Oven on wheels

[metalmaster]

Re: Oven on wheels

tek screws will hold the weight, but that is only part of the problem. they will loosen up every time you put a side load on the cart and the smaller the wheel diameter the harder you will have to push to get it rolling.

[brickie in oz]

Re: Oven on wheels

I may have to go somewhere else. Too many negative waves on this forum!

Hmmm, if you only want favourable replies its probably best not to ask as sometimes the answer you seek will not be good, that goes with all forums.

There is a wealth of knowledge on this forum so take it on board and learn from it as we all have.

[wotavidone]

Re: Oven on wheels

Brickie, Its the way you do it, mate. There is a polite way, then there is your way.
You could say how big are those castors? But instead you just call it a tea trolley, without even knowing what size they are.
In anycase, I just put 203 kilos of bricks and clay on there and nothing gave. I could still move it round my carport. And yes I weighed them, not guesstimated them.
Having said that, as previously stated, I will probably take the castors off after I settle on a position to park the oven.

[brickie in oz]

Re: Oven on wheels

Maybe so, but how will it wheel?
They might be good for a tea trolley but an oven may require a bigger dia wheel to be able to move it.

Brickie, Its the way you do it, mate. There is a polite way, then there is your way.

Wow, is that all it took to upset you, I wasnt rude or anything?.
I was just straight to the point.

You could say how big are those castors? But instead you just call it a tea trolley, without even knowing what size they are.

I knew what size they were because I read it in the thread?

[wotavidone]

Re: Oven on wheels

First off, I apologise for being grumpy.
I should point out, though, I merely posted my photos of progress so far, and didn't actually ask for your advice. So your point about don't ask is not valid.

After looking at other guys builds, I decided on castors an inch bigger than they were using, exactly because I did not want too much roll resistance, and rated at 40% more than my estimated final weight (based on weighing bricks, density of adobe, etc, - I've been calculating and weighing, rather than guessing), so the comment that they might be good enough for a tea trolley, but might not be good for rolling an oven around, sort of made me feel you were questioning my intelligence. Did you say the same thing to the guys using 4 inch castors?

I've stated previously I'm optimising for pizzas, so I've settled on a moulded/poured dome about 30 inches in diameter, 2 inches thick, and two inch pavers for the floor.

We shall see how it holds up.

[shuboyje]

Re: Oven on wheels

Optimizing for pizza what's your planned dome height

[wotavidone]

Re: Oven on wheels

Low but I'll have to dig out my drawings, I can't remember the actual number. I was guided by the FB Pompeii plans. If you remember, they talk about low dome/high dome depending what you want to do most of.

[shuboyje]

Re: Oven on wheels

Just curious is all. Low dome pizza specific ovens are my "thing". I've built two of them with the first being 30". Take it for whatever you think it's worth, but I would not go much lower then 13". Guidelines you may find online like h=d/3.4 aren't meant for small ovens, and at 13" you'll have plenty of top heat for a 900F+ sub 60 second bake without having to dome the pie, which is my goal in a pizza oven.

[wotavidone]

Re: Oven on wheels

13 inches is indeed very low . I was thinking if a brick standing on its its end is 9 inches, and I used that to set the height of my door, then using the 63% ratio, the roof of the dome should be 14.3 inches. Bit worried about it all being too low though.

[shuboyje]

Re: Oven on wheels

Sounds like you have a good plan to me. For a low dome I'm a big fan of casting the entry out of castable refractory, that's how I did my new oven.

[cobblerdave]

Re: Oven on wheels

Gudday Watavidone
Hows progress? Ive been watching your posts for a while now....your in the classic Aust position of not being able to obtain the "proper" recommended forno materials. So your in the position off having to adapt what you can in the best Australia tradition.
I know a few people that have now have great working ovens who would not post thier ovens on the Forum due to the fact that there not built to the proper Forno plans or materials......so please keep up the posts...there are people who are very interested in your progress. not only myself

Regards Dave
PS check out a thread called "Tanzania /Canada" in the "pompeii oven contruction" section. Built an oven in Tanzania from some very interesting materials....

[wotavidone]

Re: Oven on wheels

Good day Dave.
I have finally made some progress, not much by most people's standards, but good by mine
I've taken a bit of a change in direction. (I apologise to a few people I got a bit short with. I don't take the most well-meant of criticism well, some days, but I am capable of taking it on board eventually.)

