Fire brick Mortar Mix question?

[EricU]

I have poured my insulating slab and am ready to start the 42" dome construction and I have the following questions regarding the fire brick mortar mix design:

Pics of build (Started in Napa, WFO dome & slab questions)

Per the Forno Bravo oven building instructions (Appendix 6. High Heat Mortar) and from the forum the Fire Brick Mortar mix is;

1 part Portland Cement
3 parts Sand
1 part Lime
1 part Fireclay


I am using a product by HC Muddox labled “Mortar Clay” and the bag has the following mix instructions;

1 part Mortar Clay
2 parts Portland Cement
6 parts Sand
With NO additional Lime.


Should I use the FB mix instructions with the HC Muddox Mortar Clay?

Or should I follow the mix instructions on the bag?


Thanks for any help, Eric

[fxpose]

I used the Forno Bravo ratio with the HC Muddox Mortar Clay.

George

[EricU]

Originally Posted by fxpose

I used the Forno Bravo ratio with the HC Muddox Mortar Clay.

George

So, just to be clear, you used (hopefully with no problems) the following;

1 part Portland Cement
3 parts Sand
1 part Lime
1 part Fireclay with the Fireclay being HC Muddox product labled “Mortar Clay” right out of the bag?


Thanks Eric.

[fxpose]

Originally Posted by EricU

So, just to be clear, you used (hopefully with no problems) the following;

1 part Portland Cement
3 parts Sand
1 part Lime
1 part Fireclay with the Fireclay being HC Muddox product labled “Mortar Clay” right out of the bag?


Thanks Eric.

Yes, that's exactly what I used and ignored the instructions printed on the mortar clay bag.

[fmottahe]

Are you suggesting that Muddox "Mortar Clay" mentioned in this thread can be used in place of FB high temp water resistant mortar? There is a very large price difference.

Regards,

[fmottahe]

Are we saying using Muddox Clay Mortar mixed properly is equivalent to using FB high temp, water proof mortar?

Thanks,

[GianniFocaccia]

Eric and fmottahe,

If you haven't had the pleasure of reading thorugh this high-heat mortar primer, I invite you to do so since it answers the questions you will most likely ask next, plus gives an idea of what other builders have done.

http://http://www.fornobravo.com/for...rimer-914.html

Personally, I couldn't see paying $90 for a $50lb bag of HeatStop 50 when I could "roll my own" as Les calls it. Like many other builders, I picked up 50lb bags of HC Muddox Mortar Clay, hydrated lime and Portland cement. I also had 400lbs #12 fine silica sand given to me. Total investment: about $30.

I started with the traditional FB 1-3-1-1 ratio but started to ease back on the portland just a tad since it was reported this is what burns out at temerature over time. I didn't have the guts to go all fireclay and sand like Francis, but I figure my oven will outlast me. I haven't noticed a difference in mortar integrity. This mixture is a joy to use and it's ease of application is one of the primary reasons I'm milking this build and spending every weekend minute I have working out in the backyard manicuring bricks and drinking beer.

[AnthonyW]

Hello - I am planning to build my first oven this spring. I have been gathering supplies and refining plans since October. I purchased a couple bags of FireRock Mortar Adhesive from a block company. Is anyone familiar with this product? Will it work as mortar for the oven?

Thank you!
Anthony

[whowaaa]

use fire clay 1 to 2 cement and 3 sand...you need NO LIME it takes the place of lime...