Ok, I'm stumped. Silver color trouble.

[JetAge Studio]

I had pretty good luck with my beautiful R4 color Michelangelo when I first got it, but then I started noticing that much of the color was washing out. Not sure why, I started doing systematic testing. I made 3 small round beads on separate mandrels that each had a black core, then the Mich, then clear encased. Had fantastic color before going into the kiln. I placed the beads throughout the kiln, one in the middle, one on the left one on the right of the chamber. I did a first run test with how I normaly do beads, I usually pop my beads in the kiln a little glowing still. Ran my schedule as usual. My color washed out, except for one area on the bead, which is a beautiful purple.
I recently read the help thread about Terra turning brown..etc from AKDesign (thanks for your info!!) and thought for my next test, I would let the core cool till it did not glow anymore, and try to equalized the whole temp of the bead before it went into the kiln. I also adjusted my annealing temp a little lower to around 930. My pyrometer is not the best, so the temp is approximate. Bead color was really beautiful going into the kiln. I also only held the beads at garage temp to just under 900 for 15 minutes each (again I made beads on 3 separarate mandrels), so they weren't garaged more than a total of 1 hour for the one that went in first. In this test, I also made a bead of Picasso, just to see what would happen to it. Coming out of the kiln, Mich had the same purple spot, which I discovered was on the BOTTOM of the bead, facing away from the lid and the elements.
Is this an "a-ha" moment? I dont know. I'm thinking I need to buffer the top of the beads, but how should I do that? My kiln is a small JenKen that has a single row of elements at the top of the walls (not on the lid), and a top lifting lid. Beads rest on a shelf with a bead rest about 4 inches below the elements. I have some fiber blanket I could try to place over the beads in the kiln to buffer from the elements. Does this sound right? Buffering wouldn't cause any other problems with heat distributions would it? I'm trying to wrap my brain around this one, but I feel like I'm missing something. Anyway, here's a pict of my tests. The first test bead, is on the top of the mandrel with 2 beads on it. The second bead on that mandrel was the cooling test from last night. (by the way, I did DaVincci II in this test and it looked like poo too.) The mandrel on the right is Picasso which the color stayed pretty true to how I remember it went in the kiln. This is also the color I got Mich to strike prior to going into the kiln. It's a very velvety rich blue.
Any other suggestions for me to try would be great. I'm trying to take a scientific approach, so help me try to figure this one out!! :???:
Thanks all!!
Renee Wiggins
JetAge Studio

[squid]

Most likely your kiln is actually hotter than what it says it is. Read this thread :

http://www.lampworketc.com/forums/showthread.php?t=49037

I know it will seem like a LOT to slog through, but it should help you. I had a similar saga to what you are going through and this thread documents how I solved mine. I also have a Jen Ken :)

[JetAge Studio]

Squid, Thanks for chiming in so quickly!!!! I know you've helped a lot in the past with this, so I definitly appreciate your link!

Maybe it's a JenKen thing?!

I'll read the thread while I'm at work, heee, heee,heee!

[squid]

Squid, Thanks for chiming in so quickly!!!! I know you've helped a lot in the past with this, so I definitly appreciate your link!

Maybe it's a JenKen thing?!

I'll read the thread while I'm at work, heee, heee,heee!


It might be a jen ken thing - one of my fixes was buying a lower power coil from Randy at Jen Ken. It heats a little slower, but it eliminates the huge spikes in temp that the higher powered coil had. It made a HUGE difference!

[squid]

Oh and even after changing out the thermocouple/pyrometer/coil, I still have to set my kiln 100 degrees lower than what I want. It is 100 degrees off of what it says it is. When I started, it was 200 degrees off.

[JetAge Studio]

I kindof feel my kiln is running hotter than what it says too. Thanks for your tips, I will look into all of this!!
Renee

[JetAge Studio]

Hey Squid,
So I've read through most of the thread, and you really did go through hell getting things to work!!!
I have a few more tests to run before I change out parts in the kiln, but could you tell me:
a) How's the beads coming out since your last post in that thread? Still good? Any other discoveries?
b) I saw you had many annealing temps, but in the last post, your annealing target temp ended up at 925. Is this still working for you too? I lowered my temp too, and while I'm still fairly certain that my pyrometer is not as accurate as I'd like, I'm reading somewhere in that range on mine as well. Maybe I'm in the ballpark.

I definitely get those temp spikes in my kiln too, so that makes total sense, I may have to get my kiln up to garage temp, and hold on low to equalize before I get the beads in there to avoid the spike. Somewhere to start. I'll read more tonight.

Thanks so much for the info!! Given all the different factors, kilns, working habits, glass habits, this one is definitly a challenge!!

Renee

[squid]

I think you saw my post in the other thread about my terra recently, but all my other colors are fine at 920. I let my kiln ramp up and sit for about 15 minutes to get temps equilized well before I start work. The terra I had overstrike last night were the first ones I made, but they were only held for an hour or so before it went into the anneal cycle.

[JetAge Studio]

Ok, second experiment was a success!!
Here's what I did:
Before turning on the kiln, I put in a double layer of fiber blanket. Then I got the kiln up to temp and equalized the temp to hold at around 875. Once that was stable for 15 mins on low (I dont have a digi-controler), I made my test bead.
I got the bead to strike the color I needed, cooled the core and equalized the bead's surface with the core temp. Poped the bead into the kiln laying it in the blanket so it was well insulated from the elements. I then took the bead up to around 925, and held for anneal for 15 minutes.
The bead came out with color all the way around! Great purples and blues!

My thinking was that the glass was getting too hot "facing" the elements, and causing the glass to opacify, and obscure/change the color. This happens to me sometimes when I fuse certan colors at too high of a temp for too long. When this happens, I dont think the color is "burning out", because the kiln temps aren't getting high enough to actually "burn" the color out. When I over heat Mich, or Terra with the torch, the glass goes dark transp. brown, here the beads are going hazy grey, or poo brown, I think it's just opacification of the glasses. I guess it's called overstriking too.

This is just my theory, I have more research to do. But hey, this makes progress!! Buffer the glass!

Renee
JetAge Studio

Here's a few picts of the successful bead, and the fiber blanket in my kiln.

[squid]

with silver glasses, the higher heat causes the crystals to keep growing after you have struck to the color you want. The additional striking is the darker colors you are seeing.

For your next experiment, perhaps try the same temps again but without the fiber blanket and see what you get. :)

[nagibeads]

ooooh! Pretty!!

[JetAge Studio]

I had an interesting email from R4 Ron, he says Michelangelo, DaVincci etc. glasses strike in an Oxy rich flame. I got my Mich to strike in a heavy redux, that's the color you see above! Curious, what does everybody else do?
I'll be sure to let you know Squid what my next results are! :)
Renee

[squid]

I think the Mich is a reduction glass. Dali is a oxy rich glass, as is terra, DV2, Van Gogh, etc.

I may need to recheck on the Mich, but i could have sworn I reduced it.

[squid]

I just went back and reread your post about getting a dark brown bead and it opacifying. This is actually what you are supposed to get. The dark brown is the step right before the colors start to develop.