Hey all
Great site, just wished I'd found it before I started work on my oven!
At this stage I have cast my dome over a sand mould. It was only after doing this that I realised from reading the posts on castable refractory cement that I have used the wrong product. I cast it instead of bricking for budget reasons- as you may be aware firebricks are not cheap here in Western Australia.
The product I used is a medium weight insulating castable called Shiralite 130MW. Will paste some data below for those of you who understand it.
The reason I used it was that the refractory stockist advised that it was the right product to use and that it was used by local commercial kit makers. Given my reading from this site I am now rather unimpressed with that advice
My questions are these: Will it still work as an oven- what is the effect of using the insulating castable ( I had hoped to use it to make bread and other slow cook items so am wondering about heat retention)? Should I knock it down and start again? (cant really afford to )Or is there something I could do to improve its performance such as render the inside of the castable with non insulating refractory cement?
I had been planning to use ceramic insulation and then vermiculite render on top of the dome I had cast but it would seem that my oven may be insulated enough....
Any suggestions would be much appreciated. Yes I'm an idiot for not reading enough before I started...
Shiralite 130MW
TYPICAL PROPERTIES
Al2O3 ......................................... 46
SiO2........................................... 38
Fe2O3......................................... 1.5
CaO........................................... 11
TiO2........................................... 1.4
MgO........................................... 1.1
Alkalies...................................... 0.6
Maximum Service Temperature (oC): 1300
Nominal Shelf Life: 12 months
Approximate Thermal Conductivity:
oC 250 500 750 1000 1250
W/mK 0.40 0.42 0.44 0.46 0.48
Installation Procedure................... IP/001, 002
Heat Up Schedule........................ HS/002
Bulk Density (kg/m3)
After Heating to 110oC.................. 1550 - 1610
After Firing to 1000oC................... 1440 - 1500
After Firing to 1200oC................... 1560 - 1620
Cold Crushing Strength (MPa)
After Heating to 110oC.................. 5.5 ? 8.0
After Firing to 1000oC................... 3.0 ? 5.0
After Firing to 1200oC................... 3.0 ? 5.0
Modulus of Rupture (MPa)
After Heating to 110oC.................. 2.7 - 6.0
After Firing to 1000oC................... 1.0 - 4.3
After Firing to 1200oC................... 1.9 - 5.2
Permanent Linear Change (%)
After Heating for 24 hrs at 110oC..... 0.0 to -0.2
After Firing for 5 hrs at 1000oC........ -0.2 to -0.5
After Firing for 5 hrs at 1200oC........ -0.5 to -1.5
Maximum Grain Size (mm) 4
Great site, just wished I'd found it before I started work on my oven!
At this stage I have cast my dome over a sand mould. It was only after doing this that I realised from reading the posts on castable refractory cement that I have used the wrong product. I cast it instead of bricking for budget reasons- as you may be aware firebricks are not cheap here in Western Australia.
The product I used is a medium weight insulating castable called Shiralite 130MW. Will paste some data below for those of you who understand it.
The reason I used it was that the refractory stockist advised that it was the right product to use and that it was used by local commercial kit makers. Given my reading from this site I am now rather unimpressed with that advice
My questions are these: Will it still work as an oven- what is the effect of using the insulating castable ( I had hoped to use it to make bread and other slow cook items so am wondering about heat retention)? Should I knock it down and start again? (cant really afford to )Or is there something I could do to improve its performance such as render the inside of the castable with non insulating refractory cement?
I had been planning to use ceramic insulation and then vermiculite render on top of the dome I had cast but it would seem that my oven may be insulated enough....
Any suggestions would be much appreciated. Yes I'm an idiot for not reading enough before I started...
Shiralite 130MW
TYPICAL PROPERTIES
Al2O3 ......................................... 46
SiO2........................................... 38
Fe2O3......................................... 1.5
CaO........................................... 11
TiO2........................................... 1.4
MgO........................................... 1.1
Alkalies...................................... 0.6
Maximum Service Temperature (oC): 1300
Nominal Shelf Life: 12 months
Approximate Thermal Conductivity:
oC 250 500 750 1000 1250
W/mK 0.40 0.42 0.44 0.46 0.48
Installation Procedure................... IP/001, 002
Heat Up Schedule........................ HS/002
Bulk Density (kg/m3)
After Heating to 110oC.................. 1550 - 1610
After Firing to 1000oC................... 1440 - 1500
After Firing to 1200oC................... 1560 - 1620
Cold Crushing Strength (MPa)
After Heating to 110oC.................. 5.5 ? 8.0
After Firing to 1000oC................... 3.0 ? 5.0
After Firing to 1200oC................... 3.0 ? 5.0
Modulus of Rupture (MPa)
After Heating to 110oC.................. 2.7 - 6.0
After Firing to 1000oC................... 1.0 - 4.3
After Firing to 1200oC................... 1.9 - 5.2
Permanent Linear Change (%)
After Heating for 24 hrs at 110oC..... 0.0 to -0.2
After Firing for 5 hrs at 1000oC........ -0.2 to -0.5
After Firing for 5 hrs at 1200oC........ -0.5 to -1.5
Maximum Grain Size (mm) 4
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