Condar uses CatGard gaskets when needed, in manufacturing high-quality CondarTM catalysts for woodstoves.
Golden flecks of mineral mica throughout the spongy CatGard material expand rapidly when heated and exposed to steam. Material maintains its expanded size, even after cooling. CatGard should never be used for other woodstove applications! Other types of gaskets are correct for doors, etc.--consult your stove dealer or chimney sweep.
Ceramic combustors, with stainless steel surrounding the catalyst, have CatGard expanding gasket inside to guarantee a continuing tight fit of ceramic honeycomb inside the steel. This may cause the stainless steel to bulge out slightly after use in your stove.
When installing a replacement combustor, always allow a visible expansion joint between catalyst and stove housing, whether your replacement is ceramic or steel.
Don't "pack" your replacement combustor into stove housing with CatGard or any other kind of exterior gasket. If installed with no visible expansion joint, your combustor is subject to premature fracturing and overheating of stove components. Unneeded gaskets make the combustors difficult to remove.
Condar's 6-inch round combustors, both steel and ceramic, are sold with an extra exterior gasket wrapped around stainless steel. This is because these round catalysts were sometimes used on early catalytic woodstoves where the receptacle is too large. Don't use the extra exterior gasket if you don't see an expansion joint during installation.
If your ceramic combustor isn't wrapped in stainless steel use the gasket provided, but don't order an extra gasket to "pack" it. Catalysts wrapped in gasket have masking tape on the gasket to hold it in position; it isn't necessary to remove tape for installation. It will safely burn off when catalyst is engaged.
If it's really necessary to use extra expanding CatGard gasket for your installation, order gasket here.
CatGard™ is a trademark of Condar Company, Columbus, North Carolina, USA.