Experimental Norse-Kiwi Hybrid Oven!

[cobblerdave]

Re: Experimental Norse-Kiwi Hybrid Oven!

G'day
I don't think that paints a problem a wire brush and a bit of elbow grease, even if you burn it off its nor as poisonous as the zinc and it will be gone in the first fire.
Has the stove still got a top and chimney hole. Or was the chimney on the back?
Sorry if I frustrating you I just can't seem to get a visual picture in my mind.
Remember though it is important that the oven opening is. 63 per cent ( or near enough to under. 2/3 of the interior height of the oven ) that way it will breath regardless of the posh oven frontage.
Regards dave

[Toomulla]

Re: Experimental Norse-Kiwi Hybrid Oven!

I have read the on going discussion on zinc fumes and was not convinced that the facts support the discussion.

The problem of zinc fumes applies to welding and the high temps zinc boils at about 2300 C our WFO get to about 550 C so I do not see the science

[UtahBeehiver]

Re: Experimental Norse-Kiwi Hybrid Oven!

I have tendency to agree with Toomulla, I am in charge of welding fabrication shop and yes welding on galvanize metal is an issue. We either use source extraction or respirators to protect the welders from the "fumes" coming off of molten zinc. But, like Toom said our ovens will never reach molten zinc temps and if they do we have other problems. That said, it never hurts to take precautions if you so choose, building an oven exposes us to various substances that may or could be bad for us, ie silica, quartz, ceramic fibers, cement, etc. So I guess you err on the side of caution as you see fit. My 2 cents.

[cobblerdave]

Re: Experimental Norse-Kiwi Hybrid Oven!

G'day
Zinc melts at 416C. Zinc plating is carried out at 460C. That's in the range of the WFO. As for fumes, zinc is no different than anything else it will give of fumes from a liquid state.
The crazy thing is our bodies need a certain amount of zinc . You can buy zinc supplements! But to much is still a bad thing.
I'd definitely follow the advice that zinc plated items are only designed for applications under 200C
Regards Dave

[Toomulla]

Re: Experimental Norse-Kiwi Hybrid Oven!

I agree Dave if you think it will melt and drip or flake off don't use it it is reference to its toxity or poisonous properties that need debunking if we have a reason not to use lets distribute the correct reason

[Gulf]

Re: Experimental Norse-Kiwi Hybrid Oven!

There is also, the option of "torching" the galvanzed metal, before it is intalled .

[Wildflower]

Re: Experimental Norse-Kiwi Hybrid Oven!

Thanks everyone for your advice on the zinc toxicity caper.
I plan to steer clear of it, but have used my galv angle iron as a proxy to see how the set-up could work for the "inner arch" area...see photos attached. I somehow have to get the brick work to meet up with the cast-iron top and chimney outlet, hmmm...any ideas??? Is it ok to have the angle-iron where it is - right up against the arch of the main part of the oven, or should I try and make a sort of throat, so that the smoke comes down at an angle and then up through the chimney? There is about 80mm from the edge of the arch to the edge of the chimney outlet, so I could do something in that space.
It's not plain sailing, but from what I've seen on this forum, this part of the oven build often isn't straight-forward!
See also I've found an old damper, which I intend to have to use for when the oven is in bake mode.
Another question...do you think I should insulate the whole thing, including the Jotul stove top, or leave that so I can access the top of the stove (hehe, in case something goes wrong there - of course that won't happen. maybe.)

[cobblerdave]

Re: Experimental Norse-Kiwi Hybrid Oven!

G'day
Sorry just been a bit busy to have the time to bring you pics up on the computer so l can look them over at a decent size.
What I can see so far that brick vent seems to be a reasonable size to funnel the smoke into you steel chimney.
Sorry to revisit the zinc again. But from the pics it doesn't look that angle is gal dipped? Hard to tell from pics but it never hurts to ask someone for a secound opinion from someone local with knowledge of such things
Regards dave

[david s]

Re: Experimental Norse-Kiwi Hybrid Oven!

Galvanized coating on the steel definitely disappears if you fire it in a WFO so it has to go somewhere. Zinc may not behave like lead, but lead is considered toxic when it melts and this is what has driven the development of lead free solder. I'd be keeping any zinc out of a chamber that you are also putting food into, but you gotta die of something, zinc might be better than a broken heart.

The Hazards of Solder Fumes - Sentry Air Systems

[Wildflower]

Re: Experimental Norse-Kiwi Hybrid Oven!

Don't worry, there won't be any zinc/glav iron in my oven. Although I could die of a broken heart if the bloody thing falls to pieces on the first firing!

Are there any suggestions for an alternative to using angle iron in my situation? Or is angle iron the way to go?

Also, how long should I wait before I dare to remove the form below the vault?

Thanks again, it's so great to have the help of everyone on this forum!

[cobblerdave]

Re: Experimental Norse-Kiwi Hybrid Oven!

G'day wildflower
Be patient with removing those forms. Leave it a week, 2weeks if you able and then still be careful in removing them
I'm sure you oven will work well into the future
Regards dave

[Wildflower]

Re: Experimental Norse-Kiwi Hybrid Oven!

Hey Dave, Argh! I was too impatient even to wait for a reply...removed the form just now....and it didn't collapse!
Time to crack open the champagne.

[david s]

Re: Experimental Norse-Kiwi Hybrid Oven!

In kiln building the end walls should be under the vault rather than sitting beside it because when the vault expands it tends to push the end walls out. This is not so much a problem for an oven because the temp rise (and therefore expansion) is only about half that of a kiln, but you might consider it when constructing the end wall for the front.

[cobblerdave]

Re: Experimental Norse-Kiwi Hybrid Oven!

G'day wildflower
Could help yourself could you ! Well I was being cautious on your behalf but that mortar will not be cured for a will so be careful for a few weeks .
I think you been paid a compliment. Davids has not noticed the back end wall is under the arch roof , so your works passed his eye. Great you took the time to stagger the bricks as well.
The brick work I've seen to get the smoke to funnel to the chimney looks pretty good from here. You plan to ceramic blanket the steel of you entrance seems to be a good plan as it will give you an expansion point between the steel and the render.
Can't think of much more except that you had better start to fill those
gapes between the bricks with some mortar sometime soon.
Regards dave

[Wildflower]

Re: Experimental Norse-Kiwi Hybrid Oven!

No, couldn't help myself! Heehee. I was having difficulty trying to visualise the oven opening with that pesky formwork in the way too...man, this is a bit of a brain drain! I've now read about welsh arches, using three bricks to span a space...I wonder if this would be better than using angle iron?

I was wondering about Davids's comment - he can't really have thought that the back wall wasn't under the arch, could he?

Do you mean fill in the gaps between the bricks on the inside of the vault?

The toughest thing is going to be keeping the kids off the vault before the mortar hardens!