The Backofen

[deejayoh]

Re: The Backofen

I wasn't trying to be mean, just reiterating my thoughts. Thoughts we discussed on the telephone, and were not pointed at your remarks deejayoh.

no worries. I didn't take your comment as mean or critical in any way. apologies if my remarks came across as defensive. It's all good conversation

[Lburou]

Re: The Backofen

I agree you can get a good build either way. My suggestion to taper was based solely on the use of HS50. At $80-100 per bag, the return on tapering is that mortar goes much further. If you are using homebrew then the cost vs. time equation is less compelling.

I wasn't trying to be mean, just reiterating my thoughts. Thoughts we discussed on the telephone, and were not pointed at your remarks deejayoh.

[deejayoh]

Re: The Backofen

I would not taper my bricks again. It was a lot of effort with little return. Also, I would not attempt a tiny mortar seam on the inside of the oven (that makes it impossible to completely chink the openings between the bricks with mortar. At least one forth inch of mortar between bricks has worked fine in many a good build. Those are a couple of my observations in hindsight, I hope they are useful to you.

I agree you can get a good build either way. My suggestion to taper was based solely on the use of HS50. At $80-100 per bag, the return on tapering is that mortar goes much further. If you are using homebrew then the cost vs. time equation is less compelling.

[Lburou]

Re: The Backofen

Thanks guys .. I am on my way to HD to get the materials for the IT and a new saw blade. will post progress this evening .. thanks again!

I see the Kissing Camels in your signature! Lived one mile from them for 15 years, lots of good memories rock scrambling with my grandchildren.

[Coloradoredusa]

Re: The Backofen

Thanks guys .. I am on my way to HD to get the materials for the IT and a new saw blade. will post progress this evening .. thanks again!

[Lburou]

Re: The Backofen

Trellis, if you make a Hendo tool and put it in place, then lay a brick on the perimeter, the tool (or straight edge from your center point to the outside corner of the brick) will give you the angle you want with no computation at all. That works for every ring. I would query David s about his 21 inch oven and ask specifically what he recommends about brick size.

BTW, in retrospect for us, there is more fun in using the oven than building it. I would not taper my bricks again. It was a lot of effort with little return. Also, I would not attempt a tiny mortar seam on the inside of the oven (that makes it impossible to completely chink the openings between the bricks with mortar. At least one forth inch of mortar between bricks has worked fine in many a good build. Those are a couple of my observations in hindsight, I hope they are useful to you.

[deejayoh]

Re: The Backofen

Actually, now that I think about it a little - I used 5 degrees in my 39" oven - which I think was about a 1/2 inch drop per side.

But your oven is quite a bit smaller, so I think you need a sharper angle. figure out how many full width bricks you need to go around the outside perimeter, then divide the inside perimeter by the same number of bricks and you have your drop

Outside perimeter= (28 + 9) * pi = 116.2 inches, so you need 25.8 half bricks

Inside perimeter= (28") * pi = 88 inches / 25.8 bricks = 3.4 inch interior face

So if my math is right, you want to cut an angle that takes roughly 0.55 inches ((4.5" - 3.4")/2) off of each side. That's a 7 degree angle.

[Coloradoredusa]

Re: The Backofen

ok..Yah I bought heatstop 50.. 5 degree angle..ok.. I thought that was a big mortar joint when I put them next to each other!


Trellis

?Never regret. If it's good, it's wonderful. If it's bad, it's experience.?



Home Sweet Home ~ Colorado Springs!

[deejayoh]

Re: The Backofen

You should set the bricks on a 50/50 mix of damp sand and fireclay, applied with a tiling trowel so you get those furrows. That will allow you to get the bricks nice and level.

I think you said you're using Heatstop or some similar (read expensive) mortar? If so, you might want to cut those sailor bricks with a ~5 degree angle on each side so they fit together more closely. You will use a lot less mortar.

[Coloradoredusa]

Re: The Backofen

I set the floor. From what I have read you don't lay the bricks on anything .. just the insulation? I cut my first bricks today..I need to go buy another blade for the borrowed saw..will do that tomorrow A.M. The plans also say there are 3 ways you can set the first course.it also says that you dont have to cut anything on that course..correct? I am going with the sailor course..

I am open to all help.. comments etc.. from all of my fellow builders.. looking at all of your builds helps me... also with your experience..I will say thank you in advance!

Two pics of the floor and the 1st brick I cut!

[Lburou]

Re: The Backofen

Where are your pictures Trellis?

[Neil2]

Re: The Backofen

Don't depart too much from the 63% ratio. Your oven may sufferr from a loss of efficiency.

Measure the height of the oven opening on your indoor range from the bottom rack to the top opening. I think you will be surprised.

[Coloradoredusa]

Re: The Backofen

Wow.. I was thinking the same thing .. I told my friend that it seemed a little low..I think I will go a little higher, like what you said..I will post pics hopefully today.. it was just about dusk last night when i got finished.


Trellis

[deejayoh]

Re: The Backofen

I spent some time with a friend today who is very capable with his auto cad and we came up with 15"..... I think that is around the 65 % of the door height of 8.75" ..does that sound right?


Trellis

Yeah, with a 28"circumference - and a 5/8 piece of plywood under your IT - that is a pretty even radius.

8.75" might be a little low for the arch height? 15" x 63% = 9.5". I would cheat to the high end on such a small oven and go somewhere from 9.5-10", just to have more headroom to get bigger items in and out. My $0.02, FWIW.

[Coloradoredusa]

Re: The Backofen

I spent some time with a friend today who is very capable with his auto cad and we came up with 15"..... I think that is around the 65 % of the door height of 8.75" ..does that sound right?


Trellis