Ceraboard and Hardener

[daj]

Hi, I would like to make my first attempts at murrine blocks over the Christmas period, using Ceraboard dams to contain the glass.

I can't find any technical info about ceraboard or hardener in my fusing books or on the web, and would be grateful if someone could answer the following.

(1) does ceraboard need pre-firing to remove binder, if so, is 700F for a couple of hours OK?

(2) if treating ceraboard with hardener, what is the sequence of steps? (pre-fire, treat, dry, use) or (pre-fire, treat, dry, re-pre-fire, use) or (treat, dry, pre-fire, use)

Thanks in advance, and happy and safe glassing

David

[Peg]

Daj - I don't know what the right way is - but I treat, dry in the kiln, fire out the binder, use.
It can get a bit soggy and friable when wet, so maybe air-drying would be a good move.

Oh, and it stinks when prefiring out the binder.

Where are you in the UK?

[Bert Weiss]

Hi, I would like to make my first attempts at murrine blocks over the Christmas period, using Ceraboard dams to contain the glass.

I can't find any technical info about ceraboard or hardener in my fusing books or on the web, and would be grateful if someone could answer the following.

(1) does ceraboard need pre-firing to remove binder, if so, is 700F for a couple of hours OK?

(2) if treating ceraboard with hardener, what is the sequence of steps? (pre-fire, treat, dry, use) or (pre-fire, treat, dry, re-pre-fire, use) or (treat, dry, pre-fire, use)

Thanks in advance, and happy and safe glassing

David

David

I don't think that 700ºF is hot enough. I would fire it to the temp you plan to use it at. Once it turns back to white from black it is good. The job will get done faster at the hotter temps.

I have never rigidized so I can't help you there.

[Brad Walker]

I would prefire to 1400F and soak for just a few minutes. You'll know the binder is out if the color turns back to white. 700F is definitely too low, and a couple of hours is too long.

I believe that Ceraboard is a rigid product (right?), and will stand on edge. If so, then you shouldn't need to rigidize it to use as a dam material. Just cut and line with fiber paper or kiln wash well.

[Brad Walker]

I would prefire to 1400F and soak for just a few minutes. Leave the kiln open about an inch until the temperature gets above 1000F. It will stink and may smoke a little. You'll know the binder is out if the color turns back to white. 700F is definitely too low, and a couple of hours is too long.

I believe that Ceraboard is a rigid product (right?), and will stand on edge. If so, then you shouldn't need to rigidize it to use as a dam material. Just cut and line with fiber paper or kiln wash well.

[Tony Serviente]

I've used rigidizer with ceramic fiber batt, and did not pre fire before applying rigidizer. It worked well. I would actually caution against firing first and then applying, as the fiber will be much more friable and will present a greater handling(and safety) problem.

[Cheryl]

which I will only do when I need the full length of my bathtub kiln, I know that drill...

I should cut to fit the kiln, then rigidize, let dry, then fire sans glass? Does it need multiple coats of rigidizer?

[Brock]

which I will only do when I need the full length of my bathtub kiln, I know that drill...

I should cut to fit the kiln, then rigidize, let dry, then fire sans glass? Does it need multiple coats of rigidizer?

It shouldn't, but you must saturate it.

Cut to shape/size, soak in rigidizer, air dry, (or force with heat if you like)
pre-fire, finish (smooth/sand), kiln wash, fire, then . . . use. Brock

[Cheryl]

Thanks, Brock.

PS: How're you feeling after el accidente?

[daj]

Thank you to everyone who has taken the time and trouble to reply to my question - espec to Brock for his caution about needing to apply kiln wash, I had assumed that I wouldn't need to do it. Now I just need to find the time to fire up the kiln.

David