Go Back   Forno Bravo Forum: The Wood-Fired Oven Community > Pizza Oven Design and Installation > Getting Started

Like Tree3Likes

Reply
 
LinkBack Thread Tools Display Modes
  #81  
Old 01-27-2014, 06:40 PM
Apprentice
 
Join Date: Dec 2013
Location: Wisconsin
Posts: 135
Default Re: High Heat Mortar Primer

Quote:
Originally Posted by brickie in oz View Post
I have only ever used the pre mixed junk once, it was for a small patch up job and I didnt want to go to all the trouble of sourcing and mixing mortar.

In all my years of bricklaying maybe 30 I lost count, but more that 25, I have never struggled with mortar until I used pre mix.

What an abomination on man kind.
Brickie, pre mixed mortar is now the newest thing for masonry construction. Being a mason for 32 yrs. I have learned to live with it. It doesn't have anywhere the workable aspects of a sand pile, a skid each of lime and portland cement. For standard mortar for brickwork you could not beat 32 shovels of sand and a bag each of lime and cement. Hence type "n". Boy could a guy work with that mortar. Today's mortar that comes out of silos acts like grout, i.e. has not plasticity. Mortars have gotten stronger so now we need control joints in brick veneers ever 25 feet and at every corner. Old buildings in my area never had CJS because the mortar was meant to give a little bit. Just my 2 cents about today's mortars. So as far as making my own home brew for less money or buying something in a pail or bag that is premixed and costs a lot more you can figure which way I am going. You bet I will mix my own and make it so I can work with it. Just thought I would give some thought.
Reply With Quote
  #82  
Old 11-08-2014, 03:07 PM
Serf
 
Join Date: Nov 2014
Location: WA, USA
Posts: 1
Default Re: High Heat Mortar Primer

On "oldie but goodie" topic.

1) I'm curious if the order of mixing the ingredients matters, and if so why? (I just want to learn a little more about the chemistry or physics or practicalities of it.)

I would have thought to mix the finest-grain ingredients together first (Portland cement, fireclay, and lime), and only after they are mixed then mix in sand. Sort of like sieving together the flour and baking-powder first, in a cake mix. But the list of ingredients (1:3:1:1, as in 1 part Portland cement, 3 parts sand, 1 part lime, 1 part fire clay) and what I've read elsewhere suggests mixing the sand and cement together first, and then adding the lime, and the fireclay last.

2) Sand: how "fine" is fine-grain? Let's talk mesh (size of grains). Is #50 fine enough? Is #80 better, or is it too fine? #120? The latter seems like powder, to me. It is available where I live down to #400 mesh, which is a very fine dust like kaolin powder; even finer particles are available for specialized purposes. ("Mesh" refers to the size of the opening the grains will fit through, when sieving.)

3) Also, how much water to add? This seems to be left out of the recipe mixes. Perhaps the various videos or pics tell this better than words, to get the right consistency. I used to think that the less water the better (within reason) for strength, as this is what I learned using Quikrete in driveways (non-refractory application, of course!) -- too much water weakens it. But some experimentation quickly revealed that too little water is also a problem in making refractory mortar, the mix never really adheres to itself, doesn't hydrate/cure enough or right, and is very weak and crumbly. (Even if one could form a ball that held together after pressing it in your hands, that wasn't wet enough -- it needed more water.) Like Goldilocks and porridge, I guess it has to be "just right": well-mixed, not to dry and not to wet.

If the order of mixing isn't important, would it help to mix the cement/lime/fireclay first, then (separately) add water to the sand and then mix the wet sand with the dry ingredients, to help spread the moisture around?

Just brainstorming, to learn from the pros on here. :-) Many thanks to those who really know, for sharing your insights here!)
Reply With Quote
  #83  
Old 04-27-2015, 06:35 AM
Serf
 
Join Date: Mar 2015
Location: Milton Keynes/Uk
Posts: 14
Default Re: High Heat Mortar Primer

Hi guys. I have a query on what people have found best to work with.
I have found a ready mixed high temp cement from a wood burning oven specialist. He also sells dry cement to just be mixed with water. Both rated to 1600.
However it says that it should be applied between 2-5mm.
What have people found best to use?
The lime, fireclay, cement and sand mix or these specialist high temp cements?
I'm in really split minds and am very unsure which way to go?
I'm building my dome with old red clay bricks.
Interested to hear people's reaponses and how you guys have done it?
Reply With Quote
  #84  
Old 04-27-2015, 07:34 AM
Tscarborough's Avatar
Il Pizzaiolo
 
Join Date: Oct 2009
Location: Ausitn
Posts: 3,240
Default Re: High Heat Mortar Primer

This question has been answered dozens of times, several in this thread. Search around a bit.
Reply With Quote
  #85  
Old 04-28-2015, 06:38 PM
Apprentice
 
Join Date: Dec 2013
Location: Wisconsin
Posts: 135
Default Re: High Heat Mortar Primer

Quote:
Originally Posted by FrankHawkins View Post
Hi guys. I have a query on what people have found best to work with.
I have found a ready mixed high temp cement from a wood burning oven specialist. He also sells dry cement to just be mixed with water. Both rated to 1600.
However it says that it should be applied between 2-5mm.
What have people found best to use?
The lime, fireclay, cement and sand mix or these specialist high temp cements?
I'm in really split minds and am very unsure which way to go?
I'm building my dome with old red clay bricks.
Interested to hear people's reaponses and how you guys have done it?
Don't waste your money on high temp mortar if you are using red clay brick. You should be using medium grade firebrick, not a clay brick. You can but for an oven that lasts use firebrick. Do some research on the proper materials to use.
Reply With Quote
  #86  
Old 04-28-2015, 07:13 PM
GianniFocaccia's Avatar
Il Pizzaiolo
 
Join Date: Jun 2009
Location: Disneyland, CA
Posts: 1,624
Default Re: High Heat Mortar Primer

Quote:
Don't waste your money on high temp mortar
+1

Homebrew all the way.
Reply With Quote
  #87  
Old 04-28-2015, 07:44 PM
Serf
 
Join Date: Mar 2015
Location: Australia
Posts: 17
Default Re: High Heat Mortar Primer

Quote:
Originally Posted by Campmaki View Post
for an oven that lasts use firebrick.
Campmaki, What do you mean for an oven that lasts? What time frame are you referring?
Reply With Quote
  #88  
Old 04-29-2015, 05:15 AM
Serf
 
Join Date: Mar 2015
Location: Milton Keynes/Uk
Posts: 14
Default Re: High Heat Mortar Primer

Also interested to hear what time scale your referring to. I can't afford firebricks so had to use the old red clays that I have. I've read in many places that they are a fine alternative to fire bricks. Seems to be mixed views about them. The cost has mounted up so much more than I thoughf when I started this project I have no option other the the old red clays so really hoping that they hold up to the job! Lol
Reply With Quote
  #89  
Old 04-29-2015, 08:36 PM
cobblerdave's Avatar
Il Pizzaiolo
 
Join Date: Jan 2010
Location: brisbane australia
Posts: 2,598
Default Re: High Heat Mortar Primer

G'day
If at all possible use firebrick for the hearth, they'll handle the heat better. If not commons ar'nt twice there width to there length to allow for a mortar gape. Don't use herringbone pattern the gapes will be too big. Lay the floor at 45 degrees to the entrance and you'll be right
Regards dave
__________________
Measure twice
Cut once
Fit in position with largest hammer

My Build

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

My Door

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -7. The time now is 06:09 PM.

Powered by vBulletin® Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
2006/10 Forno Bravo, LLC