QUIKRETE Refractory Mortar Mix

[mpholland]

Has anyone modified the regular Quikrete Mortar Mix by adding fireclay to make an acceptable refractory mortar mix? If so, how much fireclay to add per 60 pound bag?

[Dutchoven]

Re: QUIKRETE Refractory Mortar Mix

It would be a difficult task to do so...the mix you refer to is a type N mix which would mean equal parts of cement and lime to approximately 6 parts sharp sand...however I think there is an acceptable range for sand content that might increase that amount to over the 6 parts that is customary...very hard to figure out how much fireclay to add and one probably could not tell by sight or feel unless they had been working with such products for a long, long time...a place that carries fireclay should carry type N mortar which would be premixed hydrated lime and cement in a 1/1 ratio...you would then be able to add the fireclay and sand...
Hope this helps!
Dutch

[woodhead]

Re: QUIKRETE Refractory Mortar Mix

MP

by no means am i a mason or an engineer, but follow the 1:3:1:1 refractory mortar mix recipe....type s lime, masons sand, portland cement, fireclay...works like a champ!!

Woodhead

[rlb444]

Re: QUIKRETE Refractory Mortar Mix

Yes type N mortar with fireclay works great and would probably work best. 5 parts N and one part fireclay is the correct formula for fire mortar 1 1 3 1 .Type S has twice as much lime in it for a 1 part portland 2 parts lime and 3 sand. Adding one part fire clay would give you a 1 2 3 1 formula. Type S is rated for underground wet areas. For a 60 lb bag of mortar I think you would need about 12 lbs of fireclay.

[cynon767]

Re: QUIKRETE Refractory Mortar Mix

Yes type N mortar with fireclay works great and would probably work best. 5 parts N and one part fireclay is the correct formula for fire mortar 1 1 3 1 .Type S has twice as much lime in it for a 1 part portland 2 parts lime and 3 sand. Adding one part fire clay would give you a 1 2 3 1 formula. Type S is rated for underground wet areas. For a 60 lb bag of mortar I think you would need about 12 lbs of fireclay.

So what would be the best way, hypothetically speaking, of mixing up a suitable blend using type S mix?
-Add one part portland cement, one part fireclay, 5 parts type S?
-Or add 1 part cement, 2 parts fireclay, 1 part type S mix, 3 parts sand?

-Or, does the type S mix already contain enough sand to cover this?

...Or am I just way off base here with a neophyte brickie quiestion? I will probably have some extra type S from another concurrent project, is why I ask.

[Dutchoven]

Re: QUIKRETE Refractory Mortar Mix

I think rlb has it backwards...there is less portland cement in type N than type S...type N for general building consists of 1 part portland 1 part lime and 6 parts sand whereas type S consists of 2 parts portland 1 part lime and 9 parts sand...if you have the the type S mortar(without the sand) as opposed to the mortar mix(already has the sand in it and you just have to add water) you might be able to mix an extra half a cubic foot of hydrated lime with one cubic foot of type S mortar and the 3 cu-feet of sand and 1 cu of fireclay to be pretty close to the 1-3-1-1 recipe...if it is the mix it will be much tougher to do...IMHO
Best
Dutch

[cynon767]

Re: QUIKRETE Refractory Mortar Mix

Thanks for the feedback... That makes more sense. It is the mix, not just the mortar. I will probably go ahead and buy fresh materials and mix from scratch. I'm sure I will find a use for the mix I have, what with the variety of masonry projects I have going on simultaneously.

[Dutchoven]

Re: QUIKRETE Refractory Mortar Mix

Jamie
Another word to the wise...when you get the sand for the oven mortar(refractory) try to get the sharpest or finest sand possible...it will make for a nice workable and smooth mortar for those tight joints...if you are bricking the enclosure or for the outer arch it is not such a big deal
Best
Dutch

[cynon767]

Re: QUIKRETE Refractory Mortar Mix

thanks for the tip... i'll keep that in mind!

[rlb444]

Re: QUIKRETE Refractory Mortar Mix

Thanks for the correction Dutch. Yes type N is approx 1 portland, 1 lime, and 3 fine sand. Type S is approx 2 portland, 1/2 lime, 4 coarse sand. I find that the formulas vary depending where you look esp with the sand content. In building my oven I found that the type N mixed 5 to 1 with fireclay works much better than the S mixed 5 to 1. Working with type N is smoother and so is the finish.

[Dutchoven]

Re: QUIKRETE Refractory Mortar Mix

I call it creamier...a mason friend of mine always said use type N unless there is some very specific reason to use something else...a mantra I have tried to remember
Best
Dutch

[slbrickman]

Re: QUIKRETE Refractory Mortar Mix

If calcium aluminate has been added to the fire clay you could experience something called "flash curing".

[MAVANO]

Re: QUIKRETE Refractory Mortar Mix

Ok let me get this, type N mortar mix is- 1part portland 1part lime is it 3 or 6 parts fine sand

[Dutchoven]

Re: QUIKRETE Refractory Mortar Mix

Ok let me get this, type N mortar mix is- 1part portland 1part lime is it 3 or 6 parts fine sand

The recipe for type N for general bricklaying(to the best of my knowledge) is 1portland/1 lime/6 sharp sand...some older mason's around here say between 6 1/2 and 9 parts sand...but again for general bricklaying...for the oven chamber the recipe should be 1/1/3 with 1 part fireclay
Best
Dutch

P.S. As far as I know the Quikrete masonry mortar mix(the just add water type) in Lowe's or Home Depot would be with 6 parts sand