Forno Bravo Forum: The Wood-Fired Oven Community

Forno Bravo Forum: The Wood-Fired Oven Community (
-   Pompeii Oven Construction (
-   -   Sorry - another Vermiculite Question (

thebadger 03-28-2008 07:47 AM

Sorry - another Vermiculite Question

I did search the threads first and didn't see answers to my question(s).

I'm picking up supplies and my local garden store has both Perlite and Vermiculite (same price $19.99/ 4 cu ft).

The Perlite says "horticultural" grade and the granuals look like pictures I've seen

The Vermiculite has a "check box for horitcultural grade and a check box for fine med course - but nothing is "checked" (the worker says it's "med/course not fine") but the vermiculite looks like it is very small flakes - almost like sand but flatter. I picked up 4 bags but can exchange if needed...

  1. Are the size of Vermiculite flake okay/does it matter?
  2. Should I just go with perlite instead (same price and they have plenty of both)
  3. Is one safer vs the other (I guess a non issue "after" it's installed?)
  4. Can I use a "cheap" drywall mask or should I get a ~$25 respirator?


asudavew 03-28-2008 07:49 AM

Re: Sorry - another Vermiculite Question
I used both.
Perlite and Verm.

The verm. was so much easier to work with than the perlite.
Hands down.
I will NEVER play with perlite again!
It was dusty, fine, and blew everywhere~!

My opinion....

As you were!


gjbingham 03-28-2008 09:51 AM

Re: Sorry - another Vermiculite Question
Try a search on this forum for coarse verm. and one for fine verm. There's been several discussions regarding your question. I believe the medium was generally found the easiest to work with, but don't quote me on that.

I used coarse, without any major issues. The grain size was bb shot size up to twice that size - maybe 4 - 5 mm.

david s 03-28-2008 02:49 PM

Re: Sorry - another Vermiculite Question
I agree ,vermiculite is better to work with, and prefer to use it, but perlite has slightly better insulation value.

thebadger 03-29-2008 04:54 PM

Re: Sorry - another Vermiculite Question
2 Attachment(s)

I did do a search and only found one post about fine vs. course vermiculite. The preference was for for course but nothing "bad" was said/or suggested not to use fine. I want to use this to make my 5-6 inch insulating hearth (going a little thicker) but didn't want to use the wrong stuff. I've attached some pics... Maybe this stuff is "okay" - I just started to question when I saw the different grades on the package (none are marked).

Is this okay to use? I'm assuming the 5 to 1 ration is still okay with this type. Again, the place I bought it from has perlite that looks like the pictures I've seen posted and I can easily exchange it.
Let me know.


Dutchoven 03-29-2008 07:09 PM

Re: Sorry - another Vermiculite Question
I will suggest the use of vermiculite...probably coarse...only because it has a tendency to break up a bit with mixing...perlite is what I used and it blew around horribly and was difficult to get properly mixed...

gjbingham 03-29-2008 08:17 PM

Re: Sorry - another Vermiculite Question
I think it will be fine. I like the idea of six inches of floor insulation too.

thebadger 03-30-2008 04:15 AM

Re: Sorry - another Vermiculite Question

Thanks - I'm doing the 6" insulating hearth for two reasons - extra insulalion and extra height.

Does everyon agree that the 5 to 1 ration is still okay for this "finer" Vermiculite (I'm assuming this is a finer grade)?

Given a 5 to 1 are there any guidelines (in parts) for the water i.e., 1/2 part water? I know it says "an oatmeal consistency..." but I've made some pretty soupy oatmeal in my day.

Thanks for the advice...


thebadger 03-31-2008 10:04 AM

Re: Sorry - another Vermiculite Question

I just called a local pool supply place - he was very familiar with vermiculite as that's what he uses in pool construction.

He told me it's usually fine like sand - but that's not what I've seen in the pictures on the forum???? Hence my confusion/concern.

I am going to order the FB board but would still like to put a small layer 2-3" of vermiculite/concrete down first.

What does everyone think?


asudavew 03-31-2008 10:31 AM

Re: Sorry - another Vermiculite Question
I believe some of the pool vermiculites are coated with silicon, which can create a problem with blending it with cement and water.

Try a local plant nursery and get medium or large course vermiculite.

I got 4 cubic foot bags at my local nursery for about $23.00.

They did have to order it though.... but they received it with their normal delivery.
(Translation - 4 day wait.)

Hope this helps!


All times are GMT -7. The time now is 05:19 PM.

Powered by vBulletin® Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
2006/10 Forno Bravo, LLC