Has anybody used DuraBoard as mold?

[Lia Howe]

I am making a very simple wine bottle slumping mold but I need to make the mold last. FiberBoard works great but it does break down over time, every bottle takes a little of the mold. I found this stuff in that pile of supplies we all have hidden in a back corner. I can figure out the cutting by ruining a few of my husbands power tools ( SH! don't tell him) Would I need to kiln wash the mold to get a smooth finish? Can you kiln wash this stuff? any help would be great. Thanks Lia

[Bert Weiss]

Lia

I routinely use duraboard as both a shelf and for mold components. The best approach for me is to simply dust it with alumina hydrate. You can kiklnwash it, but kilnwash needs to be refreshed after firing hot, and there is no way to scrape it off, when it chips or gets funky. You could use Primo kilnwash, which utilizes an organic binder. You could also use colloidal alumina which is more expensive than powdered alumina.

It might be possible to make a putty with colloidal alumina and powdered fibers, and use it to fill in gaps in the mold surface. Moldmix 6 is made this way. You can also use colloidal silica for this, but then you really need kilnwash or it will stick.

[Lia Howe]

How do you cut it? My husband bought me a RotoZip to create the interior shape. I think that it will work the best. Any cautionary tales to help me not replay old mistakes? I am going to cut outside so the dust won't be as bad. Any advise will help me.Lia

[Marian]

Dura board and fiber board are the same thing, aren't they? Real soft- and like foam. Shape them with a spoon?

[Bert Weiss]

Dura board and fiber board are the same thing, aren't they? Real soft- and like foam. Shape them with a spoon?

Hi Marian. There are different grades of fiber board. It is graded on density (weight) low medium and high LD MD and HD.

I cut all of them with a razor knife. I like those segmented long blades.

[Lia Howe]

The fibre board I have is very soft ,yes you can cut it with a knife but it gives a little to the glass everytime you fire it.
The Duraboard I have is very firm. I am hoping that it will stand up better and a little longer than the fibre board.

[rosanna gusler]

beware the rotozip. keep whichever hand that is not holding the machile well away. if you decide to use it to cut moulding or anything stick like in two, clamp the thing to be cut into a vise. do not hold it in your hand. i grabbed the rotozip to trim a piece of shoe moulding. held the molding in my left hand, the tool in my right. the rotozip tourqued left anong the wood and ate up my left thumb. not pretty. even dumber? about 6 months later, i did it again thinking that i just needed to hold the little bast..er rotozip more firmly. i hate my rotozip. rosanna

[Mike Jordan]

Not everyone has them, but I've used my scroll saw to cut 1/2 to 1" thick fiber board. It works great with a regular downward facing fine tooth blade or one of the very thin round blades that lets you go in any direction (like the blade on a ring saw but much thinner). I wear a mask of course and keep the dust down by putting wet paper towels all around the saw. My scroll saw has a 16" throat so I can cut a shape out of any size fiberboard up the 21" size of my shelf.

Mike

[Bert Weiss]

The fibre board I have is very soft ,yes you can cut it with a knife but it gives a little to the glass everytime you fire it.
The Duraboard I have is very firm. I am hoping that it will stand up better and a little longer than the fibre board.

Duraboard is the Unifrax brand name, and it does come in all three grades. I have used Chinese boards. They too come in different densities. In general the Chinese boards I have cut, had hard and soft spots throughout the boards. I have bought Chinses LD boards that were so poorly made that the fibers were flapping in the wind. (these cost 1/3 Unifrax prices, but I got less than what I paid for.)

In my experience, Unifrax is the top of the line, followed in both price and quality by Thermal Ceramics. The Chinese are hit or miss. All that said, I still like the Chinese HD boards from intersource for 1/2 price of Unifrax.

[S.TImmerman]

Where can I buy duraBoard? Or fiberboard? Which is better? Thanks!
St

[Lia Howe]

I can buy both from Pottery Supply House in Oakville, Ontario. If this doesn't help, I am sure any pottery supply or Kiln building company will carry these both. Fibreboard is great, easy to cut, makes me itchy just thinking about it. Duraboard, well I don't know yet as I have not used it yet. I have high hopes though.Lia