Who has used the calcium aluminate option for mortar?

[shuboyje]

Re: Who has used the calcium aluminate option for mortar?

I didn't mean to make a comparison, sorry if it somehow came out that way. My point is the only reason to use calcium aluminate IMHO is if there is some issue with the standad home brew you are trying to avoid. I've found no such issue after building two ovens with it and inspecting one after about 100 firing. Calcium aluminate is more expensive, harder to find, harder to work with, and calcium aluminate mortars seem to be more prone to cracking based on observations on this forum. If our application does not require it for structurally integrity why use it?

[Piscatorsalmotrutta]

Re: Who has used the calcium aluminate option for mortar?

Hi picked up your thread, I am using Ciment Fondu from Kerneos Inc. . I am using their aggregate called "Alag" in Fine and Coarse mixture. The mix will be 3 x Alag to 1 x Ciment Fondu. dry mix for min 6 minutes and then radually add water until a good flow in the hand is achieved. Grab some wet cement and bounce it in your hand, it should be firm but not too wet or dry. I was told I will, with limited experience know when it is right. When cast this will be good for temps in oven to 1200 deg. Advice came from a team member in their Purfleet office, here in Grays, Essex, England. I have not cast yet still prepping. The materials to cast will be the only new product I will use as I am attempting to use recycled products that are surplus from local building projects.
I will in due course be posting some pictures. I will be using wet sand as the mould,base diameter 36 inches, dome height 40, entrance height to oven 23 inches. Diameter of entrance 16inches. Above wet sand I will be placing at least 3 sheets of wet newspaper.
I was advised that if casting in above 25 degrees to assemble a shade and to spray the cement to stave off too rapid hydration. I am told it "goes off" in a little over 2 hours and therefore workable to my needs. A little apprehensive as I have never attempted anything like this before but......
Piscatorsalmotrutta (trout fisherman!)

[david s]

Re: Who has used the calcium aluminate option for mortar?

I didn't mean to make a comparison, sorry if it somehow came out that way. My point is the only reason to use calcium aluminate IMHO is if there is some issue with the standad home brew you are trying to avoid. I've found no such issue after building two ovens with it and inspecting one after about 100 firing. Calcium aluminate is more expensive, harder to find, harder to work with, and calcium aluminate mortars seem to be more prone to cracking based on observations on this forum. If our application does not require it for structurally integrity why use it?

Yes, I agree with everything you said.

[david s]

Re: Who has used the calcium aluminate option for mortar?

Trout fisherman,
When you first start using the stuff do not make up too much. You can make up small batches as you go, the stuff goes off pretty fast and is expensive so don't waste any.I find covering the casting in cling wrap as soon as it's finished works well to lock in the required moisture for hydration. Curing for 24 hrs is all that is required because the hydration is complete in that time. You can then remove it from the mould.

[Piscatorsalmotrutta]

Re: Who has used the calcium aluminate option for mortar?

Hi David S, I plan to cast the mix over a sand mould in one go, I was a little worried that doing it i steps it might not bond correctly, I was planning on mixing my 3 to 1 twice and immediately casting it over the sand mould. I have now emailed Genine, the scientist at Kerneos who has been kindly advising me. I thought I would have a couple of wt hours to work the mix over the mould and get it right, so to speak.
Piscatorsalmotrutta (Trout fisherman!)

[Lburou]

Re: Who has used the calcium aluminate option for mortar?

Hi David S, I plan to cast the mix over a sand mould in one go, I was a little worried that doing it i steps it might not bond correctly, I was planning on mixing my 3 to 1 twice and immediately casting it over the sand mould. I have now emailed Genine, the scientist at Kerneos who has been kindly advising me. I thought I would have a couple of wt hours to work the mix over the mould and get it right, so to speak.
Piscatorsalmotrutta (Trout fisherman!)

Interesting tack you have taken....PLEASE, share the advice you get from kernos.

[david s]

Re: Who has used the calcium aluminate option for mortar?

If you do it in one go, then make sure you have some assistance. If the mixture begins to harden any added water to keep it fluid enough to be workable will simply reduce it's strength. If you do it in batches it should be still soft enough to bond well to the next layer. Do wash out your barrow or mixer each time though, because any material that has gone off will accelerate the new batch. I was just trying to help you save waste and $
Ps I use a satay stick to check the correct depth, works well.

[Lake lover]

Re: Who has used the calcium aluminate option for mortar?

Lburou

Are you going to use an outer mold ? Or mix it thick enough so it supports its self till it sets up ?

How thick are you trying to get the wall ? Are you castin the door and flue at the same time ?

Thanks I'm a Newbie here, trying to find materials is a pain.

[Lburou]

Re: Who has used the calcium aluminate option for mortar?

Lburou

Are you going to use an outer mold ? Or mix it thick enough so it supports its self till it sets up ?

How thick are you trying to get the wall ? Are you castin the door and flue at the same time ?

Thanks I'm a Newbie here, trying to find materials is a pain.

You must have been asking Piscatorsalmotrutta this question, no?