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Box Casting v.s Open Faced Casting

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Box Casting v.s Open Faced Casting

Postby library » Fri Jun 01, 2018 2:14 pm

Hello,

I am having difficulty understanding why the firing schedule for box casting (as listed on the video tutorials) and the firing schedule for open faced casting (as listed on the video tutorial) are so radically different?

I am doing an open faced mould (silica/plaster) using bullseye billet. The negative space of the mould is 6" x 11" x 0.75" (with this last dimension being somewhat varied through out the work). Initially I copied the firing schedule for box casting as the annealing stages coincidentally matched up with my work. This is the schedule:

1. Rate-100, Temp-200, Hold-6:00
2. Rate-100, Temp-1250, Hold 2:00
3. Rate-600, Temp-1525, Hold-1:00
4. Rate-9999(AFAP), Temp 900, Hold-6:00
5. Rate-12, Temp-800, Hold-0:00
6. Rate-22, Temp-700, Hold-0:00
7. Rate 72, Temp-70, Hold-0:00

BUT, the firing schedule for open faced casting is:

1. Rate-300, Temp-300, Hold-5:00
2. Rate-150, Temp-1250, Hold-5:40
3. Rate-150, Temp-1525, Hold-3:00
4. Rate-999(AFAP), Temp-900, Hold-4:00
5. Rate-27, Temp-800, Hold-0:00
6. Rate-49, Temp-700, Hold-0:00
7. Rate-162, Temp-70, Hold-0:00

Could you please explain the reasons for:

1)Holding at 200f vs 300f?
2)The different holding times at 900f?
3)The reason for holding at 1250f in the open firing schedule?
4)Why the annealing time in the box casting does not comply with your "annealing thick slabs" chart?

Thanks so much :)

R
library
 
Posts: 15
Joined: Thu Oct 19, 2017 9:16 am

Re: Box Casting v.s Open Faced Casting

Postby marykaynitchie » Fri Jun 01, 2018 2:48 pm

Hi,

We would like to help you with this question, but we need more information about the original projects related to the firing schedules you posted. We have a lot of articles and videos, and firing cycles are usually recommended for a specific project with a specific kind of a mold and specific dimensions.

Please provide a link to the article or video (we have both) where you got this schedule:
Initially I copied the firing schedule for box casting as the annealing stages coincidentally matched up with my work. This is the schedule:

1. Rate-100, Temp-200, Hold-6:00
2. Rate-100, Temp-1250, Hold 2:00
3. Rate-600, Temp-1525, Hold-1:00
4. Rate-9999(AFAP), Temp 900, Hold-6:00
5. Rate-12, Temp-800, Hold-0:00
6. Rate-22, Temp-700, Hold-0:00
7. Rate 72, Temp-70, Hold-0:00


Please provide a link to the article or video where you got this schedule:
BUT, the firing schedule for open faced casting is:

1. Rate-300, Temp-300, Hold-5:00
2. Rate-150, Temp-1250, Hold-5:40
3. Rate-150, Temp-1525, Hold-3:00
4. Rate-999(AFAP), Temp-900, Hold-4:00
5. Rate-27, Temp-800, Hold-0:00
6. Rate-49, Temp-700, Hold-0:00
7. Rate-162, Temp-70, Hold-0:00

Once we are able to compare the specific characteristics of each project and method, we can try to address the differences that would require different cycles.

Thanks for your help--we look forward to helping you understand why these cycles have differences!

Mary Kay
Mary Kay Nitchie
Bullseye Glass Co.

Subscribe to Bullseye kiln-glass videos at
bit.ly/BullVideos
marykaynitchie
 
Posts: 1182
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Re: Box Casting v.s Open Faced Casting

Postby library » Sat Jun 02, 2018 12:49 pm

Hello,

Here is the link for where i got the firing schedule for open faced casting, it is posted in chapter 5 of this lesson:

https://videos.bullseyeglass.com/videos ... lncasting/

and here is the link for box casting, the firing schedule here is in chapter 8:

https://videos.bullseyeglass.com/videos/box-casting/

Lastly, my third question in my list should say:


3)What is the reason for holding at 1250f and at 1525 for so much longer in the open faced schedule vs. the box cast schedule?

Thanks for your attention :)

R
library
 
Posts: 15
Joined: Thu Oct 19, 2017 9:16 am


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