36" build in Tallahassee - AKA Bruce's Folly

[Bec1208]

Re: 36" build in Tallahassee - AKA Bruce's Folly

Great to know thanks. Bruce

[Bec1208]

Re: 36" build in Tallahassee - AKA Bruce's Folly

I pulled up WG's data sheet. They describe both the red and buff (the $2 brick) as light duty and indicate the red brick is good for operating temps up to 1750 f and the buff to 2000 f. Interesting there is only about a 1.5% difference in alumina (27.6 - 26.1). The buff brick feels much harder and the surface is smoother. Still, based on the data sheet it certainly looks like the red will work. Thanks again vtsteve for your response.

[cobblerdave]

Re: 36" build in Tallahassee - AKA Bruce's Folly

Gudday Bruce
Easy to remove arch guide. Measure out your size /shape and cut out 2 pieces of ply/chipboard etc, make sure you factor in less in height to account for a couple of thin shims under the bottom.
Screw a couple of battens of wood on to the first template horizontally. Screw the secound template to the wood battens. Take you saw and set to cut through the depth of you template material. Cut through both side of the templates vertically.
The resulting guide now is held together by the wood battens and when the arch is finished is a case of unscrewing the pieces for removal. I have used this twice now and it works well and doesn't take much effort to build.
Screw the arch guide back together and keep it for a door template. As for a door, mine weights 9 kg that's a little heavy and I suspect other types are a little weighty as well. It will just have to be one for the forum when the time comes.
Regards dave

[Bec1208]

Re: 36" build in Tallahassee - AKA Bruce's Folly

Well I think Einstein got it right. I decided to start cutting the first ring of firebrick using the side angle (5.3) and inner and outer bottom brick widths (3.25" and 4"). I had put together a jig to angle the brick and penciled on the outline. I ended up with two pieces that had only fleeting resemblance to what was intended. The second attempt came closer, but looks like the learning curve is a bit steeper then I expected. Anyone have a link to a remedial guide to brick cutting or instructional video? I'm going to go out and try cutting a few more bricks and see what happens. Bruce

Edit: I forgot to credit deejayoh's pompelli dome calculator - http://www.fornobravo.com/forum/f28/...tor-18131.html

It has been very helpful in helping understand the process of cutting and tapering bricks.

[Bec1208]

Re: 36" build in Tallahassee - AKA Bruce's Folly

A little bit more practice made a big difference. Cuts became smoother and bricks looked like trapezoids. I decided to put them on the cardboard pattern so I could admire my new competence. Whoops (see image 1)

I cut one edge off a brick and used an app on my IPad to check the angle. It turned out the angle was 8.7 deg. I decided to apply a little theory. I used side angle side formula from trig to solve for the distance to raise the guide bar off perpendicular. It worked out to be .65" measured 7" from the pivot. I drew a line along the bar using a brick laid against the blade to set the bar to perpendicular. Then I found a point .65" above the first line and 7" from the pivot moved the guide bar to this position. I used a wood screw to lock it to this angle since it will be used to cut the first and second courses. The results are seem in image 2, looks good to me.

Here is a site that has a calculator to solve trig problems like the above.

TRIANGLE CALCULATOR Solves 4 Cases of Triangles - SSS - SAS - ASA - AAA

This method seems to be a good method to set the angles on the and could also be used for the vertical angle. Is there an easier or more accurate method?

[cobblerdave]

Re: 36" build in Tallahassee - AKA Bruce's Folly

A newbie?s survey of the Forno Bravo treasures hiding in the archives
Gudday Bruce
This might help. It's called Deejayohs dome calculator found in "newbie section"
"A newbie survey of the forno bravo treasures....." ( if my link don't work.
By the way you have seemed to figure it out youself all right so you understand. Regards dave

[Bec1208]

Re: 36" build in Tallahassee - AKA Bruce's Folly

Dave, hello again. Actually I realized I had not credited deejayoh's dome spreadsheet in the earlier post and have already edited it. I agree it is very helpful and a great contribution to the site. In the posts I've read regarding the building and use of jigs, I recall anyone having trouble setting the angle for the guide bar. Makes me think I am missing some obvious method. Still my approach seems to work and does not require and special tools (just a ruler). Also thanks for the arch instructions. I decided I better cut a few bricks before becoming too caught up in the arch setup. Thanks again, Bruce

[Bec1208]

Re: 36" build in Tallahassee - AKA Bruce's Folly

Feels like a productive day. Once I got the jig set, the cuts went quickly. Didn't seem like there was too much dust, though a pretty good spray of water and mud emitted away from the saw. I finished the ring that will surround the oven floor (image 1). With a bit more experience I suspect most people draw the pattern on a brick and eyeball the setup. Curious to see the real answer, probably over thinking this.

I'll be back with a few questions regarding the next step after a break for dinner. Grilled salmon, potato salad, broccoli salad, and baked beans. All the sides were made my my wife.

[Bec1208]

Re: 36" build in Tallahassee - AKA Bruce's Folly

Thinking about tomorrow's focus. Seems like I have some options.

1: Start by laying out CF board on stand. Then lay out floor bricks and trim to 36" circle.

2: Layout floor on cardboard template. Trim to 36" circle and number bricks for later transfer to hearth. Then, layout CF board, maybe spread butter over the top per Brickie's suggestion (anyone tried?) to keep board from sucking moisture from leveling slurry, and transfer floor bricks.

In either case, once floor is set on insulation, should surround ring of firebrick be mortared to each other and to top of insulation of just to each other?

Thanks for any input. Bruce

[cobblerdave]

Re: 36" build in Tallahassee - AKA Bruce's Folly

Gudday Bruce
Yes the margerine trick works well in sunny hot conditions.
36 in internal ? Why don't you put down a piece of ply the size of internal to fix you Indispensable tool to. Cut it into small enough section to fit out the door at the end and screw it back together with battens. The base bricks for the dome and entrance should be cemented to each other but not the hearth and leave the dome able to expand seperate to the hearth( less chance of cracks).
Hope this helps
Regards dave

[brickie in oz]

Re: 36" build in Tallahassee - AKA Bruce's Folly

maybe spread butter over the top per Brickie's suggestion (anyone tried?)

Thank cobblerdave not me.

[Bec1208]

Re: 36" build in Tallahassee - AKA Bruce's Folly

Ah, memory I almost remember when I had one. Hi brickie, I hadn't"t relalized you were the author of the kindle book I purchased a few month ago until yesterday. Do you stil manage the website you mentioned at the end of,the book? I couldn't get the link to work. Regards, Bruce

And thanks cobblerdave for the tip. Bruce

[Bec1208]

Re: 36" build in Tallahassee - AKA Bruce's Folly

Dave, sounds like you recommend setting the CF board and floor first (wouldn't I need to before laying the plywood?). Thanks

[brickie in oz]

Re: 36" build in Tallahassee - AKA Bruce's Folly

Ah, memory I almost remember when I had one. Hi brickie, I hadn't"t relalized you were the author of the kindle book I purchased a few month ago until yesterday. Do you stil manage the website you mentioned at the end of,the book? I couldn't get the link to work. Regards, Bruce

Thanks for buying the book Bruce.

I deleted the website because unfortunately I had to many spammers and scammers coming to the site, it was wearing me down,
I did the site to help ppl understand brickwork but there are too many scammers wanting to take advantage.

[Bec1208]

Re: 36" build in Tallahassee - AKA Bruce's Folly

Sorry to hear. Thanks for your help. Bruce