Homebrew 3:1:1:1 - How to work out how much material to buy?

[Robarb]

Fo you think the figures for vermiculite usage is coming out right? Seems i little on the high side, especially if not using a fire blanket. However, i remember you saying people underestimate how much v.lite is actually used.

[david s]

Hello all,

I've slightly modified the original calculator and built a UK/US conversion into it. I haven't quite finished but i think i would like to check the Vermiculite/Vermicrete densities before i do.

david s , when you have a few spare moments are you OK to have a look and let me know what you think?

Thanks

P.s. thanks to 4stroker who lay the good groundwork

Thanks Robard, that looks pretty good although it may be overly prescriptive and assumptions about thickness of various layers will vary for self builders, but it should be useful. Thanks

[Fishman]

Thanks Robarb for the edits and updates for us imperial users!!!

To the moderators, Sticky please!!!

[Robarb]

Hello all,

I've slightly modified the original calculator and built a UK/US conversion into it. I haven't quite finished but i think i would like to check the Vermiculite/Vermicrete densities before i do.

david s , when you have a few spare moments are you OK to have a look and let me know what you think?

Thanks

P.s. thanks to 4stroker who lay the good groundwork

[david s]

About 20%. This is why lots of 1st time builders run out of vermiculite. If you take the volume of vermiculite you use in the mix and add the cement and water, they do not add volume to the mix because they sit in the spaces between the grains of the vermiculite. On mixing the water acts to attract the solid particles together resulting in volume reduction. Best to mix it in a barrow so you can fold the mix gently. If mixed for too long in a mixer it begins to abrade the grains which leads to further reduction in volume. The right amount of water is when it just begins to pool a little in the bottom of the barrow. Usually 3 parts water for every 10 parts vermiculite.The finer the grade the more water is required.

[Robarb]

Thanks david s

From your experience, what would you say the dry volume of an 8:1 vermicrete mix is, compared as to when wet and ready to be moulded/set? How much reduction in volume is there when mixed with water?

I'm adding to Mark's calculator, calculations for a vermicrete insulation layer, and base insulation layer too if i can. It's the last thing i would like to do then i can share here.

[david s]

Not really with you, but the finer materials like clay and cement fill the spaces between the coarser material (sand) so resulting volume is less than the sum of the individual volumes of ingredients. Same goes for the water. On mixing the water in there is also some compaction which also reduces the volume. Is that what you mean?
In practice the sand is rarely completely dry although for the measurements I did use dry sand. Also density, depending on sand type can vary considerably and probably likewise for the powdered clay. Humidity also plays a part. You just need to add sufficient water to get the mix to a good workable “ball up” state. So don’t go by the water content in my measurements.
I do recall there was a shortfall of around 50 g when working out with the densities and put it down to material left behind in the barrow and on mixing tools as well as some evaporation during mixing.
Also the volume measurements were pretty rough, using a kitchen jug so could be out by at least a few%

[Robarb]

Hi 4stroker and david s thanks for your time in putting this together.

I'm just making a few modifcations for info i've come across and for our fellows across the pond and wondered if i could ask something in relation to Note 1, points A and B.

If you have a volume of 1800ml of 4 things prior to dry mixing, and a net volume of those 4 things as c. 1350ml after dry mixing, your net volume is 1350ml. So, when calculating approx water input of 400ml to further reduce the volume to c.1260ml, you're essentially adding the water to the mix (1350ml), not the components (1800ml) separately.

In your excel sheet you work out the 'Approx. total volume of water required' as 'The total dry volume of materials required' (1800ml) * addition of water (400ml) = 0.2222

Should it not be 'Approx. total volume of water required' as 'Resultant volume of materials required' (1350ml) * addition of water (400ml) = 0.2963?

This would in theory make your final density reduction calculation as 'final volume after water addition' (1260ml) / initial dry resultant volume (1350ml) = 0.9333 (not the 0.7 you have in the spread sheet)

I know this is probably minuscule in the calcs but want to make sure i'm thinking correctly.

I hope that's clear as .... clay.

Thanks

[benny8]

I can also add a column/tab for imperial/US units.

What units would you guys want? inches/cubic feet (or gallons?)/pounds?

Stroker, it would be awesome if you could make it cubic feet and pounds for material. Is the current metric version able to change the variables? I tried and it said I needed a password. Thanks a bunch!

[Fishman]

This thread really needs to be a sticky!

[4stroker]

Sorry for the delay, I've uploaded an unprotected version of the spreadsheet now

[david s]

Utah is right, homebrew is not suitable for the floor.use firebricks preferably loose laid.

[UtahBeehiver]

I have not seen successful use of homebrew usage for floors but fine for the dome. Fire bricks are use on the floor section. But you may want to check with David S, he is our casting expert.

[Poochdog12]

i agree, epic work guys. reading how you two worked together to pull up this really helpfull spread sheet was great to read.. ill be using you calculations for sure.. just one question, can i use the same mix to cast the oven floor??

[DBD]

Thanks all, try this.

If anyone finds any errors or issues, please let me know and I will fix.

Unfortunately thanks to Covid-19 I think it will be some time before I "road-test" these calcs...

Hi 4stroker, thanks for uploading this file, super helpful as I was just researching how to make homebrew.

Unfortunately I can't edit the yellow fields in your file, it prompts me for a password :/, any suggestion?