Help! Vermiculite problems

[delay!fox]

Re: Help! Vermiculite problems

Hey Joe,

Sorry for the late response. I haven't been on FB for quite some time. My project has not progressed much since the last photo's where taken. Waiting for the warm weather to come so I can finsih.

On the matter of the opening I'm a little torn myself on how to finish it. Could use some ideas. It's an odd opening and the truth is that if I somehow don't round off the edges it will look to "Boxy" for lack of better words. Do you have any pictures you could share? Could use some helpfult ideas.

[g8rjoe]

Re: Help! Vermiculite problems

Hi delay!fox,

Nice work. I also am building a corner stand like yours. Looks like good craftsmanship.

Curious: How are you finishing the opening below? Ykno, the two 45degreed endwalls in the storage area?

I am thinking of stacking a course of reclaimed brick on the flat side up to the underbelly of the slab just to give it a bit of a more finished look. they fit nicely on the end of the block.

It was also good to read about the vermiculite experience. I have been freaking out thinking I messed it up. But, my slab feels like cork or linoleum.

Cheers,

Joe

[Stiennon]

Re: Help! Vermiculite problems

Beautiful design. I can tell that the ergonomics is going to work out. All that flat space will be very useful. We have to set out folding tables to assemble the pizza on. In the warmer months that is. In the winter we assemble the pizza and eat it inside the house. My job is to stand by the oven and cook the pizza while my wine gets progressively chilled.

[delay!fox]

Re: Help! Vermiculite problems

Hi Steinon,

You had asked that I post some pics of my design. I'm not finished, due to weather, but I posted some photos. I really wanted to get finished but looks like im going to have to wait until the spring.

[Stiennon]

Re: Help! Vermiculite problems

1. High Heat Mortar... did you opt to buy pre mixed or did you make from scratch?

I bought pre-mixed from the same brick supplier that delivered the firebricks.

2. DOME: Couldn't tell from your photo's but is the first row of firebrick MORTARED on to the oven floor?

No. It is just set there. No mortar until the second row.


3. DOME ANGLE: Did you use the a form for the dome, wedges, or free hand? How long did it take you to complete the dome (ie. just the dome, not the insulation, etc.)

Just eyeballed the angles. I build a lot of igloos in the winter here in Michigan so I felt comfortable with that. Took a total of 6 hours to lay up the dome over two days.

4. Did you use the blanket sold at Forno Bravo for insulation?

No. I used more vermiculite+Portland cement. About 4 inches thick. Then I filled the area between the dome and the cemet board walls with loose vermiculite.

5. FIRE BRICK CUTS... How did you cut yours in half and do you think a TILE SAW would work?

I don't think a tile saw will work. I used an abrasive cut-off blade in my 10 inch miter saw. Actually pretty easy. I wish there were a ready supply of half bricks! Or, better yet, special curved bricks for each size dome.



6. Stupid Question: How did you create the diameter of your circle on your oven floor? Can't figure out how to create a 36" Round template?

Held a nail at the center and swung an 18 inch string with a pencil at the end to scribe a circle.

Hope this helps!

-Richard

[delay!fox]

Re: Help! Vermiculite problems

Thanks Steinnon...

Was freaking out... all that time and money, mostly the time. I saw your photo's looks great!!!

As I am about to embark on the DOME, and hoping to finish before the cold weather settles in NY, any advise on DOME Construction.

1. High Heat Mortar... did you opt to buy pre mixed or did you make from scratch?

2. DOME: Couldn't tell from your photo's but is the first row of firebrick MORTARED on to the oven floor?

3. DOME ANGLE: Did you use the a form for the dome, wedges, or free hand? How long did it take you to complete the dome (ie. just the dome, not the insulation, etc.)

4. Did you use the blanket sold at Forno Bravo for insulation?

5. FIRE BRICK CUTS... How did you cut yours in half and do you think a TILE SAW would work?

6. Stupid Question: How did you create the diameter of your circle on your oven floor? Can't figure out how to create a 36" Round template?

Thanks for your help... keep an eye out under my pictures... will post them on my string marked "Greetings from NY".

[Stiennon]

Re: Help! Vermiculite problems

delayfox. Relax! The vermiculite mixture will indeed harden. Within a week it will be as hard as, well, cement! My oven has had no problems at all and is now officially a year old. It is the center of our social life. Last night we made the best calzones ever. Even the french bread came out great. Best crust I have ever achieved.

I like your design. Keep posting pictures as you get to the next steps!

My pictures are here at Flickr.

-Richard

[ross]

Re: Help! Vermiculite problems

its very strange mix - I was worried about mine too

Dont worry ...i found that mine is like cork you can push a sharp knife in and even leave a depression if you push you finger tip on it hard

But after a week or so it becomes quite dense remember the weight of the finished oven is over a large area

the mix was like oatmeal / porridge see a few pics they should set your mind at rest..the mix was 6parts vermiculite - 1 part cement

[delay!fox]

Re: Help! Vermiculite problems

Hello Steinon...

I've got the same exact problem as you and in my third day right now. I'm terrified that I either used the WRONG Vermiculite Product or have the mixture all wrong. How is your Slab holding up with the load of the dome and the other materials???

Did your Slab look anything like mine below? Please comment on Sandy Texture and Color which is a sandy brown. 3 Days in and mine is Wet and Moist as well....

[Stiennon]

Re: Help! Vermiculite problems

Hey, it worked! I am just back from my three week trip to California, China, Hong Kong, Singapore, Tokyo, Seoul. The vermiculite set up very nicely. All of my forms dropped right out.

I did have to cut two of the supports that held up the plywood for the platform with a Skill saw.

Thanks to everyone for their assurances.

[edschmidt]

Re: Help! Vermiculite problems

Im in western michigan and found vermiculite availible at menards. I know it doesnt help with the hearth but it might still help for the loose fill on top of the dome.

[Stiennon]

Re: Help! Vermiculite problems

Thanks for all the input everyone. By the time I left for California the vermiculite was starting to get that firm, cork-like, feel that several of you described. I think I am going to be OK. If I did it again I would leave space around the periphery for some regular concrete just so the edges don't crumble away.

I am looking forward to sharing more with this excellent forum!

-Richard

[Versachi]

Re: Help! Vermiculite problems

I just poured my vermiculite slab this past week and it is now 4 days old and it is starting to get stiff. Was a little worried the day after I poured it that the mix was wrong because it seemed so soft. But now no worries.

John

[Balty Knowles]

Re: Help! Vermiculite problems

Steinnon

Is the slab firm without any loose material? If there's not enough cement then the vermiculite stays loose & can almost be brushed out, If this is the case then I would scrape out the loose material & pour another slab on top of what's left. If you can't scrape it out then it's probably OK. When the pad's cured its still kind of springy, Nissaneill's analogy of cork is a good one

This is how mine looked the first time. I had added too much water & mixed in a mixer, not good, the slab ended up with some loose vermiculite where the cement had kind of washed off. I mixed another batch by hand 5:1 dry first & then less water & re poured another 3" on top of the old slab. I also took this opportunity to install a split brick sub floor

In both cases I seem to remember it setting in a day or 2, maybe I'm wrong but I think I would have freaked out if it was still wet after a week.

Pouring this slab is miniscule compared to the work you'll put in on the dome & rest of the project, not sure of the consequences of building on a soft pad but personally I pour some more.

Regards

Balty

[maver]

Re: Help! Vermiculite problems

Well, the recurring theme here is that everyone who mixes vemiculite cement has misgivings - it doesn't feel right the first time, but generally after a week all is well. Hang in there. Most of the comments here about this can be used if it completely fails, but usually it just works!