New twist on the 5 minute riser

I love the 5 minute riser. I have to thank whoever thought this up and they should be blessed for introducing us to something with both durability and ease of construction. Recently I've seen here and on donkey's board that folks are concerned with using the 5 minute riser in black oven applications because of the risk of the ceramic fibers breaking free into the fire path and being deposited into their food. Well I have a solution that builds on the 5MR concept that improves heat retention in the riser as well as sealing the riser to eliminate any chance of fibers escaping.

I did this with my riser and after 20 some odd firings, some of which were as hot as I could get the stove, the inner surface of my riser is still perfect. The addition is a coating of refractory material called Satanite that I purchased here: High temp tools: refractory products. It is mixed with water to a mayonnaise consistency and spread on the ceramic fiber. It is better to do it in two or three thin layers than one thick layer and one pound will do two good coats in a 5 inch ID riser 24 inches long with some to spare for touchups. I mixed it in several small batches because I couldn't estimate the amount needed to do one layer and the stuff tends to be sensitive to working time. I found it best to mix only what I could spread in 5 minutes or so, which meant four batches per layer.

The Satanite dries to a hard plaster like material that then needs to dry for at least 24 hours but I gave it 48 just to be sure. Then you heat it up a little at a time to drive out the trapped water. I used a propane torch to do this in about 8 passes. Each time it began to steam I'd stop and let it cool down, then do it over again. The last time I heated it up for about 15 minutes and no more steam was seen escaping. After that I did some light fires in the rocket stove for the next 5 firings. After that I paid it no more attention other than to marvel at the heat retention and durability under intense heat.

I hope this helps anyone needing a better environment for a black oven or just a high heat retention riser.

This seems very cool.
How hard was it to apply?
I can't help thinking that the inside of a riser is a pretty tight space.

Hi Duane;
Which ceramic blanket did you use?  
Some is highly dangerous ,with fibers coming off and sticking to our lungs.
Some , easily available Morgan Super Wool, is completely safe. (there are other brands as well) It is also expensive.

I can say that my Morgan SW riser after 1.5 years , other than feeling a little hard on the surface, is in excellent shape.
It was completely safe when I installed it and I'm sure it still is. I'm moving it from an 8" J tube to a 6" batch
I would use one in smoker anytime.

William Bronson wrote: This seems very cool.
How hard was it to apply?
I can't help thinking that the inside of a riser is a pretty tight space.

It wasn't hard at all. If you lightly mist the ceramic fiber the Satanite paste goes on about like wall plaster.

The inside of the 5" riser is a little tight but it's enough to fit my hand and the back side of a soup spoon to apply the paste to the walls. Laying the riser on its side makes it pretty easy.

thomas rubino wrote:Hi Duane;
Which ceramic blanket did you use?  
Some is highly dangerous ,with fibers coming off and sticking to our lungs.
Some , easily available Morgan Super Wool, is completely safe. (there are other brands as well) It is also expensive.

I can say that my Morgan SW riser after 1.5 years , other than feeling a little hard on the surface, is in excellent shape.
It was completely safe when I installed it and I'm sure it still is. I'm moving it from an 8" J tube to a 6" batch
I would use one in smoker anytime.

I used 1" blanket from Walmart. I wore a dust mask while cutting and placing the blanket and once the Satanite is applied there is zero chance for the fibers to go anywhere.

The ceramic fiber blanket itself is more than durable enough by itself in a riser, but for those that don't want the fibers going airborne for whatever reason this is a solution that improves the heat staying in the flame path better than the blanket by itself. It's just another refinement that some may choose to adopt if they like the idea.