Home Brew Mortar Question

[fornoa]

Hi Fellow Ovenistas',

I've just realised something about my home brew mix that could be quite a problem.
When purchasing the materials for my "home brew" mortar" (3 parts-washed sand, 1 part GP cement, 1 part -lime & 1 part Fireclay), I have just realised, "after completing the vault" of course, that I had used "Builders Clay" and not "Fireclay" in the brew.

Does anyone have any idea how much of a problem is this. Will this cause more cracking to occur than would otherwise have been the case and does it have any effect on the integrity of the vault?

Do you think I am over reacting?

Look forward to hearng your thoughts.

Cheers Fornoa.

[Gulf]

I may not be the one who should answer this but, I did a google on builders clay and found this at Boral Brick. Builders Clay

It states that it is a "fire clay" and has refractory properties. From what I have read clay can be dug straight from out of the ground, dried, pulverized, and formed into a refractory material for a WFO.

I think that you are alright, but I will yield to anyone who has direct experience with this material.

[cobblerdave]

Gudday
Dont sweat....Fireclay is unfired clay as is Brickies clay. It will proform the same function...give you a plasitic workable mortar...provide a measure of slip between the particles of the set mortar so its not to rigid. and has will not break down under heat.

Regards Dave

[fornoa]

Thanks Clobberdave and Gulf.

I checked the Boral link gulf offered and then searched further online and found another WFO site which had a the following comment "I used a mixture of fireclay (called Builders Clay down under), ".

Looks like Builders clay and Fire Clay are the same thing in Australia. I noticed at the hardware store that they also had a Brikkies Clay which was a white powder as compared to the Builders Clay which was a light terracotta colour.

I will check out the difference detween Builders Clay and Brikkies Clay and post it here soon.

Thanks for your healp guy's. I can stop worrying now.

Cheers Fornoa

[david s]

The product produced by Cement Australia called "Bricklayers clay (fireclay) is not fireclay. On contacting them they told me that it is not suitable as a refractory it is designed as a mortar additive only, who knows what's in it.When I complained about the mislabeling they said sorry but are unlikely to change it for one complaint. However because of the low temperatures we fire to I should think that any powdered clay would be sufficient.

[fornoa]

Hi DavidS,

Thanks for the input.
I will steer clear of the Cement Australia product and stick with the Boral Builders Clay.

At least they specify that it has refractory properties.

Thanks again.

Cheers Fornao.

[david s]

At 80% silica the Boral product could hardly qualify as fire clay, however I think it would still suffice at the temps we use.

[david s]

Real fireclay can be obtained from Brickpave in Brisbane. ( for Australian members)

[fornoa]

Hi Davis s,

I noted that the Boral Builders Clay has 13% Aluminium Oxide (Al2O3).
Do you know what the Aluminium Oxide content of the clay sold by Brickpave?

Could be interesting to nkow.

Cheers Fornoa

[david s]

Originally Posted by fornoa

Hi Davis s,

I noted that the Boral Builders Clay has 13% Aluminium Oxide (Al2O3).
Do you know what the Aluminium Oxide content of the clay sold by Brickpave?

Could be interesting to nkow.

Cheers Fornoa

No, sorry I don't, but you could give them a call to find out. It will be high in alumina and low in silica rather than the stuff you were going to use, which was just the opposite.The high alumina, low silica content is to avoid the silica fluxing especially in the presence of iron oxide and turning to glass-melting. nearly all Australian clays are high in iron oxide and often the % of this will also be quoted in the specs of refractory materials. But this will not happen at the temps we fire to so I can't really see a problem, I think any powdered clay should be OK. But I may be wrong