Started the Process - A couple of Questions

[PizzaJNKY]

Re: Started the Process - A couple of Questions

There are no dumb questions. I poured the structural layer, and waited a few days to pour the insulating layer of portland/perlite. I actually poured both slabs the same size, but I think it is better to make the insulating slab smaller, because it is so crumbly. I think it should be be big enough so that your oven fits within it (Hope that makes sence). Check out the Badger build photos, he did it correctly.

[George T]

Re: Started the Process - A couple of Questions

I bought my material for the hearth. Both the insulating hearth and the structural. Can these both be poured the same day? Do I pour both the same size? The instructions say you can pour the insulating hearth smaller....how much smaller? Sorry for all the dumb questions?

[PizzaJNKY]

Re: Started the Process - A couple of Questions

George, perhaps someone else can tell you exactly how much insulation is enough, such as if you use FB board do you still need vermiculite. All I know is that you can't have too much insulation. If you budgeted for FB board, I'd say use both. I used both, a 3-1/2 inches of perlcrete, and then the 2-inch insulation board resting on top of the perlcrete.

[George T]

Re: Started the Process - A couple of Questions

Got the stand finished. And a start on the fireplace structure.....all for today. This afternoon and tomorrow hope to pour the hearth. If I am going to use the FB board, no vermiculite.....correct?

Pictures.
Picasa Web Albums - George - George T's Pi...

[asudavew]

Re: Started the Process - A couple of Questions

I used a 7" saw it can be done...If I had to do it again I would get the 10"...makes life much easier.

I agree with Drake. I used a small saw too.



The mixture wasn't bad to work with at all.

But I topped mine with about a 1/2 inch of high heat mortar.

Here's a picture. You can see the layer on top.

[RTflorida]

Re: Started the Process - A couple of Questions

Never!!!!!!!!

[George T]

Re: Started the Process - A couple of Questions

You guys are amazing. Thanks for the insights. If I use the board I dont use the vermiculite/portland mix right?

PS. do you guys ever sleep?

[dmun]

Re: Started the Process - A couple of Questions

With the seven inch saw it's either cut-and-break, or flip and cut twice. A 10 inch saw makes life easier, no doubt, especially when it gets to any fancy fitting. I have both, (and a 4.5" cheap angle grinder) and I never touch the 7" saw anymore.

Again - the table saw like model throws stuff up in your face. Most disagreeable.

The roughness of the vermiculite layer was the original reason for a slurry (now used as a dry powder layer) of fireclay and sand under the floor: You can get the floor bricks to lay flat.

[Frances]

Re: Started the Process - A couple of Questions

I actually got quite attached to my 7" angle grinder during the build... made it all a bit more of callenge

[DrakeRemoray]

Re: Started the Process - A couple of Questions

I used a 7" saw it can be done...If I had to do it again I would get the 10"...makes life much easier.

[PizzaJNKY]

Re: Started the Process - A couple of Questions

George, the insulating slab goes on top of the structural slab. I made my insulating slab with portland cement and perlite instead of vermiculite, but my guess is they are very similar to work with. I wouldn't worry too much about getting it smooth, I think level is more important. As for the FB boards, mine were delivered within two days of ordering them.

For the tile saw, I concur with RT Florida. The 10" Harbor Freight saw is hard to beat. I bought mine two months ago for $199.

[RTflorida]

Re: Started the Process - A couple of Questions

George, I did not find the vermiculete difficult to work with...even hardened the heavy grained, high clumps were easy to scrape away. I confess to using a wetter slurry coat of heatstop mortar to smooth it out a bit further, don't know if it help much...all in all my hearth bricks came out pretty flat; I think my biggest problem was the size/shape variance of my firebrick (wire cut) - no two bricks were the exact same size.

As for the saw, go for the 10", it will cut through firebrick in one pass; with the 7.5" you will have to flip your bricks over to finish your cuts. The 10" saw from Harbor Freight is a verry reasonably priced workhorse for this task. I got mine just over a year ago on sale for $199 plus $29 for the blade...it works like a champ. Not sure of today's price - may be $229-$249 if not on sale.

RT

[George T]

Re: Started the Process - A couple of Questions

Thanks for all the help.....regarding the hearth. I am assuming you pour the concrete first and then the insulating slab. Is it hard to get the vermiculite portland mixture smooth enough for the fire brick to sit on?

If you order the FB board how long does it take to get?

Also I have a tile saw with a 7.5 inch blade. Will that cut the firebrick? Or do you need a 10"?

Tomorrow we build the stand.

[Frances]

Re: Started the Process - A couple of Questions

Hi George T,

I had exactly the same questions as you starting out... my oven still has the wood support under the hearth - I figured it would stay dry under there anyway. And I put extra rebar over the entrance to the hearth instead of an angle iron, too. And I made as few cuts as possible, like in the plans... if you look around you will see plenty of ovens like that.

If every oven had to end up looking as perfect as like Les', we wouldn't have any new ovens at all....

[SpringJim]

Re: Started the Process - A couple of Questions

don't sweat the inside of the oven look....Les has an awesome dome but looks really don't count when you get to cooking. (they count to the builder and photographer). I have seen some very rough oven domes! The smoother the better for good circulation without friction but to go to the extent that Les did is not necessary for the average oven.

Again, Love your dome and pic's Les....that last brick from dome to chimney throat arch was fantastic...get's my vote for BOMJune

XJ