Homemade oil tank evaporator - insulation questions!

[personandy2]

hello,

My dad and I are nearing the end of the fabrication of our oil tank evaporator and are trying to determine how to best insulate the firebox.

I was planning on purchasing some of this insulating arch board from bascom's and cover it with fire brick. Our issue though is that we've been pretty thrifty with this build in mainly using extra material from around my dad and uncle's auto/heater core shop. Because of that, we cringed a bit at spending prob $100 on firebrick alone.

So my first question is, am I correct in assuming that the firebrick really is necessary to go with the insulating arch board? My assumption is that the arch board is insulating, but not fire resistant, is that correct?

On the upper level I believe the arch board, or even sand could suffice since the flames shouldn't reach up there.

Please see pics of our build so far. Grates are going in the firebox this week.

thanks!

Andy

106421064310644

[personandy2]

this is the insulating arch board

https://www.bascommaple.com/item/abin/arch_installation_supp/

[psparr]

You need to insulate to keep the tank from warping. The insulation is fireproof. You need bricks to protect the insulation only where the wood would hit the insulation. Find a construction or concrete supply store for the fire brick, they will be half the price of the maple suppliers. Hope that helps.

[Homestead Farm]

I have a similar setup. I use fire brick for the back wall of the firebox and bottom of the flat ledge only. The rest are old solid brick I scrounged. You can't use any old solid brick- many are very soft and crumbly. The ones that are hard seem to have a glaze on the outside. Mine have held up for 5 years without breaking and no steel warping, and I can lean against the side without getting burned.

Fire bricks are pretty cheap at a brickyard. Here's a tip- I found you can cut them easily with an angle grinder.

Good luck!