Oven Build in SC

[UtahBeehiver]

Re: Oven Build in SC

Videt,

Make yourself a curve trowel to help maintain the dome shape and to the hold in place the v or pcrete during installation. The mix at these ratios are a little crumbly and need to a little help to be held in place.

[videts38]

Re: Oven Build in SC

Gotch ya! Thanks for the advice and the picture. A picture is a thousand words!!!!

[stonecutter]

Re: Oven Build in SC

Like I said, that's hard to accurately say. This time of year, without the humidity and direct sunlight... Maybe a week and a half- two weeks...I don't really know. The trick is to not dry it out to fast, either.

I always build enclosures over ovens, but if I was going to finish it like yours, this is what my schedule would look like.

After completely drying the oven masonry, the ceramic blanket is installed.

I would get some acrylic admixture, Portland cement and dry block additive ....( looks like glue, and is a waterproofing additive for mortar and concrete)....then mix it into a slurry paste, and completely cover the ceramic insulation with it. This will stop most moisture from migrating through the ceramic.

After the slurry dries...(should be dry in a few hours depending on how thick it is and the weather )...then apply the vermicrete layer.

Cover with plastic for a couple days.

Remove plastic and let air dry for a week...covering at night with stand offs to allow evaporation and let condensate to run down the plastic, away from the dome.

Towards the end of the week, I would set up a fan to assist the drying process.

After about a week and a half, I would leave plastic in contact over the dome and check for condensate after a day. That will give you an idea if you can proceed with the drying time or move on to the stucco coats.

I would do at least 1" of stucco, with dry-block additive. I used that product on my chimney stucco ( smooth finish...which leaves less open pores for water intrusion) and the water beads right off.

The final step for me would be a high quality sealer. And, the whole diameter would be flashed...(hidden from sight)

[stonecutter]

Re: Oven Build in SC

Oh for stand offs for the plastic....

Get some rebar caps and landscape staples. Shove a staple into the vermicrete layer, put a cap over it. Remember, you won't do this until a few days after you pour...so the vermicrete will be set up enough by then.

[videts38]

Re: Oven Build in SC

EXCELLENT, that's the info I needed. Now I have some guidelines to go by.

But I do have another question about what you mentioned. Flashing!
How whould that be done? I know what it means but have no idea on how it would be done.
I was concerened about water seeping in at the hearth/dome interface but have not given it any thought yet.

[stonecutter]

Re: Oven Build in SC

Use flexible membrane like ice and water shield. I would cut a 3/4" (deep) line around the perimeter of the oven about 1"-2" off the outermost part of the vermicrete. Insert the membrane into it, and continue around round the perimeter... It would be easier to do the flashing in 3-4 pieces, and make sure your overlap is at least 3". Your flashing should run up the side of the vermicrete no less than 3". Caulk all seams and the joint in the hearth( where you key in the flashing)...them allow the caulk to dry before stucco goes on.


I can't believe I'm giving this away.....I'm suppose to be earning a living doing this!

[videts38]

Re: Oven Build in SC

Can't thank you enough sir. I understand it's very valuble information.
If it means anything- You have earned a friend!

[videts38]

Re: Oven Build in SC

The Curing Fires Have Begun!!!
Got the first layer of insulation on the dome Saturday so I thought it was time!!
I did the 200F (Sat.) and 300F (306F to be exact on Sun.) with the torch I have pictured then today I had my first fire. And I have to say I got a little nervous! I kept hang around 275F to 340F at the dome peak with what I thought was coming up at a decent rate with 1/4"-3/8" pieces
So I put a few more ~1" pieces (4) on it. Well may be I got a little in a hurry because the dome went to ~414F! That's when I decided to knock down the fire by pulling a few of the flaming pieces out and put the door on. The flames were licking the dome!
This happen over the course of ~ 45min. Is this too fast to come up to temp.?, or is it about right? I could use some input from anybody, please. So I won't be paranoid about what's to come!! 500F tomorrow!!!

[mirassou]

Re: Oven Build in SC

Very nice! Enjoy!

[videts38]

Re: Oven Build in SC

Are there any thoughts on how much time it should take to come up to each of the curing temperatures?
And once you get to the desired temp should you snuff the fire?
I got to 400F today and was a little nervous about exceeding it.
500 Tomorrow

[stonecutter]

Re: Oven Build in SC

I never understood that reasoning. Fire your oven at the desired temp for as long as possible.

[videts38]

Re: Oven Build in SC

I just read a post from James that stated "just bring it up to the desired temperature then let the fire die down".
This was posted in 2006- has the thoughts changed since then? just want to do the right thing right!
Also I'm not sure but I don't think it took an hour to get to temp yesterday to 400F. Should there be a ramping up of the temp over a particular period of time?
Yes I'm a newbie to a WFO and I'm a little paranoid of the curing.
More importantly, I don't want a pile of rubble!!

[stonecutter]

Re: Oven Build in SC

Your actual high temps should start out low and get higher every time you fire the oven. The idea is to push water out of the masonry, and you are not 'curing' the oven in the true sense of the word...as it relates to masonry. So, if you are firing the oven to reach a max temp of say, 300*....you will dry the oven faster if you maintain that temp for 5-8 hours vs reaching that temp in 1 hour and letting it cool down. The next time you fire, you'll be able to fire at a higher temp than 400 or 500 degrees.

The trick is not shocking newly the built masonry too much, and the schedule in the FB plan allows a conservative approach to drying....which is a great idea, but not the only way.

Do it the way you are most comfortable or how your time allows. The only wrong way is to over fire the oven too fast, too soon.

[videts38]

Re: Oven Build in SC

Thank you Stonecutter. Tonight I will take it low and slow to get to 500F, say over an hour or so to get to temp. Unfortunately there's no way to maintain that temp. I get home at 5-6 and in bed at 9ish. I work way too much. And now that I wrote it out I'm depressing myself! (lol)
I will maintain for as long as possible.
Here's a thought- Since I can't maintain the desired curing temp for extended periods of time do you think it would help to get to the desired curing temp for a couple successive night? Would it work the same way?
Just a thought.

[stonecutter]

Re: Oven Build in SC

Sure, why not? Even better would be to build a temporary door or pile up some brick in front of the oven opening, to trap as much heat as possible once you turn in.