Mortar not sticking

[jmhepworth]

I'm by no means a brick mason, but this is my experience. The mortar needs to be the consistency of peanut butter. If it's too wet, the bricks slide all over. If it's too dry, it doesn't adhere well. The Heatstop manufacturer made three recommendations to me. (1) Make sure the bricks are wet. I soak them and have had good success. If the brick is dry it sucks the moisture out of the mortar, as David pointed out. (2) Mix only what you can use in a few minutes. You cannot reconstitute refractory mortar like regular mortar by adding water to it. When it begins to set, it's not any good anymore. (3) mix with cold water. Warm water apparently starts the chemical reaction too quickly.

I make sure I press the brick into place so that mortar oozes out. For goo measure, I tap (sometimes it takes more of a smack than a tap) the brick with the butt of my trowel to set it into the mortar. I have no idea if that helps, but it seems to get the brick to stay in place a bit better.

I have 8 courses in plus the soldier course and have not had to use any support. Heatstop is very sticky.

Joe

[ThisOldGarageNJ]

I called the manufacturer of Heatstop 50, which is what I am using for my oven. I asked them if the firebricks should be soaked in water prior to mortaring. They said absolutely not!

The Heatstop manufacturer made three recommendations to me. (1) Make sure the bricks are wet. I soak them and have had good success. If the brick is dry it sucks the moisture out of the mortar, as David pointed out

I'm a little conused here, Or is the Heat Stop company a little conused ?

Any Comments

[pizza_bob]

Ugh!
I spoke to the manufacturer last week and they said the bricks should not be soaked. I'm just as confused too now!
I find it difficult to believe that there is not a professional mason on this site that knows how to use Heatstop 50 the correct way. It seems like it would be a balancing act of sorts...If you soak the brick then you can go with a slightly less water-downed Heatstop 50 mix. But a less water-downed mix then would suck moisture from the soaked brick and then have too much water in the joint. If you don't soak the brick then the water will go from mortar mix to the brick.

[ThisOldGarageNJ]

Hi Bob,
If this helps you at all, I briefly dipped my bricks in water before I laid them on heat stop that was mixed to a consistency of peanut butter. It has been three months now and i've have many fires and bakings and havent developed a single crack yet, And I have looked in the dome with a flashlight ater the oven has cooled down.

I just find it kinda strange that heat stop is giving out different information, Does anyone have a bag they can read and tell us if it says anything on the bag ?
Mark

[pizza_bob]

Originally Posted by ThisOldGarageNJ

Hi Bob,
If this helps you at all, I briefly dipped my bricks in water before I laid them on heat stop that was mixed to a consistency of peanut butter. It has been three months now and i've have many fires and bakings and havent developed a single crack yet, And I have looked in the dome with a flashlight ater the oven has cooled down.

I just find it kinda strange that heat stop is giving out different information, Does anyone have a bag they can read and tell us if it says anything on the bag ?
Mark

Mark,
Yes that is reassuring to hear you have no cracks!
I went to the manufacturer's website and found the follwoing information and attached PDF. No mention of soaking bricks though...

Heat Stop - High Temperature Resistent Refractory Mortar

[tony715]

Originally Posted by enasfournos

Hello.....
Have the same problem using fire clay,does any one know the correct ratio to mix cement and fire clay?
Have mixed 1:1 no luck, can't get it to stick to fire bricks,also tryed 2:1 no luck.if anyone knows the receipe please reply.
Thanks
gd

i used 10 sand, 6 fireclay and 2 PCL (portland cement and lime mix)

i put about and inch or beter of this mix around then entire oven as each chain was placed. i had a bucket of water with a sponge handy. after each ring i would gently sponge the inside to remove excess or to fill any voids. this alos kep tht efirebrick damp for the next ring. i woudl spread a bit of the fire caly for 1 brick, dip the brick in the bucket of water and put into place. it gives just enoug time to tap it into place but doesn't suck out the water immediately. with this mix i did the entire dome with the exception of the very top nearly form free.

hope that helps.