My first WFO design, any comments before I build?

[MarkJerling]

Good luck!

[Mark1986]

Hi Mark
You're asking a lot of those little steel brackets. The force near the hinge point, i.e. the single bolt location, is pretty big. No-one can say if they'll hold or not, but I would consider (timber) cross bracing essential if I was building it.
Regards,
Mark

I feel confident that the system won't buckle when I pour in the concrete. After this is done, I'l test if there is any movement in the frame. If so, I will add the cross bracing. Thanks for the advice!

[MarkJerling]

Thanks for the advice on safety! I postponed pouring the concrete and focused on the stand. I couldn't find cross bar easy/fast enough. So I decided to add heavy duty steel corner plating on all sides and I added additional bars 6.5 x 6.5 cm below (see photos). Is this sufficient?

cheers!

Hi Mark
You're asking a lot of those little steel brackets. The force near the hinge point, i.e. the single bolt location, is pretty big. No-one can say if they'll hold or not, but I would consider (timber) cross bracing essential if I was building it.
Regards,
Mark

[JRPizza]

Mark, I doubt if anybody here can tell you what sufficient is, since we can't "feel" how rigid your stand is and some have cautioned about using wood in the first place. That's why I used the term "overbuild" - it's so hard to know what the "minimum necessary" is, so most either overbuild or follow tried and true designs. david s said his 21" oven weighs in around 250 kilos, so at a minimum I'd find a way to proof load the stand and see if there is any wiggle or horizontal motion. If there is you need to brace better. If it feels stout under load you just need to make sure the wood does not degrade over time. Also since you are building your oven in what might be a temporary location thinking about how to pick it up and move it might be prudent, both in the case of a potential relocation or any repairs/upgrades to the stand.

[Mark1986]

Thanks for the advice on safety! I postponed pouring the concrete and focused on the stand. I couldn't find cross bar easy/fast enough. So I decided to add heavy duty steel corner plating on all sides and I added additional bars 6.5 x 6.5 cm below (see photos). Is this sufficient?

cheers!

[SableSprings]

Two points from me on your stand (as Mark, JR, & David have already noted above), ...that advised cross bracing is not just important, it's critical for everyone's safety! Also, make sure you allow your table legs to soak up the preservative from the bottom cut faces...it will soak up quite a bit. So if it's possible, dip each leg in a container with preservative & let it soak up for several minutes. Remember that you need to provide a water barrier or air gap (heavy casters) between the wood legs & the concrete floor...even with preservation, that's where the wood will decay first if it's damp/wet.

[david s]

Update


DavidS Tomorrow I'm going to pour the concrete slab. I'm thinking about wet curing it. Is this a good idea? If so, what frequency, amount of water and total days should I wet cure the slab? After how many days can I pour in the perlite concrete slab?

Thanks in advance!

Cheers

Yes, anything made with OPC will have its strength increased significantly if damp cured. The normal period is 7 days, but some do 28 days. seal the whole slab with plastic wrap.You can then make the perlite concrete (5:1) insulating slab. Because the perlcrete takes so much water in the mix it is not necessary to damp cure it. It will take a few weeks to dry, so wait around 3 weeks before building over it. Vermicrete insulating slab PDF.pdf Vermicrete insulating slab PDF.pdf

Make sure you strengthen the stand. as you've not half checked the timber it can easily move, especially if it's exposed to the weather.

[JRPizza]

To Mark's point - if you have or might have any little children around the oven consider adding the cross bracing and making the stand "overbuilt". An oven dumped on it's side would be a bummer - having it drop on a little human would be a tragedy.

[MarkJerling]

Update

So I started building the wooden frame for the pizza oven. I had quite some bad weather so I had to improvise a shelter

The hardest part for me was getting de legs and frame aligned properly. The wood wasn't perfect square and neither were the steel platings that I bought to keep everything fixed in place. Also, the first day I broke the fibre cement board, as I didn't support the cut off piece. That set me back 35 euros. Apart from that, things went quite ok!

I can't seem to upload some of the photos properly. Here is a photo of the end result: https://imgur.com/a/TqELZVK

DavidS Tomorrow I'm going to pour the concrete slab. I'm thinking about wet curing it. Is this a good idea? If so, what frequency, amount of water and total days should I wet cure the slab? After how many days can I pour in the perlite concrete slab?

