Dome forms

[jaymac2087]

Hello,
I am just beginning my oven building journey and would like any advise on how to build dome forms for a 42" oven. I have no masonry skills at all and figure that any type of support for the dome would be great. I just don't know how to go about figuring out how to build one. Any help would be great.

[dougrappe]

Re: Dome forms

Hi, take a look at this thread if you haven't seen it already:

http://www.fornobravo.com/forum/f28/...heme-2985.html

I used a similar tool building a 36" pompeii and also found it "indispensible." It keeps the dome nice and hemi-spherical, and is an aid in cutting bricks as well if you go the route of minimal mortar joints. It allows you to set the brick in the mortar bed, maybe hold it for a few seconds until it grabs and then move on to the next one. The nice thing about building the dome is it is self supporting, at least until you get up to the higher courses. A good example of how to deal with that further on in that same thread.

I like this method because you can see exactly the fit you're getting inside of the dome and clean up any excess mortar as you go. There's nothing wrong with using fixed forms, a good example of this in the free e-book/pdf, available here if you don't already have it.

Brick Oven Plans | Build an Italian Brick Oven

Good luck and have fun!

Doug

[fxpose]

Re: Dome forms

I plan on using the above mentioned tool for my build as well but I'm curious about using a form. Which method is faster in erecting the dome for someone who's really pressed for time? Time might be an issue for me as I work over 70 hours per week, although I don't mind dragging the project for months.

[Neil2]

Re: Dome forms

I built an elliptical dome and used Styrofoam as form. A 1/2 inch sheet of Styrofoam is all that is needed and is quite cheap.

[fxpose]

Re: Dome forms

I built an elliptical dome and used Styrofoam as form. A 1/2 inch sheet of Styrofoam is all that is needed and is quite cheep.

Hmm....I remember seeing your form in your Flying Saucer thread. Seems very effective and simple to prep. Much easier than erecting a sand form. How difficult was it to clean up the interior brick faces as you were building?

[Neil2]

Re: Dome forms

Not too bad. If a joint happened directly on one of the styrafom "fins" the mortar got flattened.

Doug's method is good for a hemispherical dome. If you want an ellipse you have to set up some sort of form. Forms are faster as well - you lay the bricks as fast as you want.

[fxpose]

Re: Dome forms

Forms are faster as well - you lay the bricks as fast as you want.

Thanks Neil. That was exactly my thinking. Seems like you can lay bricks this way in no time...
Hmm....got me thinking again...

[DrakeRemoray]

Re: Dome forms

I used forms for my oven build as well, you can see it documented in my oven thread.

If I did it again I would use the indespensible tool as you can make a nicer looking build. Mine is totally functional, but compare my joints to the current builds...

Removing the forms and checking out the joints...

I guess it would be a challenge to get a dome that had the shape mine does, which is a portion of a circle..

Drake

Drake

[fxpose]

Re: Dome forms

That's a very nicely finished oven Drake!

I don't mind filling in the voids on the inside after removing the form. I guess one much also consider, if you do plan on crawling in the dome, dome opening size must be taken into consideration according to your waist size....?

[RTflorida]

Re: Dome forms

fx, if you have kids (or maybe a petite wife), put them to work cleaning/pointing the inside. I played the "guilt card" with my adult daughter who happens to be a size 0-2 and is literally half my size - hmmmmm, maybe NOT really MY daughter........I played up the fact that I was a physical wreck after all the work and all of the things I had done for her.....she slid right in. Although this approach probably will fail miserably on a teenager.

RT

[JoeyVelderrain]

Re: Dome forms

Mitchamus just posted this video. check out their awesome wooden collapsible dome forms.
[/QUOTE]

[jaymac2087]

Re: Dome forms

Doug,
Thank you for the link to "the indispensable tool". It sounds like it would be perfect. You had mentioned that you used something similiar, were you able to purchase it or did you have to make it? I was considering using styrofoam forms but am not sure on how to figure out the measurements. Any help would be great.

[dougrappe]

Re: Dome forms

Further along in that same thread is a picture of my variation on the tool, pretty much stock parts with no welding required, the most complicated part was drilling and tapping a piece of aluminum angle (which isn't even necessary come to think of it now)

about half way down the page:

http://www.fornobravo.com/forum/28/m...me-2985-4.html

there are a few other versions shown and described if you follow along that same thread, so you can pick and choose the bits and pieces that work for you. I hadn't considered using forms since there was just something appealing about seeing the dome go up unsupported, or self-supporting I should say, (not that there's anything wrong with formwork) I thought it went pretty fast, you could do two or three courses in a day I guess, maybe more, depending on how much cutting you do.

Either way, with or without forms you have to be very careful that you don't disturb the recently positioned bricks before the mortar is fully set. I guess with the forms you'd do less damage if you bumped a brick accidentally, since the form would hold it in place.

If you wanted to make forms, I would just use a pencil on a string and set the length to the radius of the desired oven diameter. Depending on the height of the soldier course you'd need to adjust the formwork to make it a bit taller. So the forms wouldn't be exact quarter circles but would be a bit taller than they are wide. I think either way you should to a layout with the actual bricks you are using on a flat surface, so you can visualize the cross section of the dome you'll be building. There's a good illustration of this in the FornoBravo Pompeii plans e-book. (Which I'm sure you've read cover to cover and memorized by now .)

I used angled half bricks for the soldier course so the dome ended up 19" tall inside, even though it's a 36" diameter oven. This would be considered a Tuscan style dome, hemispherical as opposed to the low Neapolitan style. I have no idea how to lay out one of those, seems extra challenging to build too!

Hope this helps,

Doug

[Neil2]

Re: Dome forms

Just like many things there are several ways to do this. In summary:

Indispensable Tool
- Good for hemispherical domes
- Easier to clean inside joints as you go.

Form (wood or styrafoam)
- Better for elliptical domes
- Faster brick laying
- May have to clean up some interior joints when finished.

[Bandrasco]

Re: Dome forms

I used a mason string tied to a screw I had in the center of the dome floor. If you mark it or tie a knot in it at the desired length you can use it to guide you all the way to he top like a champ. Check out my build pics; I believe I have a picture of this in there. It's easier than you can imagine.

Good luck,