Finding Materials?

[sancha]

hello, for the first layer of the dome what is the best material? Stucco?

[david s]

I have been doing a bunch of reading and have decided to use the homebrew mix (3:1:1:1 sand, portland, lime, fireclay) to make the refractory layer in a cast oven. I cannot find hydrated lime locally. would if be safe to use this product as the portland and lime for this recipe?

https://www.homedepot.com/p/Quikrete-70-lb-Type-N-Masonry-Cement-112570/100318484

Thanks in advance.

John

No, those premixed products usually contain lime in the form of crushed limestone (not suitable). If you can’t get hydrated lime you may be able to find hydraulic lime which is another suitable alternative.

[david s]

Yes there is a different mix designed for the purpose. It’s called castable refractory and relies on calcium aluminate cement rather than Portland. It is expensive. Using the home brew as a castable does work, probably not quite as good as the proprietary castable refractory, but is really cheap.

[mazzazza]

The homebrew mix is really more for sticking firebricks together with though. I don't think the consistency would be right for using in place of firebricks. I'm sure there's a different mix for refractory concrete but I don't know what that is.

[mazzazza]

If it's 50:50 Portland cement and lime, which it looks like it is, then yeah it'll be fine. You'll just want to do 3:2:1 Sand:mortar mix:fireclay.

[Johno4]

I have been doing a bunch of reading and have decided to use the homebrew mix (3:1:1:1 sand, portland, lime, fireclay) to make the refractory layer in a cast oven. I cannot find hydrated lime locally. would if be safe to use this product as the portland and lime for this recipe?

https://www.homedepot.com/p/Quikrete-70-lb-Type-N-Masonry-Cement-112570/100318484

Thanks in advance.

John