Type S mortar vs Portland cement

[masuzzu]

refractory mortar recipe 1:3:1:1
1 part Lime,3 parts sand , 1 part fireclay and ,1 Part Portland.
Can the Portland cement be replaced by Type S mortar?

[dmun]

Can the Portland cement be replaced by Type S mortar?

No. Type S is a mortar mix, with aggregates already mixed in with the portland. Adding more aggregates would only leave you with a crumbly mess.

[dusty]

No.

Type S mortar is already a mixture of sand, portland cement and lime. You may, however be able to add fireclay to type S mortar to make refractory mortar.

dusty

PS - I mixed my own 1:3:1:1 for setting bricks, but after the first day I cut the lime down to 1/4 part. That stuff is DEADLY nasty!

[masuzzu]

Thanks !
How can I find out the percentage of the sand, cement and lime?

[masuzzu]

What happened when you removed the lime?

[dusty]

Nothing.

But I did't remove it, I just cut it way down. And I used this mix for setting the enclosure bricks, not the oven bricks. For the oven I used store-bought refractory mix. Forno Bravo store.

BUT, when I asked the guy at the cement store about making my own refactory mix, he sugested that the lime content seemed a bit ridiculous. He wasn't a "refectory expert" but he didn't understand the need for that much.

dusty

[dusty]

I forgot to mention that masons quite often add fire clay to their mortar to make it creamier -that is more creamy. He wasn't aware of using it as a refractory additive.

Hope this helps because it seems to be getting rather confusing.

dusty

[Les]

Originally Posted by masuzzu

What happened when you removed the lime?

I thought the lime was to give the mix a more "plastic" nature for workability. I used the suggested receipt and found it to work very well - not as good as HS, but the oven still stands.

Les...

[Dutchoven]

Originally Posted by masuzzu

Thanks !
How can I find out the percentage of the sand, cement and lime?

Type S ratio is usually 9-2-1 sand-portland cement-lime...the sand will only be mixed in if it is referred to as "spec-mix" or the like...you can find just the mortar mix to which you have to add the sand...you could substitute type N mortar(again the mix only so that you can add sand) which will already be premixed of 1-1 of cement to lime...if it is "spec-mix" type N it will be mixed with 6 parts sand...so see if you can get just the mortar mix...you can then simply mix in one part by volume of fireclay to 2 parts type N mortar
Hope this helps!
Best
Dutch