Fiber compared to kiln wash

[Chris Lowry]

I've been making some thicker slabs with Spruce Pine glass that have a lot of clear glass. They are turning out very clean except for a light dusting of white spots on the surface. You can hardly see them, you have to be looking at the right angle.

The thing is the last piece I made I used kiln wash instead of thin fire and I have no dots. Do other people have trouble using thin fire and other fiber paper?

If fiber is the problem then why do people like fiber kilns so much? I always heard fiber kilns reduce dust...

[Brad Walker]

The thing is the last piece I made I used kiln wash instead of thin fire and I have no dots. Do other people have trouble using thin fire and other fiber paper?

Thin fire isn't fiber paper; they're two different products. But either can generate fumes that can cause problems with the top surface of the glass. (Other things can cause "dots" as well, so it's not necessarily the paper.)

If fiber is the problem then why do people like fiber kilns so much? I always heard fiber kilns reduce dust...

Fiber kilns are generally preferable to brick kilns because there's no brick dust falling from the roof onto the glass piece. (Yet another possible source of those "dots" you mention.) Fiber is also preferable because fiber kilns require less electricity to fire than brick kilns; that's significant as kilns get larger.

One other important consideration is that new fiber kilns have to be fired several times to burn out all the fumes, etc. from the fiber. Then they tend to fire cleaner than brick kilns.

You can also prefire fiber paper to do the same thing. But thinfire can't normally be prefired, it's a one fire product.

[Gerry669]

I understand one can reuse the Spectrum fiber paper (assuming you are very careful) i have never used it myself, but an interesting experiment, might be to "prefire" the paper then place a trial piece on the remains which have out gassed, kinda like firing a fiber kiln.

Just a thought

[Brad Walker]

I understand one can reuse the Spectrum fiber paper (assuming you are very careful) i have never used it myself, but an interesting experiment, might be to "prefire" the paper then place a trial piece on the remains which have out gassed, kinda like firing a fiber kiln.

Spectrum Papyros is not fiber paper, either. It's a shelf paper, like thinfire. It's a bit thicker, so can be fired more than once. I'm not sure why you would ever want to prefire it.

[barclayb]

Thank you for this thread. I'm considering buying a new kiln because I'm getting brick dust, which is very frustrating. Based on your input, Brad, I'll be shopping for a fiber kiln.

[Brad Walker]

Thank you for this thread. I'm considering buying a new kiln because I'm getting brick dust, which is very frustrating. Based on your input, Brad, I'll be shopping for a fiber kiln.

You don't actually need a fiber kiln, just one with a fiber lid instead of a brick one. Several manufacturers make that variant.

There are some negatives to fiber kilns, mostly centering on fiber shelves, which aren't generally as easy to use as cordierite/mullite ones. And I have heard of one particular fiber kiln that does have a "dust" problem, so you might want to solicit thoughts on a specific model before you plunk down your cash.

[jim simmons]

Also, you might want to vacuum your brick kiln before firing.
I have noticed a great improvement in the surface of my glass since I have been doing this.
The other Jim