Plymouth Pompeii Build

[nicolly13080]

Guys Im a good way through my 38" build in Plymouth.

I have overcome the frustration of working out the arch transition and have also got over "everything must be perfect".

having said that, I have taken several chains off recently as the dome was looking a bit conical!

next question really is, anyone use a terracotta chimney pot as a chimney flue or will the heat be too high and crack the pot?

I've attached some images of the build so far, as you can see I taken things down and rebuilt things several times!

Olly :-)

[oblertone]

Looking good; I see you're using wedges rather than the IT route so once your happy with a completed ring put in a false floor and form a sand mound, then lay your bricks to the mound. That way you can determine the finished height of your dome relative to your archway before laying any brick. I'm sure you are aware that the optimum arch is 63% of the inner dome height, you've got the arch height set so just pile sand until you reach dome nirvana.

As to the terracotta pipe, I've not tried it myself but all the reports I've seen indicate cracking at the lower end where flue temperatures easily reach 500c.

[nicolly13080]

Thanks for the advice I've worked out that my arch is 63% of the internal diameter height so im good with that one. However, I have made a mistake in my calculations with the first couple of chains which has caused the form of the dome to go airy.

I am thinking about taking the bricks off, cleaning them up and starting again, but this time using the IT method or making a polystyrene former.

Hey ho, you learn from your mistakes it will only set me back a little bit.

[nicolly13080]

[nicolly13080]

Have finally finished the oven, got ceramic blanket on vermiculite concrete insulation and then finally this weekend scratch coat and then final waterproof top coat. I am really chuffed with the end result. I managed to get hold of an old cannon top terracotta chimney pot which I then lined with a 6" stove pipe, I had some vermiculite left over so filled the void between the pipe and the chimney with insulating concrete. Seems to have worked pretty well. The pot was cracked already so I'm.sure it will provide an expansion joint if it get too hot. Fired the oven up last night for 2 hours with really vigorous fire and outside of chimney only reached 65oC when flue gas temp was 350oC plus.

[spider44]

Your oven is looking great. I really like the chimney pot idea and using a liner looks like a good idea. How many fires did you have before getting it up to full heat? I've had 4 small fires and the dome appears pretty dry and felt warm last time (no insulation as yet) after the fire.

[nicolly13080]

I did about 4 or 5 fires ranging from small kindling fires to full on vigorous full temp fires. Tbh I am pretty impatient and prob should have done more smaller fires, but one post I read said that the oven will dictate when its ready and it was quite right. I couldn't get a really decent fire to establish properly until the moisture had been properly driven out. If you have already had a few smaller fires I suggest you give it ago with a gradually larger one. I've been burning ash logs in mine (I have a free unlimited supply) which requires a fairly vigorous fire to get going, I would say dont be scared, it's not going to fall down at this stage. I've had quite a few 2-3 hour full temp fires in mine and have not had to re-point the inside at all. Once you have a larger fire established you will see steam start to make its way out and the outside of the oven will develop lots of hairline cracks (don't panic) at this point really make sure you move you fire around the oven so that all of the dome gets a good amount of heat. Also make sure you cover the dome once coll to the touch, you don't want the weather to undo your hard work. Also its is vitally important and no-one tells you this. You must, must, must have a good supply or beer or wine when firing!!! Well done and enjoy. :-)