Defining the terms "Cement Fondue" & "Calcium Aluminate Cement"

[Lburou]

I'm not sure in every case what is meant by "Ciment Fondu".

At the Wesco refractory, they called it 'fondu' and said I could use it for mortar. The bag I bought is labeled 'calcium aluminate cement'. There are instructions for accelerating cement on the bag.

As an aside, this refractory makes a castable refractory cement: The owner mentioned a simple castable refractory recipe that included this calcium aluminate cement plus aggregate and something else.

I see Australians use the term ciment fondu....Is it the same type of product?

Regardless of the down side of a quick set, I'm going to experiment with it and see if I can't use it in my home brew mortar (reducing the lime portion as necessary if it sets too fast). I'll be building the dome in 70F weather real soon, so I don't expect a set time that is too rapid like when it is hot outside.

What is your experience with calcium aluminate cements (in home brew mortar)?

[Wiley]

Re: Defining the terms "Cement Fondue" & "Calcium Aluminate Cement"

Lee,
I used calcium aluminate cement in the refractory for my WFO. It was called Fondu. There is no final "e" on the name, here's a link:
Kerneos Inc.

I think the word "fondue" has to do with a melted food (cheese or chocolate) into which one dips pieces of bread or fruit etc.

There has been a bit of discussion on the subject I would suggest checking the archives and/or my thread: "Steel Dome Oven".

Bests,
Wiley

[Lburou]

Re: Defining the terms "Cement Fondue" & "Calcium Aluminate Cement"

Thanks Wiley....Kernos is the manufacturer of my fondu cement. I changed the spelling in the OP soas not to confuse anyone else. I did a search, but didn't find what I was looking for. I'll be substituting the fondu for portland in the home brew....I'd like to hear from those who have done the same.


Next time I visit Wesco refractories, I'll get the recipe for a castable refractory mix so we can make our own castable home brew using the fondu cement.

Lee,
I used calcium aluminate cement in the refractory for my WFO. It was called Fondu. There is no final "e" on the name, here's a link:
Kerneos Inc.

I think the word "fondue" has to do with a melted food (cheese or chocolate) into which one dips pieces of bread or fruit etc.

There has been a bit of discussion on the subject I would suggest checking the archives and/or my thread: "Steel Dome Oven".

Bests,
Wiley

[david s]

Re: Defining the terms "Cement Fondue" & "Calcium Aluminate Cement"

Apparently it is the ingredient added to rapid set concrete. When used with either portland cement or lime you will get a reaction that speeds up the setting time. The trade name is Ciment Fondu.

[david s]

Re: Defining the terms "Cement Fondue" & "Calcium Aluminate Cement"

Lee,
Even the smallest amount of lime combined with the calcium aluminate cement will act as an accelerant. I think you are better to eliminate the lime entirely from the mix, but by all means try it for yourself. A popular castable mix for kiln castable parts is 5 parts crushed firebrick to one part cal. Alum. Cement by volume. proprietary castable refractory mixes contain fly ash, and aggregates (grog which is crushed fired fire clay capable of standing up to thermal shock and fibres which burn out to create holes where moisture can escape) Making up your own brew is a difficult task, probably better to stick to a proprietary mix rather than invent your own which may fail.

[Lburou]

Re: Defining the terms "Cement Fondue" & "Calcium Aluminate Cement"

Thanks David

I will do some test mixes prior to starting.

I'd still like to hear from someone who has elected to use the home brew with the calcium aluminate option.....Anyone?

[Lburou]

A report on "Ciment Fondu" & "Calcium Aluminate in 'Home Brew' mortar

Well, I'm almost done with my dome and have been using the home brew with the calcium aluminate option. No regrets.

It worked well with a little cautious experimentation. When we get to the lime container, we use about one fourth or one fifth of a measure and it set in 5-15 minutes, depending on the amount of water added. The outside air temperature has run between 55 F and 80 F. It does set up faster the warmer it gets!

It seemed easy enough to use, just don't mix too much at one time, one half a liter to one liter worked well for us.

BTW, leaving the lime out entirely allowed us 15-20 minutes working time, which is too long for me when you get up to the steeper chains of your dome. HTH

[david s]

Re: Defining the terms "Cement Fondue" & "Calcium Aluminate Cement"

"one half a liter to one liter "

So what were the proportions and materials of your final recipe?

[Lburou]

Re: Defining the terms "Cement Fondue" & "Calcium Aluminate Cement"

"one half a liter to one liter "

So what were the proportions and materials of your final recipe?

Hello David

The recipe in the pompeii plans is:

1 part calcium aluminate (we used ciment fondu)
3 parts sand
1 part fire clay (we used hawthorne blend clay)
1 part lime (....I don't recommend any lime!....)

We used that recipe, but withheld 75% of the lime recommended (working in the 55-80 F temperatures).

The recipe, without lime, set in 15-20 minutes if you don't water it down.
Heeding your cautions about use of lime, we were cautious with the lime and found that using 25% the recommended rate of lime worked for us at those temperatures. In the end, we eliminated lime altogether.

We dry mixed a gallon sized bucket of ingredients, then mixed small amounts taken from that dry mix with water. We used about half or one liter of the dry mix as needed and added water, that way we always had fresh mortar. Our mortar would hold most bricks after four or six minutes, except the last few chains....We are taking longer up there.

ADDED:

For the last four or five chains, I inserted a pilates ball and didn't have any more problems holding bricks in place -I recommend this without reservation.

I can imagine this mixture setting in <one minute at 90 F if using the original recipe.

