Xella

[oldshove]

I watched a couple of YouTube video's  using this product as a refractory or just drilled a couple of holes in it to make a minnie forge. Can somebody decode this information into something I can understand . [The Ytong Energy PLUS blocks are produced from Sand, Lime, Cement and Aluminium Oxide. The outher layers are made from Aerated Concrete with a density of 340 kg/m3 the the core is made from a highly insulating Autoclaved Aerated Concrete with a density of 115 kg/m3 The thermal conductivity 10 dry is (P=90%) : 0,0899 W/mK ] Thanks jmac

[oldshove]

Hers a link to a youtube video using this stuff https://youtu.be/P1Ks_Fybtfg thanks jmac

 

[timgunn1962]

What needs decoding? It seems pretty clear to me.

It's a lightweight, insulating building block. No mention of it being a refractory, as far as I can tell.

It's a (very) good insulator, but is not intended a refractory.

If you want to build a house or similar structure and maintain the inside at a different temperature to the outside, it may be a good choice subject to the myriad of other variables to be considered when building a house or similar structure.

It is not intended as a refractory.

The thermal conductivity of many materials, particularly insulating materials, is variable with temperature. When looking at the spec sheets for refractory materials, they will usually give thermal conductivity at several different mean temperatures. 

The Ytong specs I can find do not give thermal conductivity at different temperatures. The material is clearly intended as a thermally efficient building material for the construction of dwellings and industrial/commercial buildings, not as a refractory.

As a construction material for occupied buildings, the implied temperature range is perhaps -50 to +60 degC (ambient outdoor temperatures), roughly -60 to + 140 degF on the outside and somewhat less on the inside. Over this limited range, any change in thermal conductivity is likely to be small and quoting a single value for thermal conductivity seems valid.

A example of a specification sheet for a range of Insulating Fire Bricks can be found at 

http://www.morganthermalceramics.com/media/4526/firebricks-structural-range-1200-1430-data-sheet-english.pdf

Note that it includes data relating to the refractory properties of the products.

The youtube link in post #2 took me to a forge build using Refractory Ceramic Fibre board: a "real" refractory, though the one that followed it ("gas concrete propan forge...") used Ytong. 

Nothing in the video suggested to me that the Ytong was likely to make a viable refractory and there does not seem to be a follow-up video showing the Ytong forge in use.

 

 

 

 

 

 

 

[oldshove]

Thanks Tim I was a little skeptical about what I was watching [If it,s on the internet it has to be true] I tried googeling it up and I kept getting sent to that site  jmac

[Frosty]

Oldshove: Can't you find refractories where you live? Being in the Rockys I have to think there are HVAC services and suppliers reasonably close. Folk have gas and oil fired boilers to heat their homes and businesses don't they? Call around if you can't find a supplier call a service they'll tell you where they but or might let you scrounge in their cut offs. 

That's who I get my Kaowool, the local HVAC supplier and service. code won't let companies use anything but new materials in furnaces so all the trimmings get tossed in the dumpster. I haven't bought Kaowool in 20? years. I say Kaowool simply because that's the brand available to me free so it's what I use and habits are hard to break. There are many equivalent and better brands and types of ceramic refractory blanket. Use what's available.

I recommend two layers of 1" 8lb. blanket, it's easier to work with, bends with fewer and smaller wrinkles and is more commonly available than 2". Rigidize the blanket as you install it. It will be stronger so it won't sag at high temperature and encapsulates ceramic fibers so you don't have to breath them. Rigidizers also make fair adhesives to the layers hold together more easily. This last isn't a big thing but it helps a little. 

Once I have my insulating outer liner installed and drilled (I use a hole saw) for the burner ports, I plaster the liner with a high alumina, water setting hard refractory about 1/2" thick. I'm a big fan of Kast-O-Lite 30 bubble alumina water set, the bubbles are evacuated hollow spheres that reduce thermal conductivity. The added insulation not only keeps more heat IN the forge it helps reduce the absolute temperature the ceramic blanket has to survive. I get Kast-O-Lite-30 at the same HVAC supplier as Kaowool but pay for it by the bag. Wayne Coe sells and ships small quantities for reasonable though shipping to Canada adds a $ bite.

The last step is to apply a zirconium silicate kiln wash to increase the re-radiation of infra red back into the chamber and for it's chemical resistance. ITC-100 is the most commonly known brand but check with ceramic suppliers they may carry an alternative. Wayne carries two excellent alternatives.

Read the propane forge section of Iforge for much better forge builds, plans, etc. than you're likely to find on Youtube. I really don't have much to say about builder Joe's shop skills or product but he obviously never took metal shop one. 

Frosty The Lucky.

[oldshove]

Thanks Frosty for the reply . I have most of the stuff I need to build a propane forge only short a few bricks [ LOL]. I all ready have a little one I built a few years ago but I have out grown it.

I was just curious about what he was using as insulation having not seen anything about it on the forums here . The other video of using that stuff to make a one brick forge the guy really needs to look at your T burner plans. jmac