Insul Cast is a backup insulating product that can be applied under the hearth, behind the firebox, or over the dome in a fire pit or bake oven. It is ideal as an insulator for bread and pizza ovens, and should be applied with a minimum thickness of 2”. You will need 6 lbs. per square foot when applied 2” thick.
Insul Stick is also a castable restoration product but is more specifically used for parging over the firebrick in the smoke chamber or for exterior installations. It provides insulating value and strength, and can also be used to seal masonry wall penetrations. It can be cast, parged, or troweled and should be applied ¼” to ½” thick. You will need 2.5 lbs. per square foot when applied ½” thick. Insul Stick is packaged in 5 and 20 lb. pails.
Heat Cast 40 is designed for casting shapes or is used anywhere instead of firebrick. It can also be used as a hearth in a heat chamber (e.g., bake ovens, fire pits, fire boxes). You will need 20 lbs. per square foot when applied 2” thick. There is 40 lb.in each bag.
Insul Stick is usually applied as a parged product ¼” to ½” thick. It may be cast thicker. Insul Cast is typically cast 2” thick under the hearth, behind the firebox or over the oven dome. It may be cast thicker. Heat Cast 40 is typically cast 2” thick for replacement of firebrick in a firebox smoke chamber or oven. It may also be cast thicker.
A joint thickness of 1/16” to 1/8” is recommended for all Heat Stop refractory mortar products. If a thicker joint is required, we recommend the use of a dry mix - Heat Stop II or Heat Stop 50. For all of the refractory mortar products (Heat Stop Premix, Heat Stop II, Domestic Fireplace Mortar or Heat Stop 50), you will need approximately 50 lbs. of product to lay up 100 firebrick.
Heat Stop II and Heat Stop 50 can be colored just like any mortar – just follow the color manufacturer’s instructions. Heat Cast 40, Insul Stick and Insul Cast can also be colored.
The family of Heat Stop products can be found at many masonry supply yards or concrete block dealers across the USA. Heat Stop products are also available through our convenient authorized online dealer, www.MyBuildingSupplyStore.com.
Building codes require refractory products that meet ASTM C-199 (medium duty) for fireplace and chimney construction. All Heat Stop products (including the castable products Insul Stick, Insul Cast and Heat Cast 40) meet or exceed this ASTM C-199 (medium duty) requirement. Firebrick must meet the ASTM C-27 requirement, and clay flue lining must meet the ASTM C-315 and ASTM C-1283 requirements. ASTM C-105 is a discontinued specification for fireclay and should NOT be used in fireplace and chimney construction. Fireclay mixes with regular mortar do not meet current building codes.
Heat Stop II and Heat Stop 50 are the best refractory mortar products for installing clay flue lining and firebrick because they are completely non-water soluble in service after the initial set. They have an indefinite shelf life, and excellent drying characteristics no matter the humidity. These products are specified by NFPA-211 (National Fire Protection Association), in addition to meeting all local, regional and national building codes.
Heat Stop-50, the dry mix in the 50 lb. bag is the best value. A 50 lb. bag when mixed with water yields approximately 60 lbs. of mortar.
Heat Stop products are available in premix, dry mix and castable formulations. Each has its own specific application.
With regard to firebrick, clay flue lining or any of the Heat Stop refractory mortar or castable products, simply wait one day after all the masonry in the fireplace or chimney has been installed.
A fire brick, firebrick, or refractory brick is a block of refractory ceramic material used in liningfurnaces, kilns, fireboxes, and fireplaces. A refractory brick is built primarily to withstand high temperature, but will also usually have a low thermal conductivity for greater energy efficiency. Usually dense firebricks are used in applications with extreme mechanical, chemical, or thermal stresses, such as the inside of a wood-fired kiln or a furnace, which is subject to abrasion from wood, fluxing from ash or slag, and high temperatures. In other, less harsh situations, such as in an electric or natural gas firedkiln, more porous bricks, commonly known as "kiln bricks" are a better choice. They are weaker, but they are much lighter, easier to form, and insulate far better than dense bricks. In any case, firebricks should not spall, and their strength should hold up well during rapid temperature changes.ManufactureIn the making of firebrick, fireclay is fired in the kiln until it is partly vitrified, and for special purposes may also be glazed. There are two standard sizes of fire-brick; one is 9×4½×3 inches (229×114×76 mm) and the other is 9×4½×2½ inches (229×114×64 mm).[citation needed]Also available are firebrick “splits” which are half the thickness and are often used to line wood stoves and fireplace inserts. The dimensions of a split are usually 9×4½×1¼ inches (229×114×32 mm).[citation needed] Fire brick was first invented in 1822 by William Weston Young in the Neath Valley of Wales.CompositionMain article: Fire ClayFire bricks have an aluminium oxide content that can be as high as 50–80% (with correspondingly less silica).High temperature applicationsThe silica firebricks that line steel-making furnaces are used at temperatures up to 1648°C (3000°F), which would melt many other types of ceramic, and in fact part of the silica firebrick liquefies.[citation needed] High-temperature Reusable Surface Insulation (HRSI), a material with the same composition, was used in the insulating tiles of the Space Shuttle.[citation needed]Non-ferrous metallurgical processes use basic refractory bricks because the slags used in these processes readily dissolve the “acidic” silica bricks. The most common basic refractory bricks used in smelting non-ferrous metal concentrates are “chrome-magnesite” or “magnesite-chrome” bricks (depending on the relative ratios of magnesite and chromite ores used in their manufacture).Lower temperature applications[edit]A range of other materials find use as firebricks for lower temperature applications. Magnesium oxide is often used as a lining for furnaces. Silica bricks are the most common type of bricks used for the inner lining of furnaces and incinerators. As the inner lining is usually of sacrificial nature, fire bricks of higher alumina content may be employed to lengthen the duration between re-linings. Very often cracks can be seen in this sacrificial inner lining shortly after being put into operation. They revealed more expansion joints should have been put in the first place, but these now become expansion joints themselves and are of no concern as long as structural integrity is not affected.Silicon carbide, with high abrasive strength, is a popular material for hearths of incinerators and cremators. Common red clay brick are used for chimneys and wood-fired ovens.