Thanks in advance!

Cheers

I did warn you to cross-brace your frame. There's literally nothing stopping that design of yours from folding itself up and becoming a folding table! Sorry to be a party pooper but it's a real risk. Once you have some weight on top and a few mates leaning against it things could go South pretty quickly.

[MarkJerling]

MarkJerling I'm going for the 50/50 linseed oil turpentine mix and I'm adding wax to make it more water-resistant. Is that a good idea?

I would imagine adding a wax can work. Remember to buy boiled linseed oil rather than raw linseed oil. The turpentine acts to speed up the drying and help penetration into the wood thereby helping it become a penetrating sealer. Raw linseed oil can work but takes forever to dry, so boiled works better. Generally a 50/50 mix is good. Also remember that a pile of rags or paper towels soaked with linseed oil can actually start burning without warning, so if you have any oil soaked rags after you done, wet them with water and dispose, wet, in a bag in your garbage or burn the rags in a rubbish fire if that's allowed in your jurisdiction.

[Mark1986]

Update

So I started building the wooden frame for the pizza oven. I had quite some bad weather so I had to improvise a shelter

The hardest part for me was getting de legs and frame aligned properly. The wood wasn't perfect square and neither were the steel platings that I bought to keep everything fixed in place. Also, the first day I broke the fibre cement board, as I didn't support the cut off piece. That set me back 35 euros. Apart from that, things went quite ok!

I can't seem to upload some of the photos properly. Here is a photo of the end result: https://imgur.com/a/TqELZVK

DavidS Tomorrow I'm going to pour the concrete slab. I'm thinking about wet curing it. Is this a good idea? If so, what frequency, amount of water and total days should I wet cure the slab? After how many days can I pour in the perlite concrete slab?

Thanks in advance!

Cheers

[Mark1986]

Douglas fir (Pseudotsuga menziesii) is good framing timber but, if used outside in the weather, you'll need to treat the wood regularly to prevent eventual decay. It is, none the less, far better than pine.
Provided you protected the wood with a good penetrating sealer (or my cheap and ancient method of turpentine and linseed oil) it should last many years if regularly recoated.

Remember that an oven is a heavy thing so you need to design your timber base to be cross braced underneath or it will not be a very stable platform before long.

MarkJerling I'm going for the 50/50 linseed oil turpentine mix and I'm adding wax to make it more water-resistant. Is that a good idea?

[MarkJerling]

MarkJerling Thanks for the information! I use douglas wood, which is made from the Douglas fir https://en.wikipedia.org/wiki/Douglas_fir

Did I make an ok decision regarding the wood?

Cheers!

Douglas fir (Pseudotsuga menziesii) is good framing timber but, if used outside in the weather, you'll need to treat the wood regularly to prevent eventual decay. It is, none the less, far better than pine.
Provided you protected the wood with a good penetrating sealer (or my cheap and ancient method of turpentine and linseed oil) it should last many years if regularly recoated.

Remember that an oven is a heavy thing so you need to design your timber base to be cross braced underneath or it will not be a very stable platform before long.

[Mark1986]

It will, in large, come down to what type of wood you use and how you look after that wood. As example, I have an old jarrah (Eucalyptus marginata) telegraph pole in our garden. It will probably still be there 100 years from now.
Needs no maintenance and does not seem to rot.

But then, I have a macracarpa (Hesperocyparis macrocarpa) (also called a Monterey cypress) sign at our front gate. It is soft wood and will soon rot away if left untreated. But, even though I made that sign 18 years ago, it's still perfectly fine and all I do to it is give it a liberal coating of a 50/50 mix of mineral turpentine and boiled linseed oil, once very two years or so. It's almost black in colour now, but strucurally, it's perfectly good.

So, wood can work, provided you look after it or if it's the right type of wood.

MarkJerling Thanks for the information! I use douglas wood, which is made from the Douglas fir https://en.wikipedia.org/wiki/Douglas_fir

Did I make an ok decision regarding the wood?

Cheers!

[Mark1986]

The oven should be there for generations as there's nothing to rust away. A timber stand will deteriorate and move in the weather setting up stresses that might cause cracks in the oven and ultimate collapse from the weight it supports. If it's your only option then I guess it will have to do.

ok, that sounds reasonable! It will have to do for now, because of the choices I've made!