Forge supplies

[Creature]

I'm having a hard time finding any of the high temp refractory products.  All kinds of the USA but would much rather find it in Canada. Any Canucks point me in the right direction. 

[swedefiddle]

Good Morning,

I can't remember Ontario Artist Blacksmith Association members in your area. Check out their web-site ontarioblacksmiths.ca

John Newman frequents this forum, he is in Hamilton, Newman Forge and Pattern.

Hi-temp bricks are very fragile, they will crack and break with the slightest bump. I have found that the regular Fire-Bricks take longer to heat up and refract, but they don't break as easy or as often. Sometimes it is mind over matter, Does it really Matter?

Neil

[Mikey98118]

You should be able to find Kast-O-lite 30 (which is rated at 3000 F); that should both have more than a high enough temperature rating for any forge. What you want to do is to add a high-emissive finish coating over the refractory to raise its heat reflection. 

[Creature]

There is a pottery club in town is any of the kiln supplies good for a Forge.  

What temp does the brick need to be rated to? 

[Mikey98118]

I wouldn't use brick; not even insulating firebrick. High alumina kiln shelves perform well at higher temperatures than most hard firebrick, while resisting heat transfer seven times more than hard firebrick, and are much thinner, so that more insulation can be employed beneath them. Thus it can truthfully be stated that when these two advantages are added together, 34" high alumina kiln shelving will outperform hard firebrick as a hot-face, and insulated firebrick for slowing down heat transfer. High alumina kiln shelving is available at pottery shops for modest prices; it can be separated by marking all the way around, and then lightly scouring with a cutoff disk in a small angle grinder, and then gradually deepening the scores all the way around the shelf, until it cracks apart at the score lines.

[Mikey98118]

Also, kiln shelf can be supported on 1/8" oversize slits in front and rear shell faces.

The brick, poured castable refractory, or high alumina kiln shelf is the part you burner flame is usually meant to impinge; therefor the forge floor is the only area which must be highly temperature resistant; at least to begin with. Most people use rigidized ceramic fiber, with a kiln wash finish coat everywhere else; all these products are available at the local pottery supply store.

[Buzzkill]

For kiln shelf I went to a pottery store about 10 miles from where I live.  I asked if they had any broken pieces I could buy.  I walked out with 3 decent size chunks for 10 dollars and easily cut the shapes I wanted using an angle grinder with a masonry cutoff wheel.  A metal cutoff wheel would probably work well too.

[Creature]

Is this vesuvius super 3000 a good castable? 

[Mikey98118]

They do; masonry discs just last longer in ceramics, because they don't heat up as much in very hard materials. Peaple should remember to wear a two string dust mask, if they don't have a respirator.

I'm assuming that you will be using a homemade kiln wash over over rigidized ceramic fiber, instead of the Kast-O-lite 30 refractory. I've not made up my own mind yet, as to which path is "best"; it is probably a matter of preference as to whether resistance to heat, or superior blocking of heat transfer is most important to the building. Bouncing ideas back and forth with Frosty has shown me that my own building preferences are not necessarily clear winners over his (sometimes inconvenient) common sense

About rigidizer: A few years ago most rigidizer was made with fumed silica; only one product was available, which  wasn't; it was a very thin ceramic slurry. Fumed silica dissolves and stays suspended in water (being colloidal). Use food coloring to suit; this allows you to easily distinguish how deeply your rigidizer is penetrating the ceramic fiber blanket or board, and completely burns out during heat curing. Force dry the soaked fiber with the wife's hair dryer, before applying low flame, intermittently, until no  more steam leaves the hardened fiber, and all coloring is gone. then turn the flame up on full for a few minutes to make sure the silica melts, locking the individual fibers in position. Most commercial versions of rigidizer are mixed thirty to forty percent by volume in water, but any amount that leaves the finished product thin enough to squirt through a spritzer is fine. If you use too little fumed silica, you will be able to tell that after the ceramic fiber is flame cured (melted in position), and can add more fumed silica to your mixture; then repeat the process. If you add too much fumed silica, your rigidizer won't pass through the spritzer's valve; jut add more water. It is natural to wonder how much rigidizer will degrade  a ceramic fiber product's ability to insulate. The answer is barely at all.

At present, eBay has the best deals on fumed silica. Unless you live in an area with very hard water (high mineral content), using distilled water is probably a waste of money. 

[Mikey98118]

My preferred method for suspending a high alumina kiln shelf, is by cutting an 1/8" oversize slot at either end of a cylinder for the kiln shelf to protrude through. With sufficient ceramic fiber used as a pillow under it, the unheated fiber pillow, will act as a spring, holding the kiln shelf in place; even after the ceramic fiber "takes a set" this pillow will help hold the shelf in place. For those who like a hinged opening on one end of their forge, the shelf can be cut just long enough to fit snug  within the shell, and wide enough for the circular wall to keep it from being pushed too low in the forge;