linning a webber with refractory material

[thezaman]

can anyone help with a formulation of perlite and some type of cement i can line my webber grill with? i want a one inch thick material that can hold some heat and be on the light side. i have built my first oven and it works well. i need a better material mix.this was a product called solid flue that is not available to me any longer

[david s]

If you use perlite in the mix then you reduce the amount of thermal mass. You also make the casting weaker. You really need to insulate the outside as well. It might work, I have successfully made a castable using 50/50 castable refractory and perlite reinforced with stainless steel needles. If you want to go a cheaper route then try the homebrew mortar recipe instead of a proprietary castable, but add some animal or human hair (which burns away) to it to create pipes that allow moisture to be removed better.

[thezaman]

this is all new to me. please explain the home brew recipe. i am trying to keep the weight down.this unit has 3/4 inch of solid flue with wire last holding it to the grill cover.i can insulate and cover the outside.

[david s]

The homebrew recipe is 3:1:1:1 sand, fireclay,lime,cement.
By adding perlite to the mix you make it more insulating so it will take longer for the heat to soak through it. You might be better off making it denser but thinner to save weight. Experiment and report back, this is good.

[shuboyje]

If you think an oven dome with no thermal mass is gonna work for you, why not just form an oven cavity out of stainless steel sheet metal. That really opens up your options for insulation. Anything from loose fill inside an enclosure to a perlcrete with very low portland content covered in some sort of render to hold it all together. I think you'll get a much better result then trying to formulate a home made insulating castable refractory that is structurally sound through many heating and cooling cycles.

[thezaman]

have any members herd of a product called solid flue?i is sed to line damaged chimneys. my friend claims it is very efficient in holding heat as well as strong.

[david s]

Originally Posted by shuboyje

If you think an oven dome with no thermal mass is gonna work for you, why not just form an oven cavity out of stainless steel sheet metal. That really opens up your options for insulation. Anything from loose fill inside an enclosure to a perlcrete with very low portland content covered in some sort of render to hold it all together. I think you'll get a much better result then trying to formulate a home made insulating castable refractory that is structurally sound through many heating and cooling cycles.

Yes, and it would enable you to lift the lid with one rather than two hands.

[shuboyje]

As for the solid flue, the product you are referencing seems to be an insulating castable refractory that is part of a proprietary system for relining chimney's in one piece. I was able to find their specs here:

Specification Data Sheet

Comparing them with the specs for Kastolite 26(found at the next link) the solid flue does have a much lower density and thermal conductivity. It is on the other hand considerably weaker them the Kastolite and the manufacturer says it is not structural. Your not looking to support a house of chimney with this stuff, just it's own weight so I would go with your gut based on your past experiences with it.
http://www.BudgetCastingSupply.com/l...Literature.pdf

If you don't mind me asking, what does this stuff run? I ask because insulating castables are notorious for being expensive, with the kastolite going for about $100 per 55# bag.

[thezaman]

solid flue cannot be purchased by anyone but a authorized dealer. i had a bag that someone gave me. I'm cost wise its in the 100.00 range. the other material if it is available to the buying public might be useful.

[shuboyje]

Kastolite 26 is just one of many commercial insulating castable refractories. I mentioned it because it is one of the more common one that seems to pop up. If you want to go that route Harbison Walker has two locations in Ohio, and could probably point you to the best product for your purpose.