I just finished cooking my first few pies on a Fibrament stone. The additional mass and engineered thermal properties are phenomenal, blowing away my “Old Faithful” Pampered Chef Terra Cotta stone. At $53 delivered, it’s hard to beat. http://www.bakingstone.com/index.php
While the performance of thicker and larger stones has been discussed previously, the one thing I noticed is that many of us have eyed the big 19 inch round stone, but indicated that their oven is not big enough for the 19 and the next size down is too small. I had the same issue, as my oven was just over 18 inches deep where I would place the stone. Being a persistent Engineer who used to work in an industry where we used refractory I called the folks at Fibrament and discussed trimming the stone to fit. We discussed cutting techniques, clearances, etc. and I ended up ordering a stone. When it arrived, I drew two parallel lines on the stone, on opposite sides of the stone, to trim approximately 3/8 of an inch off opposite sides of the stone using a bench grinder. An angle grinder would do the job too, but not quite as easily. The Fibrament stone is relatively easy to grind. It’s significantly faster to grind the stone than to grind away carbon steel. I found no chipping at all during the grinding. Obviously, the thickness of the material will determine the rate of material removal from the stone, so working from two opposite sides has two benefits; you can grind the thinner edges faster and doing this provides a symmetrical finished cooking surface.
I test fit the stone a few times as I wanted to make the stone about ¼ inch smaller than the oven to allow for expansion, although the stone won’t expand nearly that much. The way I verified that the stone would fit was to leave it forward on the oven rack, then close the door, pushing the stone back with the oven door until the door was completely closed. Once the door has been opened up again, the stone can be slid back by hand until it touches the back wall of the oven. This amount is the fraction of an inch I wanted to leave for expansion.
Customer Service - My first stone was dropped hard on it’s edge by UPS, actually cutting through the edge of the box. The stone was well packed, but the package was abused. I documented the damage when I contacted UPS, as my delivery guy drops and runs. I also forwarded the pictures to the stone manufacturer for their information, but did not request a new stone from them, as I had from UPS. The Fibrament folks immediately shipped a new stone, prior to UPS contacting them. I give them Huge Kudos for great customer service.
One last item – while the directions for the Fibrament stone are clear about a staged heating the first time, I’d like to reiterate how important this is. I used to spend days drying out the refractory in large incinerators. Heated too fast, the water in the stone will turn to steam and can blow the refractory apart. If you ever get the stone really wet, which should not happed if you keep it in the oven at all times, I’d dry it out gradually again over a few hours. This drying out process will emit a wet concrete smell, so plan on some additional ventilation. I have noticed that having the stone in the oven all the time does improve the cooking most other things we prepare in the oven, although it does take longer to heat up.
The bottom line – If your oven is near 18 inches on the smaller dimension and you are comfortable working with your hands, go for it. You are essentially grinding concrete. Virtually any decent sized grinding device and a pair of safety glasses is all you need.
I anyone wants me to, I’ll post some pictures of the modified edges.