Vermiculite (Grade #3 or #4)

[Saovicente]

Ladies and Gentlemen,

I have been pouring over threads searching for for a concrete () number on which grade of Vermiculite to use for top and bottom of a build. ( I "of course" may have missed it or not poured thru enough posts)

As I have read and been told, the higher the number, the coarser the material and that it is better for insulating purposes for the vermiculite to be loosely poured over the ceramic blanket/dome.
Questions:
1) Which grade would be more efficient to mix with Portland for on top of the slab?

2) Which grade would be more effective for the top of the ceramic blankets/dome.


Thank You,

Sandro

[david s]

Re: Vermiculite (Grade #3 or #4)

I've tried coarse, medium and fine vermiculite and all work ok for a 5:1, but for a leaner mix like 10:1 I've found the finer stuff works better. Some have argued that the coarser stuff would theoretically insulate better. I'm undecided about this and any difference would be marginal anyway. The amount of cement mixed with the stuff is a far greater factor affecting insulation value. I've found the best mix for a lean brew to be a 50/50 mix of medium perlite and medium vermiculite and I also now throw in a handful of powdered clay with every litre of cement to improve workability. The correct amount of water in the mix is critical. I use 3 litres of water for every 10 litres of vermiculite, but if you use the fine grade it requires more water which of course has to be removed after.

[stonecutter]

Re: Vermiculite (Grade #3 or #4)

The ideally, aggregate on any mix design is graded, with fine-course particles.

[david s]

Re: Vermiculite (Grade #3 or #4)

The ideally, aggregate on any mix design is graded, with fine-course particles.

Yes, this is probably why my vermiculite/perlite mix works well because the larger grains of perlite are balanced with some variable grain sizes of the vermiculite.

[Saovicente]

Re: Vermiculite (Grade #3 or #4)

Gentlemen,

I appreciate the knowledgeable know-how: I am getting closer to bringing all the pieces together to break ground on this outdoor creation.

Onward's to perfecting an insulated "cost-saving" creation

The intellects:
David:
I've found the best mix for a lean brew to be a 50/50 mix of medium perlite and medium vermiculite.


Stonecutter:
The ideally, aggregate on any mix design is graded, with fine-course particles.

Based on what I have read: It is to my advantage to create a 50/50 (Perlite( fine, medium or course) / Vermiculite (Fine, medium or course) mix.

I am still trying to understand the numbering of which is which (I assuming medium #3, course #4) hmmm, I need to find out where is 1 and 2 in all of this

I will call the manufacture tomorrow and get a better understanding of the numbering system.

I have not asked around for info on perlite, but the distributor I am dealing with gets the vermiculite from the same manufacture whom also makes perlite. Will get pricing tomorrow.

As always, I sincerely thank you for your thoughts, which are much appreciated.

Sandro

PS: I have attached two *.pdf for review for other newbies who comes upon this thread. The data may be of interest. The information is from a company which manufactures both products in MA (US).

[stonecutter]

Re: Vermiculite (Grade #3 or #4)

For what it's worth ( probably not much) I have used both, I prefer Perlite.

[david s]

Re: Vermiculite (Grade #3 or #4)

For what it's worth ( probably not much) I have used both, I prefer Perlite.

Except that it contains some fine powder, presumably fine perlite particles that are irritating if you breathe them. Vermiculite doesn't seem to have these small airborne particles.

[stonecutter]

Re: Vermiculite (Grade #3 or #4)

Except that it contains some fine powder, presumably fine perlite particles that are irritating if you breathe them. Vermiculite doesn't seem to have these small airborne particles.

Everything has dust that can be irritating, including vermiculite...and if you are using fine grade, you'll get plenty of it.

[david s]

Re: Vermiculite (Grade #3 or #4)

Everything has dust that can be irritating, including vermiculite...and if you are using fine grade, you'll get plenty of it.

That may be true, and the manufacture of these products will vary from place to place, but the perlite tha's available to me has the irritating dust while the vermiculite doesn't have any. Can't speak for your supplier.

[stonecutter]

Re: Vermiculite (Grade #3 or #4)

I can get both kinds. Block fill perlite is fine and dusty, horticultural grade has almost no dust at all... Which is what I used.

[Saovicente]

Re: Vermiculite (Grade #3 or #4)

Gents,

I have spoken to a technical person from the manufacture of perlite and Vermiculite in my area and his recommendations are as follows.

Use #2 vermiculite when mixed with Portland cement (provides a more cohesive, comprehensive strength. "more cement around the particles"
#3 is also great to use but 2 for "better" comprehensive strength.

If using Vermiculite loosely, then #4.

I will keep the both of you updated when I create a thread dedicated to my build. I will aspire in creating an efficient, effective oven (love those two words).

Please keep those thoughts coming. You are the experts in this intimate field of works, so keep feeding me.

Now on to find a size for a barrel oven (any thoughts),so I can break down the costs of all materials and report back to the boss.

Sandro

[david s]

Re: Vermiculite (Grade #3 or #4)

The size of your oven is totally up to you, what you want to cook and how you cook. I'm a fan of small ovens because you use them more frequently, require less materials, cheaper and quicker to build and use less fuel. However if you want to cook a whole pig or bake bread for the whole village you might prefer a large oven.

[stonecutter]

Re: Vermiculite (Grade #3 or #4)

The size of your oven is totally up to you, what you want to cook and how you cook. I'm a fan of small ovens because you use them more frequently, require less materials, cheaper and quicker to build and use less fuel. However if you want to cook a whole pig or bake bread for the whole village you might prefer a large oven.

+1 Try to think about what you want, go from there.

[Saovicente]

Re: Vermiculite (Grade #3 or #4)

Thnkk you Gents,

I have thought about it over and over and I believe the most important item on my list is heat retention. I want the option (I love options) to cook up a pizza, than move on to something else, or wait till the next day + to roast or bake.

I do want an ample size oven for those few times it may be needed for that succulent ???. (whatever....As long as it is big and a great excuse to use the oven) I may even let my neighbor use it, if he behaves.

I have re-read brickie in Oz and WJW threads and I may incorporate a few things from each built into my own (size, insulating bricks, thermocouples (which is a must - Will do further research for a cost effective solution)
My struggle is find a comfortable base within the two size differences of their oven and come up with specs to work with (L, W, internal dome size, door entry L- W (the magical 63%)


Per example (Brickie in Oz) used pavers in the middle of ceramic boards and firebricks to add thermal mass. He used insulating bricks to break the connection between the oven and the supporting structures, easing the heat load, etc.

I can go on but you guys know of the builds: and of course I will work on molding a flue like David's. I do not want to see soothe coming out of the front. I have always seen that as a negative, some may disagree but to each his or her own on that.

[Saovicente]

Re: Vermiculite (Grade #3 or #4)

Gents,

I recently acquired some olden chimney bricks (average 7lbs each).
My thoughts are to use them for the outer arch, brickies thermal mass idea, enclosing the oven for the vermiculite payload or decorative means.

Any better ideas of the best way to utilize them would be appreciated.

Any thoughts on the best method to clean them up a bit, other than scraping the dried mortar off ( I want to keep the aged look)

I have read pics are welcomed, so I added one for the visual fun.

Best regards,

Sandro