Shinagawa refractory Mortar Cracking problem

[Tscarborough]

Re: Shinagawa refractory Mortar Cracking problem

When mortar dries, it shrinks to an amount almost equal to the amount of water added. Therefore, the more water added, the more shrinkage cracking there will be. This is not a problem with cementious mortars which have additives to address the issue, but it can be a problem with refractory cements, which have fine aggregate and do not as a rule have the shrinkage reducing agents.

The mortar should be somewhere between a 70% hydration dough and cookie dough.

[Johnny the oven man]

Re: Shinagawa refractory Mortar Cracking problem

I purchased Shinagawa refractory mortar. It's an Australasian company and the product is in New Zealand. It came in a brown bag and I was surprised it didn't have instructions but I assume you just add water. I made it up quite runny at first and as soon as it was on the brick it started showing cracks in it. I then made up different consistencies to see if it made any difference but it didn't. All of my mortar cracked straight away. It's been very frustrating for me as I find the mixing of cement and mortar is very technical and I'm a girl so never did this stuff in cooking class. The guy that served me this stuff wasn't helpful. I even mentioned before I put it in car it didn't have any instructions on package and he gave me a blank look as it I was stupid. I just assume you add water and you're suppose to know this stuff.

Sounds like too much water added, mortar should have enough "guts" to stay on the brick and actually hold it in place.

[kiwigirl]

I purchased Shinagawa refractory mortar. It's an Australasian company and the product is in New Zealand. It came in a brown bag and I was surprised it didn't have instructions but I assume you just add water. I made it up quite runny at first and as soon as it was on the brick it started showing cracks in it. I then made up different consistencies to see if it made any difference but it didn't. All of my mortar cracked straight away. It's been very frustrating for me as I find the mixing of cement and mortar is very technical and I'm a girl so never did this stuff in cooking class. The guy that served me this stuff wasn't helpful. I even mentioned before I put it in car it didn't have any instructions on package and he gave me a blank look as it I was stupid. I just assume you add water and you're suppose to know this stuff.