Hardy backer board - on the outside?

[BottleFed70]

I've read the posts, and it looks like the concrete backer board will work for inside an oven, but may not be the best solution.

What about on the outside? The sheet metal bill is adding up quickly and I'm thinking I might only sheet the inside and use backer board on the outside. It will definately be alot heavier, but otherwise will it be OK? I don't mind compromising on the weight a little, but If I'm putting all the effort and money into this I want to make sure it's done right.

Oven is going to be approx 2'x3'x5' with steel stud frame and 4" of insulation. I'm hoping to use it to cure ceramic coatings, so looking at 700* max temp.

What do you guys think?

[autobonifica]

sheet metal is cheap...try going to a place where they make siding or roofing for houses/buildings. i paid <$20 for a 3 1/2' x 10' piece of 26 ga steel

[hbracing]

True! Even better yet try a HVAC whole sale place and get a thinner outside skin than the inside. I can get 26-28 gauge for about $15.00 a sheet and if you figure out your price per square foot, steel is the way to go. Also that backer board can get heavy, and that may or may not be a factor. When you talk to the wholesalers, talk as you know what you want. Some don't care who they sell to. Money, CASH, talks....................

[Banditperformance]

Don't use the Hardi for the inside. Take it from someone who has $350 worth of Hardi now sitting outside the shop. I originaly did my oven inside with it, but, after an hr and a half, it was only up to 235*. I tore the hardi out, lined with tin, 1 hr and up to 400*. This is on my 7'x5'x6' oven. The Hardi just soakes up to much heat. It's like heating rocks. It holds heat for a long time, but takes along time to get up to temp, so oven heating times wil lengthen and the longer it takes to heat, the more money is wasted in power, and not being made by curing.