Kiln Ventilating while firing

[Havi]

Hi everybody,
It was recommended to me to ventilate the kiln while firing with liquid enamels.
This is to let out the toxic fumes that come out of the adhesives of the enamels.
I was told to keep the lid open up to 650 degrees centigrade. I am afraid this is too high temperature.
Is it or is it not?

What is the temperature that you would recommend? Does'nt it harm the firing process???

Many thanks in advance,
and happy holidays,

Havi

[Brad Walker]

Don't know what enamels you're using, but with the enamels we use (Sunshine from Ferro) we use non-toxic binders, so there's no issue with toxic fumes. The main reason for venting (if we vent at all) is to help keep the reds from reducing and turning brown. Generally, we vent up to around 540C (1000F) when required and most of the time don't vent at all.

[Havi]

Thanks, Brad
I am using colorline enamels. After having burnt the red to black / dark brown [to my sheer shock] I asked the manufacturer what and why is this.................
I got the answer that I should keep the kiln ventilated up to 650 [1202 F] degrees.

Like I said it seems to me high, but if this is the solution - so be it.
When I want red I WANT RED, and when I want black I want black.

I am lucky the piece can tolerate this, but it is quite disappointing.

H.

[Warren Weiss]

Havi,

Venting just means the lid open only about an inch, or if you have a peep hole(s) with a ceramic plug, leave the plug(s) out to the temperature given.

Warren

[Havi]

Thanks, Warren
I would have been less bothered if it was 'only' a peep hole.
I do not have one, I'll have to have the lid open.... I think I put an glove under the lid or maybe some fiber blanket to keep the lid open.
Also I am thinking that it will have to be at a time that I can reach the kiln and pull it out at the appropriate temp. [which means not while I am not sleeping...]
Almost 11 pm here...

Thanks,

H.

[Havi]

In response to what had been said here -
1. I made another experiment, this time kept the lid open up to 604 [1119.2F] degrees. Had to get up at 1:30 am to shut the lid.
I got very dark red, it gets brighter while cooling down. But I am doubtful that it will get as bright as it was when applied - i.e. silk screened.
This is on my Jen Ken kiln, which 24" square, and quite deep [11" or so]
Only thing I can think of, is, that perhaps the lid was not open enough,? less than 1".
Could this be the reason?
I went as high as 704C [1299.2F]

On the other hand my smaller Paragon 17" dia. produced the exact same color, as it was before firing... i.e. orangey red.

This is a real enigma to me. I am planning to run another test on both kilns - to be sure how to handle this.

The trouble is that the paragon is smaller, which might be a problem - working on it, if I want to work bigger

Your responses would be deeply appreciated.
Anyway Brad, I understand that the colors you are using also distort/change red. So where am I going at all?

Havi
BTW is there any limit to the number of firings recommended, like with powders/sheet glass?

[Havi]

I want to add another thing.
It is very comfortable for me to work with wafers, powders, AND enamels. This is extremely convenient especially avoiding the problem of chemical reaction. [unless I Want it]
Also sometimes printing allows much more exact registration which is a benefit too.


H.

[Barry Kaiser]

"Only" the peep hole is not enough.Does not give good circulation of air. STill need the inch opening.

Reason for the venting is to allow the organics (which most binders (as in thinfire) and mediums are) to burn off without using up all the oxygen in then kiln. Most red pigments must oxidize to yield the rich red color.

Barry

[Havi]

Barry, thanx.

I have no peep hole anyway..................
So I guess I would need a bigger opening, bigger than 1" ???
Shall I put a kiln furniture under the lid? I worry that it will harm the bricks of the lid, perhaps I should cover the furniture with fiber blanket??


Thanx,
I want to do immediately 2 experiments on both kilns - to know exactly where I am standing, and what I can/can not do

H.
I won't fire both kilns at the same time, but I'll set them and have the second start when the first is beyond annealing