So here's where I'm at:

Decided the base under the floor will be scoria concrete. According to an academic paper I read, a sand cement and scoria concrete, i.e. normal concrete with the large aggregate replaced by scoria, has a W/m/K of 0.252. Not as good as vermiculite, but I've always worried about the structural integrity of vermiculite, because in my frame it had to be more than just an insulating layer with a resistance to compression. The floor of the frame is just roofing sheets over steel purlins, so the concrete floor needs some tensile strength as well.

Having made the decision to use the scoria crete, I reviewed my stand in light of the heavier floor. With scoriacrete density of around 1.6-1.8, my 90 litres of floor was going to weigh in at maybe 150 kg.
This weight would mean the finished oven would now be heavier than the screwed joints and castors were designed for.
This lead to two further decisions.
1) Welded joints (left the screws in though)
2) Fixed location, no castors, this baby is staying right here when we move.

So I bought myself one of the best tools I've ever invested in. I got on Ebay and spent $40 (with an OZ supplier, I might add) and got me a mickey mouse auto darkening welding helmet. It is simply amazing how much better I can weld when I can see what I'm doing.
The frame is now welded and I'm very happy with the outcome. Never thought I'd see the day I'd lay welds for the sheer enjoyment of it.
Poured the scoriacrete floor yesterday, with some galvanised mesh for reo.

I was a little sceptical about the scoriacrete, but when the guy (Italian descent, I think) at the gravel yard heard I wanted it to make an insulating concrete base for my pizza oven, the price became very reasonable, so I figured I'd give it a whirl. The cement, sand and scoria for this base cost me about $32. The scoria I got was quite large, as far as concrete aggregates go, probably 1 inch chunks, but I think that's actually a good thing.
I thought all the air pockets would fill with cement paste, but as the attached photos show, they didn't.

Next step is to put it in its permanent position while I can still lift it, and take the wheels off. Might put them on my Dalek.

[wotavidone]

Re: Oven on wheels

A little clip of my previous project. That one took two years to do as well. Seems like life is so full of things you have to do, that the things you do just because you want to, get left till last.

Dexter the Dalek goes to the Chrissy Pageant - YouTube

[wotavidone]

Re: Oven on wheels

Drew out a 30 inch/760mm pompeii oven on a piece of particle board last night.
I am referring a lot to the published dimensions of the FB ovens.
So I'm thinking 16 inch by 10 inch rectangular opening.
Started stacking bricks to see what the oven will look like.
I was always intending for my oven to have a square mouth, about a brick deep. i.e. 9 inches deep.
I intended to use a lintel, rather than do a curved arch.
The design of this is testing me. I have several options.
I can get an off-cut of 6 mm 316 stainless steel plate from a mate, and just lay it across the top of the side walls of the opening, with a 6 inch hole cut for my flue.
Or I have a few options with mild steel angle iron.
The thing is, I also want to use this plate as a lintel to support the front edge of the dome.
Does anyone who used a rectangular opening rather than an arch on a small oven have some close-ups of how they did it?
Also, is there a general consensus on which material is best for use against open flames - stainless or mild steel?
Which one would expand/contract the least, thus putting the least strain on bricks and mortar?
So many questions, and I still haven't finished painting the house. My employment seems to be impacting my lifestyle too much

[wotavidone]

Re: Oven on wheels

I know this has been discussed on the forum, but I can?t seem to find it.
I looked on engineering toolbox, for thermal expansion co-efficients. (Dunno what we did before that website came along.)
Anyway it says steel has a co-efficient of 13 * 10-6 m/m K.
I take this to mean for every 1 degree Centigrade that a metre of steel increases in temperature, it will expand 13 * 10-6 m, or 0.013 mm. So if you increased the temperature by 350 degrees, you?d get 4.55 mm of expansion over a metre.
I want to use a lintel about 450 mm long, so I?m looking at 2mm of lengthways expansion if I get my oven up to 350 degrees Centigrade.
I?m thinking for a lintel that is 450mm long, say 6mm thick, I can probably ignore any increase in thickness, but should allow a couple of mm of gap for lengthways expansion.
Same website seems to indicate that masonry will expand by about half as much, give or take a bit.
So I?m thinking there shouldn?t be too much drama with expanding lintels pushing masonry apart, so long as a small allowance is made for lengthways expansion.