I used this process to take advantage of the improved heat absorption and heat holding characteristics supposedly found in this mixture over the Portland option. More than one member has recommended eliminating the lime from the FB pompeii plan recipe....I see both sides of the issue.

Thanks David for your caution about use of lime in this mixture, we took your advice and went slowly.

ADDED:

When you accelerate cement (concrete), there is a tendency to form small cracks on the surface of the concrete because of the rapid shrinkage. I have noted some tiny surface cracks in the mortar but do not expect any leaks or other problems. That is the only down side so far.

[jgestner]

Re: Defining the terms &quot;Cement Fondue&quot; &amp; &quot;Calcium Aluminate Cement&quot;

I am waiting for some pics of your build.

In the mean time can you or someone else tell me what you use the lime for in this mix? I was under an uneducated assumption that the Ciment Fondu was a complete refractory cement solution.

My interest is in using The Ciment Fondu or HeatStop 50 or any similar product for a self cast oven, most likely in several pieces.

I wonder if it would be acceptable to add the sand and/or some clay to the refractory cement in self cast pieces for a WFO? The idea being to get some more product for the oven pieces at a lower price. Or would the sand and clay weaken the pieces too much for self standing cast oven pieces?

Thanks for any comments or wisdom on materials and methods.

John
Merrill, WI

PS I think my local Cement provider has quoted me $68.00 for what they are calling a 40 pound pail of HeatStop II, (that seems kind of high and I haven't seen reference to a 40 pound package anywhere else).

[Lburou]

Re: Defining the terms &quot;Cement Fondue&quot; &amp; &quot;Calcium Aluminate Cement&quot;

You can click on my name and go to 'Albums' for pictures of my oven.

I would not put lime in under any circumstances, the manufacturer recommends never adding lime to ciment fondu.

You are truely opening a can of worms making your own castable mixture. If you visit a refractory, they will sell you the castable mix you need to cast your own oven.

During a visit to my local refractory, I spoke with the owner and his engineer about a home made castable for my best friend working overseas where materials are not readily available. This is the home brew recipe they gave me -use at your own risk:

• 30% Ciment Fondu (calcium aluminate cement I'm sure you can get some)
• 60% Aggregate (#6 mesh -sizing 3mm down to powder)
• 5-10% Fine Sand
• 5-10% kyanite (crushed, Metamorphosed peri-aluminous sedimentary rock, optional, if not available locally-add more fine sand)
  
  
  

I am waiting for some pics of your build.

In the mean time can you or someone else tell me what you use the lime for in this mix? I was under an uneducated assumption that the Ciment Fondu was a complete refractory cement solution.

My interest is in using The Ciment Fondu or HeatStop 50 or any similar product for a self cast oven, most likely in several pieces.

I wonder if it would be acceptable to add the sand and/or some clay to the refractory cement in self cast pieces for a WFO? The idea being to get some more product for the oven pieces at a lower price. Or would the sand and clay weaken the pieces too much for self standing cast oven pieces?

Thanks for any comments or wisdom on materials and methods.

John
Merrill, WI

PS I think my local Cement provider has quoted me $68.00 for what they are calling a 40 pound pail of HeatStop II, (that seems kind of high and I haven't seen reference to a 40 pound package anywhere else).

[dmun]

Re: Defining the terms &quot;Cement Fondue&quot; &amp; &quot;Calcium Aluminate Cement&quot;

I think my local Cement provider has quoted me $68.00 for what they are calling a 40 pound pail of HeatStop II

That smells like a wet premix to me. Stay away. Heatstop, the dry stuff, comes in ten pound pails or fifty pound bags.

HeatStop 50 or any similar product for a self cast oven

Heatstop is a mortar, not a castable product.

[david s]

Re: Defining the terms &quot;Cement Fondue&quot; &amp; &quot;Calcium Aluminate Cement&quot;

JGestner,
What you are chasing is known in the trade here as castable refractory. As Lburou advised creating your own brew is risky, i"d stick with a ready mixed product, it may be more expensive , but at least you know it will work properly. There are all kinds of goodies they put in the mix to make it perform.

[jgestner]

Re: Defining the terms &quot;Cement Fondue&quot; &amp; &quot;Calcium Aluminate Cement&quot;

Yes I am starting to understand that calcium aluminate would need to be mixed with the proper measures of aggregates to create a dependable castable refractory material.

I am just trying to find all of the different acceptable materials, premixed or not, to use for casting oven pieces.

Then which are available to me in the middle of Wisconsin.

And then it would be nice if it was less expensive than what my local Concrete company quoted me, ($68 US /64.688 AUD for 40 LB/ 18.1 Kilo Pail of HeatSet II).

More research is cheaper than jumping in with what I have been offered as of today. I also have a suspicion that many different companies are selling many products that might work just fine, but all at different prices and availabilities to me.

Thanks for any insight, I need a lot more before I jump into this project.

John in Merrill

[david s]

Re: Defining the terms &quot;Cement Fondue&quot; &amp; &quot;Calcium Aluminate Cement&quot;

I have been down the same road. The manufacturers like to keep their recipes secret so finding out the actual recipe is difficult. They use fired crushed clay which will not shrink like unfired clay. This is an advantage because when you cast, depending on how you have set up your mould there will be virtually no shrinkage.They use fly ash, one characteristic this gives is to make the mix more fluid during work up so you don't need so much water addition. They use fibres which burn out at 160 C, so you are left with tiny pipes that water can escape from during curing to avoid blowing.Who knows what else is the brew? You would need to add these ingredients in the correct proportions too. It would take you ages to mix all this stuff up. I find it is easier to buy the stuff premixed.At least you know it will work.