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I've got a hi fire in the kiln right now and was wondering what the 1.5 to 2 hour hold at 1700 is for. Is it just to let bubbles surface? Is the glass continually moving at these temps?

The reason I'm asking is because I've been watching the surface of the melt for about an hour at 1700, and it's "as smooth as glass". No bubbling happening at all. Is the glass moving, but just apparent at the surface?

...Kelly

Yep, it's moving. I hope you are looking at the glass with protected eyes. That's the fastest way to burn your retna.

Amy

I understand that when the "batch" is melting, there's a great deal of movement happening. What I don't know is what's causing it to move after everything has settled out. Is it that at these temps, the glass is sorta boiling, though if that were the case, I would think there would be alot or at least some bubbles coming to the surface.

Just Curious Girl.

I think it has more to with the difference in viscocity between the colors than bubbles, which I do believe play a part as well.

Amy

Thanks Amy.

The other night I was making garlic toast in the broiler, and my son mentioned that it wasn't good to watch the red hot coils in the oven. Your comment about protecting your eyes when looking into the kiln made me think about the broiler. Was he correct?

Yeah probably. Why risk it or I guess plan on going blind...

I looked at my high fire once and couldn't see anything, so now I never look at it until I pull it out of the kiln. It's not like you can do anything about the outcome anyway.

Amy

Lynn Bishop wrote:The other night I was making garlic toast in the broiler, and my son mentioned that it wasn't good to watch the red hot coils in the oven. Your comment about protecting your eyes when looking into the kiln made me think about the broiler. Was he correct?

Hey Lynn,

Son good! Son smart!

I don't think any radiant heat source is good to look at.

I don't know how bad it is, but it's some degree of not good.

Brock

For those who may be researching Hi Fires - -

The slab I removed this morning had quite a few small to med. bubble pits on the surface. I only fired to 1700 for about 45 minutes or thereabouts. There wasn't as much movement as I'd seen on those that I'd fired for 1.5 hrs +. (There's very little pitting on those that were fired longer).

As for didymium eye protection, nope, wasn't wearing them when I was peaking. I have a pair in the shop, just haven't taken the time to locate 'em. I don't stare at the molten mass, but I do take long glances. You're right tho. I should be more cautious.

KAG wrote: As for didymium eye protection, nope, wasn't wearing them when I was peaking. I have a pair in the shop, just haven't taken the time to locate 'em. I don't stare at the molten mass, but I do take long glances. You're right tho. I should be more cautious.

I was given to understand that didymium glasses were used for protecting the eyes while working with the flame of a bead torch, which gives off some kind of fumes or something. Can anyone confirm that they are in fact good for protecting against radiant heat from the kiln?

I use green welder's glass for looking into the kiln, but they're so dark, I can barely see anything.

Cheers,
Suzan

You can get different strenghts of protection. I got some light duty ones from Aura Lens.

Amy

The AUR-99 lens is a good choice.

http://www.auralens.com/gwlensinfo.html#aur99

Ron

Do either of you have the bifocal Aura lenses? I was thinking they might be helpful-

Nope, I don't wear glasses.
Amy

kelly alge wrote:Do either of you have the bifocal Aura lenses? I was thinking they might be helpful-

I have the bi-focal didymiums and they are HEAVY, but they work just wonderfull.
Jim

Didymiums are useful for reducing the yellow sodium flare that torchworkers see, but it's the infra red that is a problem for the eyes lens. Make sure that the glasses you use are rated specifically for IR protection.

kelly alge wrote:Do either of you have the bifocal Aura lenses? I was thinking they might be helpful-

I have the 9302 Large Economy frames that just fit over regular eye glasses. For occasional use they work fine, but custon fit frames would be better for extended use.

See the second frames on the attached link.

http://www.auralens.com/safety.html

Ron

I don't wear glasses either, but maybe I misunderstood the catalog listing... I was thinking the Aura bifocals were just split lenses with 2 degrees of protection- look straight on and get the most, glance up and get a lesser protection, more viewable color, etc.
Sounded really good to me!

If you are going to use a welders eye protection, get the AMBER face shield, not the green. That way you will be able to see more color.

OK, now I'm confused. Welders glasses are usually green. Aren't amber filters generally for ultraviolet, not infrared? I use No. 3 welders glasses for looking in the kiln (at least they are on the table beside my kiln and really I do use them when it's not just a quick peek), not my lampworkers glasses, even though they are an enhanced didymium with some IR protection. The No. 3 glasses aren't very dark so you can still see what's going on, I'm hoping they are enough protection, and I think? they give more protection (and a WHOLE lot cheaper) than AUR92 or equivalent lampworkers glasses. You spend a lot of money on lampworkers glasses for the sodium flare filter which you don't need for the kiln.

I'm sure one of you scientific types has done the research and could tell us exactly how much infrared each type filters.