are size differences, but how about material? purity?

Is one as good as another or is there a quality difference? The prices vary wildly; without much search, Ive found one resource selling a 200gm bottle for nearly $300, and another for the same size down under $90.

I hope it wasn't a secret, but its also been suggested that Bego Korox 250 works well; that would certainly be the lowest cost way to go, unless they don't last?

With my Dekema oven, Ive been using a Mullite tray so no beads have been used. I know that Mihm-Vogt has an alumina tray, also no beads needed, but was told its just for occasional use and I should stick with beads.

Thoughts?

May be talking through my hat here, but my limited understanding is the beads are for absorbing stuff so it doesn't foul the elements and to provide minimal point contact size for color stability/even heating/even air contact as opposed to a large area of the crown sitting flat against the riser tray. This is the same reason for having lids on the trays, reduction in escaping element fouling components, reduction of chance of something getting in the sintering material from fouled elements.

Bob Cohen's book, free download at CAP, goes into this better than I can.

 

[RileyS]

Been rocking same beads for two years I just barely changed caused I'd notice little white dots on crowns after sintered. Not sure where I got them. Does that help?

 

[user name]

Been rocking same beads for two years I just barely changed caused I'd notice little white dots on crowns after sintered. Not sure where I got them. Does that help?

Id sure like to know what they are.

 

[corona]

ive gotten the white dots on my crowns every now and then . . Im not 100 % convinced they are from the beads ... Im thinking they might be coming from a contaminent in the liquids we use to color them ? My sinter oven doesnt require beads ....been using my sinter oven since 2009 and sintering without beads for that long . Maybe 8 or 9 have come out with that white spot since 09. Always about a mm in circumference and completlely rounded.

 

[Sevan P]

I have the .5mm beads from Talladium and I have yet to run through my first bottle. I have a second one just for when I run through the first one. I would only use the small beads, they allow you to place more units in your tray and tighter together. The larger beads slide the units around and if they get in you abutments good luck getting them out, the small ones come right off.

 

[Taylor Stutz]

Been rocking same beads for two years I just barely changed caused I'd notice little white dots on crowns after sintered. Not sure where I got them. Does that help?

i think the white dots come from a mess up in the manufacturing of the zirconia, in the colloidal or pressing process i think it doesnt set right. So what we get in the puck of zirconia is a non translucent spot where the powder maybe is much thicker and will not look similar to the rest of the zirconia around it that did set up right. I dont know, its been a theory of mine, because i see them in my teeth sometimes as well, but i cannot ever find one similar variable, from beads to oven to different zirconia brands.

 

[CoolHandLuke]

the white dots are spots where heat has trapped, causing oversintering.

never mix bead sizes.

never submerse units in beads. lay them on the top of the beads.

this way you can trap a layer of heat, getting a slight differential, enough to cause nicer results at lower temperatures. sintering at 1400, youll trap a few dozen degrees in the beads, so the differential will be something like 1380 in the beads and 1350 or 1360 in the surrounding air. a good little diference like this can be a benefit to processing naturally not nice zirconias, like bruxzir.

wont help much in cubex or xt.

 

[zero_zero]

the white dots are spots where heat has trapped, causing oversintering

Right...could you elaborate how exactly is that possible, localized to a particular spot, often not in contact with the sintering media ?

 

[CoolHandLuke]

distribution of beads.

like the surface of the sun. its all helium gone to plasma, but some spots exude flame spurts hitter thhan other areas.

same principle.

its just too much differential.

use less beads.

 

[zero_zero]

like the surface of the sun. its all helium gone to plasma, but some spots exude flame spurts hitter thhan other areas.

It makes so much sense now...

 

[CoolHandLuke]

i never said i was sane.

 

[RileyS]

I do an even one layer of beads. And every once and awhile a perfect circle of white shows up in the crown

 

[zero_zero]

I don't use sinter beads, only 250 um Alox blasting media....do change it after about 50-60 cycles or whenever white spots start to show...the beauty of it that it starts very faint, never ruined a crown