Refractory Mortar Poll Tools, Tips and Techniques Discuss Refractory Mortar Poll in the Pizza Oven Design and Installation forums; Thanks to everyone who is contributing to this poll and discussion. For those of us starting out (well for me, ...

[kebwi]

Thanks to everyone who is contributing to this poll and discussion. For those of us starting out (well for me, I can't speak for anyone else) these expositions are quite informative.

[Frances]

I used a mixture of refactory clay and refactory sand - no cement component at all. The whys and wherefores are in this thread:

http://www.fornobravo.com/forum/f8/h...clay-2783.html (Heat-dry mortar made of refactory clay and refactory sand (and nothing else))

I think some other forum members have used this kind of mortar since (dvonk for one).... and it still seems to be working fine after nearly two years of use. Of course the intresting question would be what its like after 20 years or 100.

I'll be sure to let you know when we get there

[dmun]

@dmun, I have access to HeatStop 50 here. It's $70-$80 a bag! I was planning on using it except that I started wondering about other options.
Let me ask you this, I'm making a 36" oven. Can I do it with one bag? (Let's see, the directions suggest 130-180 lbs. Is that dry weight, as in 3-4 bags of HeatStop?)

Heat-stop is expensive, and it's not immune to cracking. I used less than one bag for my dome, but my dome is thin, and cut-to-fit, an approach I don't necessarily recommend. I spent more in diamond blades than I did on heat-stop.

[skemcis]

I used a product called Super 3000 Dry mix. I blended it 1:1 with sharp sand from our creek. It worked out well, there's a few cracks but that's to be expected, and I can't complain seeing as I have not woken up to a pile of rubble where the oven used to be. This oven has produced over 500 bread loafs and countless pizzas in the last 2 1/2 months. I am very happy....

Ian

[ThisOldGarageNJ]

my heat stop was $ 67.00 a bag with tax. I used about 3 1/2 bags. As i said before in other posts, Much of my use was loss and dropping due to inexperience, Only mix a little at a time,, Be as careful as you can,, keep your joints as tight as you can,, i have a 42" interior dome, Im sure i could have done it in 3 bags, maybe 2 if i was really carefull... Now I know better for when I build my next oven (haha)
Mark

[berryst]

I used:

10 sand
6 fire clay
2 portland cement
2 lime

I have been using the oven for over a year. I like using it in winter here during the long and rainy seattle/north west winter.
I have no spalling or cracking of any kind. Seems like a lot of you like the spendy heat stop . Seems like its not a bad Idea but my mix works just fine and its a lot lot cheaper
berryst

[splatgirl]

I used Sairset premixed, air drying. I'm not sure i'd recommend it, but it sure was a time/waste saver not having to mix mortar every time and it was very easy to work with otherwise as well. I did get some cracks, but no more so than what I would have expected with any other product and no worse than what I've seen posted here. My joints are not very tight. I used 3 pails for my 36" ID oven at a cost of $52 for 55 lbs.

What I think is questionable about it that I didn't consider beforehand is that it needs to be fired to cure which is presumably not a problem for the dome, but...I have no idea what the curing temp is, and I'm fairly certain the front of my arch and vent would never get up to that temperature anyway, so basically I'm assuming those parts are never going to "cure". I didn't think about this until after the fact. I'm not sure it's an issue, but talk to me in five or ten years and we'll see. Right now, I can't say I'd have chosen differently even if I had considered the above, because not having to mix and adhere to the timing of cementitious mortar was a HUGE benefit, IMO.

[ThisOldGarageNJ]

Seems like a lot of you like the spendy heat stop . Seems like its not a bad Idea but my mix works just fine and its a lot lot cheaper
berryst

Hi Berryst... It really wasnt a matter of liking the heat stop 50,It did work well but, It was readily available and a known used product, Being an amateur mason I prefer to remove as many variables as possible.... and sourcing fireclay wasnt working out too well, There were no shipping charges on the heat stop either as they had it where I got my fire brick

[jmhepworth]

Originally Posted by ThisOldGarageNJ

Hi Berryst... It really wasnt a matter of liking the heat stop 50,It did work well but, It was readily available and a known used product, Being an amateur mason I prefer to remove as many variables as possible.

Exactly. That's why I used Heat Stop. It was rather expensive, but it worked.

Joe

[Lars]

My mix, very similar to BerryST... 3:2:1:1/2 ( Fine sand, Fire clay, Portland, Lime)

Oh what a wonderful mix. The Portland holds it together so tight while under construction, then burns out when you cure the oven (AFTER you have a waterproof dome, right?)

When you fire it up to full temp, the fireclay becomes brittle and non-absorbent. Any gaps in there filled with fireclay mortar simply become like more firebrick over the years.

A joy to work with, not exorbitantly priced, classic fireplace mortar.

I mixed it up in the buckets I got from a kiln supply place here ( that had a few inches of high test ==water soluble== heat resistant mortar) hold the fancy expensive stuff that NEVER would have worked on this oven, out doors...

Just scoop 6 sands, 4 fireclays, 2 portlands, and 1 lime, pour it into a hod and mix for maybe 5 minutes, pour it back into the big plastic bucket with the sealing lid, and then mix up enough for a 1/2 chain at a time. Then next day your work is stuck down like a rock.