Refractory formula

[Rhett]

Anybody tried the refractory formula at ? I finally found a source for fire clay and like the look of his recipe. Going to try it unless people have had bad experiences with it.

[hpmer]

I think the Portland doesn't hold up well to the heat we produce, at least in the burn chamber and lower part of the riser.

Matt's mix seems to work quite well.

[matt walker]

Rhett, I've built with exactly that formula early on in my experimenting. It is really promising, and starts out great. Unfortunately, it breaks down fairly quickly under these temperatures. Cracking and more importantly starting to powder and just crumble apart as the bond breaks down in the Portland under the heat. So far, the mix in my core casting video is the best DIY formula I've used. Off the shelf castable refractories aren't that expensive and are the best option, but can be hard to source locally for a lot of folks.

[Rhett]

Good to know. I'll try your recipe first. I bought 250 lbs of fireclay so I should have enough for some experimenting. I'll let you know how it goes!

[Rhett]

The furnace cement I am finding on Amazon is sold by weight not by volume. Any guidelines here? For example the Rutland Dry Mix is 10 lbs for $25. Seems like a pretty good price I just don't know how far 10 lbs goes.

[mannytheseacow]

10 pounds won't go very far. If you're doing Matt's mix with fireclay 10 pounds will make a nice addition, but $25 seems like a lot to pay. My local hardware store carries big bags, 80 pounds I think, for $60. You'd probably be ok going straight clay and just adding a little of the fire cement in but for the small difference in price you could get the big bag and have less wear issues down the road.

[Rhett]

There's nothing like that around here. Are you saying you use 80 lbs for one stove or does that make several stoves? Surely 80 lbs is more than a gallon. Man I am starting to see why people have fire brick!

[mannytheseacow]

No 80# is way more than you need for one stove if you're using fireclay and an insulative material. I was just thinking that it would be cheaper in the long run to buy a big bag. I'm surprised you don't have it near you. Either way, I'm no expert. I just bought a bag to add to my next couple builds. In my home stove I used the wet mix that comes in a pail. Sorry to say, I just mixed it in without measuring anything. I've read others say they throw a couple of handfuls of the dry mix in when mixing up the rest.

[matt walker]

Yeah, I use the wet stuff. I have no experience with the dry version, I imagine it's the same, but....

Here's what I used, or the Rutland version...

http://www.amazon.com/MEECOS-1352-Furna ... ace+cement





As far as I know, it's sodium silicate mixed with high alumina clay, so when you add it to your fireclay you are giving the fireclay a boost of alumina and binding it all with the sodium silicate. You can get by with just adding sodium silicate to your fireclay/perlite for a cheaper version, but I can find this stuff at my hardware store and can handle the $15 cost of convenience. I use one quart tub for one stove, approximately. It's pretty forgiving with regards to ratios.

[matt walker]

Wow, sorry for the giant photos!