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Firebrick and Insulation FAQ

October 15, 2018

General Overview

Evaporators need to be insulated and bricked before first use. This is done for many reasons. It protects the arch from extreme heat and prevents the steel from flexing. The insulation protects you, the operator, from the heat. It also helps direct the heat exactly where you want it: under your pans to heat up that sap.

Ceramic Insulation Blanket is not your average blanket. It’s amazing stuff. You could aim a jet burner at it all day and it would never burn. Its responsibility is to do all your insulating and it will never disappoint. In order to protect the ceramic blanket, we line the firebox with firebrick. That way, we won’t scuff or snag the ceramic blanket whenever we throw in firewood.

Remember, Firebrick itself is NOT the best insulator. That’s why we use it in home wood stoves, because it allows the heat to pass through. In a maple syrup evaporator, the Firebrick’s primary function is to protect the ceramic blanket insulation, and not to act as an insulator. Using too much firebrick could contribute to sluggish startup and protracted shutdown. That is why we only use Firebrick in areas that are absolutely necessary within the arch.

Frequently Asked Questions

Question Answer
Shouldn’t I lay bricks throughout the entire interior of the evaporator?The ONLY reason for firebrick is to protect the ceramic insulation from the firewood. Gas/Oil Evaporators do not require brick.
Should the belly riser be placed above or below the insulation?Belly Risers (applicable to Corsair evaporators) are positioned under the insulation to be protected from the extreme heat of your fire. A belly riser’s purpose is to optimize the geometry within the Corsair arch and force heat into/against a Raised Flue Pan/Flat Pan. (By removing the Belly Riser, the Corsair arch geometry is optimized for Hybrid Pans or Drop Flue Pans.)
What other insulation is needed besides the Ceramic Blanket?Ceramic Insulation Blanket is the best insulator there is for the high temps inside an evaporator.
How hot do the un-bricked sides along the rear of the arch get?While there may indeed be insulated areas of some of our arches where you could place your hand against the outside for a couple seconds, the best rule of thumb is to always avoid touching an arch while it’s in use/hot. Some areas — such as the area by the smoke exhaust — will become extremely hot. Keep spectators and pets several feet away from the back of the evaporator.
No bricks or insulation needed under the grates?Bricking and insulating underneath the grates is not necessary. However, if you have leftover Ceramic Blanket, the floor under the grates is a good place to lay the leftover material. That would catch any coals or ash that could potentially fall through the grates.
Can I run my evaporator on top of a combustible floor?Cement board, tile, or another fireproof material should always be under the arch.

Product Support

Related Articles

Understanding Stack Temperature

How To Get The Most Out Of Your Firewood

Flat Pan Vs Divided Pan


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keith bredow

February 13, 2020

I purchased a dauntless 10 to 55 taps unit. information on the web site said the fire brick needed could be purchased at a local hardware store. I wasn’t able to find the 1″ x 4-1/2″ x 9″ recommended on the site. 1 1/4″ x 4-1/2″ x 9″ are common, will they work? also do they need to be set in high temp mortar?

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February 13, 2020

The size you specified will work perfectly. No, you do not need mortar because the Dauntless arch was designed with angled walls. This allows the bricks to lean back and stay in place without mortar.

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Roger Nordstrom

October 10, 2020

I just built a sugar shack for my 2’x4′ Corsair arch. I understand I should place the arch on cement board. How far from the walls should the arch be placed?


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October 11, 2020

Hi Roger. Congrats on your new sugar shack. Please leave a minimum space of at least 18″ between your stack and all combustibles.

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January 16, 2021


I am building an evaporator from an old oil tank. Now I am looking for some fire bricks should I use – 6.5 x 9 x 2.5 inches, 4.5 x 9 x 2.5 inches or would 4.5 x 1.25 x 9 inches be good enough? Also where in Ontario Canada can I purchase the Ceramic Insulation Blanket you mention? Would these bricks have to cemented in with high heat cement?

Thank you in advance for your advice.