am i just over thinking or what? kiln question...

[Batou]

i was getting ready to program my paragon f-130 for the first time and i have run into a mental roadblock. i know the start at 1050 deg. and then 925- to 725 etc for X amount of hours based on thickness. where i hit the wall is, when i'm programming it asks for the rate(temp change per hour). i can make it max rate to get to 1050 quickly but what should the rates be as it goes down to 925 and further down? should i just set it at max? i'm confused....
:bangHead::bangHead::bangHead::bangHead::bangHead: :bangHead::tantrum:

[Glass Pyro]

I asked the same question when I got my f130 and this is what i do for everything i make now. I ramp up at 700 deg. F per hour(I heard it was not good to ramp up at full) + this gives me time to make somethings, if I am not using my garaging program. Then I ramp down at max and hold, and that usually takes long enough.....and I have not had any problems yet. Hope I helped.

[CripSkillz]

this was on the northstar user manual but there site isnt working for me, but I can still get it here, maybe you can too

like page 4 http://209.85.173.104/search?q=cache:dPu84vFv9hAJ:www.northstarglass.com/usersmanual.pdf+northstarglass&hl=en&ct=clnk&cd=2&gl=us&client=firefox-a

[beachglass]

for thicker stuff i ramp down at 60 deg an hour to 950, then hold there for 45 mins....i dont think you have to worry much about ramping down under 950 as i think this is the strain point...

plus if the kiln has been on a while the bricks will hold the heat so if you turn the kiln off at 950 it will still go down slowly

[Big Jay]

If you can get a second pyrometer shut your kiln off at 1050 and watch how the temp falls. I found out my kiln cools slower then most suggested ramp rates up until about 2" thickness. Even with one punty door open. (Aim 9169 kiln).
So if you never do anything over that I'd say just set your ramp to hit the strain point and hold as recomended then to shut off.
I set my program up for about 2.5" material based on Contempary Lampworking recomendations. And only run it when I have something that has a high probability of stress or its that thickness. That means for my daily hollow stuff or small pendants I usually just shut off the kiln at the end of the day. Even though I have a 4 program controller from auralens allowing me to create 4 seperate ramping programs.
The second alternative is if you never make anything of that thickness is to set your program up as a striking program.Garage at desired temp then run program to ramp to strike temp, hold for desired time, ramp to strain point, ramp to 0.

[Greymatter Glass]

There is a chart in Contemporary Lampworking that has the Rsc (ramp, slow cool) values for different thicknesses, but it can vary from manufacturer to manufacturer. The viscosity of the glass, and the use of non-equal α glass will change the numbers.

The rate I use for everything up to 2" marbles as my general program is set to 60°F/Hr. That's nearly double the recommended 1.something per second listed on the table for a 1.5" thickness.

It's funny, no matter which controller you use you still can't win. I was sitting here last night trying to convert °/hr to minutes to temp for the Digitry GB-1 on the LGW kilns. Overall I think the GB-1 is easier to program, if you know the length of your ramp down by heart, but otherwise you have to calculate it, otherwise the Bartlett based controls are much easier. (seems to me that Skutt, Paragon, Evenheat, and Olympia kilns all use the same Bartlet controller with a custom face plate...could be wrong)

-Doug

[Batou]

thanks for the info. guess i'll be tinkering and trying. but isn't that the fun of it?