39" Oven in AZ

[deejayoh]

Re: 39" Oven in AZ

I got curious and loaded your first pic into powerpoint so I could measure that angle - which looks to be ~8.5 degrees - which seems to me to be right for where you are in the dome.

The other thing I noticed is that your IT is laying on the brick in that picture and it appears to me that the brick should be tilted at least a bit more to align with it. You need to get about 7 degrees more arc with every course, or you're not on track. Try taking a bunch of bricks and stacking them just to see how the dome will look. I don't think you are in any danger of getting ahead.

[Grtiz]

Re: 39" Oven in AZ

Dennis,

I'm convinced I must have imputed some bogus data into the spread sheet. If I stick with a dome that follows the IT and doesn't end up slightly flattened the measurement is 11.8 degree on tilt and 5.5 on the angle.

The wedge course on the top of the sailors was done so that the 1st course would not require a wedge and it would match the IT.

While I am still a bit lost here it would seem that by providing this wedge course that holds to the angle dictated by the IT I would have a limited requirement for wedges as I moved up the dome.

I did end up making a new IT with the turnbuckle so that I could pull in the dome to flatten it out however I think that would mean I would have to depart from the guidance of your spreadsheet. I'm not sure I'm ready to take the training wheels off. Particularly after I started cutting the bricks on the inner arch.

Just for grins what are your thoughts if I stayed with the wide side narrow side pattern at least for this 1st course? It does seem to be follow the IT very well and would require little mortar.

[Grtiz]

Re: 39" Oven in AZ

I got curious and loaded your first pic into powerpoint so I could measure that angle - which looks to be ~8.5 degrees - which seems to me to be right for where you are in the dome.

The other thing I noticed is that your IT is laying on the brick in that picture and it appears to me that the brick should be tilted at least a bit more to align with it. You need to get about 7 degrees more arc with every course, or you're not on track. Try taking a bunch of bricks and stacking them just to see how the dome will look. I don't think you are in any danger of getting ahead.

I'll stack some bricks up this afternoon and take a look and snap some more photos to get a better diagnostic on the issue.

[mrchipster]

Re: 39" Oven in AZ

Chip, so narrow side down? I ended up with a calc of 11.8 on the tilt for this course. I must have screwed up something in the calculator.

Not sure what you are saying here? The bottom of the bricks should be wider than the top both at the inside of the oven and the outside.

From narrowest to widest it is as follows

Top inside
Bottom inside
Top outside
Bottom outside.

In rare cases the two middle widths may reverse position in width order, but the top of the brick should always be narrower than it's related bottom.

[Grtiz]

Re: 39" Oven in AZ

OK here is the spread of the photos today. Even wedged with another 5 degrees on top on wedge course over the sailors there seems to still be a massive V.

However if I went wide side narrow side and start wedging the bricks above it I seem to be back on track. Mind you I have only cut those two bricks with the 11.8 degree tilt along with the 5.5 degree side angle. So it isn't to late to change that.

I'm going to have to find Kens thread that demonstrates the inverted V because I'm failing to see how I can achieve an upside down V.

I tried a dry run up 6 more courses with the IT and shortened the IT as I went up and it seemed to work fairly well with the turnbuckle. But then I'll be on my own with the tilt and side angle

[deejayoh]

Re: 39" Oven in AZ

All I can guess is that the bricks went through the saw at a steeper than 12 degree angle. The only other possibility is that the angle of the bricks isn't way less than 12 degrees - but it looks to be that.

The twist and tilt method is pretty foolproof. Set up a jig on the bottom of the brick that is the same angle as your brick course. Set another angle on the side to give you the amount of side cut you need. Run the brick through, and when you put them all on the ring they fit together.

So for the cut to be so severe, I think the bottom angle was too steep

http://www.fornobravo.com/forum/f28/...tilt-2802.html

[Grtiz]

Re: 39" Oven in AZ

OK so I'm back from an extended trip and I reviewed the hell out of what I done. The "wedge" course is at 15 degrees which is 3 more than than the 12 I cut already and that came out exaggerated. I have triple checked the jig I made and it was at 12 degrees.

Following Hendos method I should have made the tilt at 15 degrees which would have exaggerated the V even further. I am clearly not seeing something that must be right in front of me.

The jig I made is a replica of the one that Utahbeehiver made.

[deejayoh]

Re: 39" Oven in AZ

AHA! I finally see the problem. Russell's jig doesn't use the same approach /measurements as Hendo's does.

Hendo's approach - the brick is shimmed at the back @ the same angle of the dome course, and from the side @ 5 or so degrees, giving the right compound cut

Russell's jig tilts the brick from the side, not from the back


Seems to me that both approaches can give the same final result, but the settings for the tilt will be different and I was thinking of Hendo's approach when I buillt my spreadsheet. You must be applying 12 degrees to the side tilt using the Beehive Jig and that is WAY too steep.

I will need to do some figgerin' to translate. Let me look into it..

[mrchipster]

Re: 39" Oven in AZ

I used the spreadsheet calculator by JCG31 and the work done in the "Its time to go vertical" thread.

My jig is similar the Russell's, read the following post and you should be able to follow it.

http://www.fornobravo.com/forum/f28/...ble-16780.html

[deejayoh]

Re: 39" Oven in AZ

Thanks Chip! that does seem to be the translator. My spreadsheet uses the figure on the horizontal axis. Grtiz needs to use the figure on the vertical axis.

I will see if I can track down the original spreadsheet from JCG31 and marry the two.

[Grtiz]

Re: 39" Oven in AZ

You two rock! I am looking forward to getting back on track!

[Grtiz]

Re: 39" Oven in AZ

OK. While beating my head against the oven while trying to figure where I had gone wrong with the Inverted V angles I could not resist doing the arch. I'm not super happy with how it came out but I'm sure I could have done worse.

This morning I went out to start some cutting and I noticed a crack in the wedge near the keystone. Is this a fatal flaw?

[mrchipster]

Re: 39" Oven in AZ

Not perfect but not bad, I think you will be very happy you chose that type of arch. It will make your transition to the dome quite easy. Remember to start your courses at the arch, cutting the bricks next to the arch first, creating those odd shaped bricks last will cause more headaches, if you need to get both sides of those bricks perfect by creating them last.

Transition to an ideal brick over the next 1 - 3 bricks and you will be golden, no one but you will ever see the area right next to the inner arch. Unless you show us photos of course.

[UtahBeehiver]

Re: 39" Oven in AZ

Mr Chip and Dj,

Glad you are helping Mr. G. Must of miss the latest postings. With my jig I did use the JCG31 spreadsheet data as a baseline with my bevels and angles vs Hendo's approach. Mr. G, whether it is DJ's or JCG31's data, the numbers get you in the ball park. Each build is slightly different and so a little adjusting is always in the stars. Good luck.

[Grtiz]

Re: 39" Oven in AZ

Is there actually a spreadsheet that JCG31 put out with his chart?

I started a jig like hendos as I'm still unsure how to correctly incorporate your jig into the method.

patrick