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james 10-16-2007 12:12 PM

Setting guides in wet concrete
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I was thinking about the best way to give myself guides on the wet concrete slab, so I could set the SuperIsol and the oven in the right place -- and most important, to aim it in the right direction. It's easy to get the orientation of the oven floor (and therefore the oven as well) pointing off at an angle.

So, I screwed four 2" screws into the form. Two dead center of the front and back boards, and two 5 1/2" in from the back of the two side boards. I am starting the oven 4" from the back of the stand.

It really helped. No lines to wash out with the wet concrete.

nissanneill 10-17-2007 05:47 AM

Re: Setting guides in wet concrete
the concrete mix looks a little on the weak side (colour). This could be due to the colour of your sand or too little portland cement. I would prefer to have a little more portland in the mix to ensure the strength required of the base without further problems.
What mix did you use?


james 10-17-2007 08:39 AM

Re: Setting guides in wet concrete
Hey Neil,

We all use Home Depot. I have to admit that I don't know a thing about it.

What's the largest building supply chain in Australia? The UK has B&Q, where Europe is very fragmented -- Leroy Merlin (who carries our ovens), Brico and many others. The U.S. pretty much has HD and Lowe's, with Lowe's growing faster and gaining market share (their stock has outperformed HD by a lot over the past few years). You see one or the other about every 5 miles on the freeway.

When you order Ready Mix by the yard with a mixing truck, and you can specify your mix, but by the bag, you get what they make. :-)

I think it will be OK.

Ken524 10-17-2007 12:38 PM

Re: Setting guides in wet concrete

Originally Posted by nissanneill (Post 17417)
the concrete mix looks a little on the weak side (colour).

I wouldn't judge the concrete by the colour in a digital photo. Digital reproductions rarely capture or display correct colours.

In every picture I take of my project, the bricks and concrete appear a different colour or shade.

jazzfan 10-17-2007 11:59 PM

Re: Setting guides in wet concrete

Originally Posted by james (Post 17427)
Hey Neil,

What's the largest building supply chain in Australia?

It's a battle between Mitre 10 and Bunnings (I think Bunnings is winning). Used to be Nock and Kirby (Aussies might remember Joe the gadget man) - but that disappeared way back - Wonder what happened to it?


nissanneill 10-21-2007 05:53 AM

Re: Setting guides in wet concrete
Hi James,
sorry that I have been off line for a few days as the wedding is now only 6 days away and I have had so much to do on the Clubman, which is to be used as the bridal car. The deadline is getting closer and much of my time and effort is going into this at present.
The largest by far hardware supplier in SA is Bunnings, which is owned by one of Australias largest companies, Westfarmers. They do not however sell mixed concrete, only in bags. I would NEVER use these as you are liable to get anything.
We also have other large hardware outlets including Mitre 10, and Banner, but they are shrinking in numbers.
When I want some concrete, even for a few posts, I always put the trailer on and get some sand/metal mix and then add my selection of Portland in the ratio that is needed for the job, whether foundations, paths or waterproofed cement for a pool etc.
When you order readymixed, delivered in up to an 8 cubic metre semi, you specify what you need and either they will provide the mix or you can specify and they will custom mix your request.
When I put in my pool, the concrete sprayer could only get one company to mix to his formula with 1/4" gravel and extra portland and he guarenteed that the pool would be waterproof before tiling, pebble or marble sheening.
Most of the readymix is much greyer and although some digital pics may be a little off in colour, I would throw any camera away if it reproduced a neutral grey as a yellow grey or brown.
My original apprenticeship was in colour reproduction for the printing and graphic arts industry and have taught colour reproduction for 33 years and have working with digital for the past 15 years, originally on linotype and then magnascan drum scanners.


Ken524 10-21-2007 12:31 PM

Re: Setting guides in wet concrete
Hi Neill,

I didn't mean to step on your toes with the color comments. Could color variation be a result of regional materials used in the bags of mix rather than quality of the mix?

nissanneill 10-21-2007 03:23 PM

Re: Setting guides in wet concrete
Hi Ken,
No offence taken,
the colour of the sand can have an overriding effect on the colour through dominance, but our sands, (whether washed concrete - a light cream colour, brickie sand - a mid chrome yellow, and plastering sand - a red/brown) can influence the concrete appearance. Concrete for a 'strong' foundation should have a mix of around 1 cement : 2 sand : 3 gravel by volume or a slightly higher cement content.
Pictures taken inside with low light can give considerable colour casts, so flash should overcome this, even if a reduced intensity is used. The colour temperature of the flashes take out all casts. My wife has a digital camera with a Leica 10X optical zoom and large lens which often doesn't require flash fill in but can produce casts if not careful.
The pictures that James put up are obviously taken outdoors and in daylight, so no flash nor casts should be evident.


james 10-21-2007 08:26 PM

Re: Setting guides in wet concrete
I have spend much too much time in Home Depot over the years. That said, we couldn't have done either of our houses without them. I guess it's a love/hate thing.

It would be interesting to see photos of a Bunnings. Are they big box warehouse stores? Huge piles of wood, etc. ready to go. The Leroy Merlin in Florence is the closest thing Italy has to a Superstore, and it really just isn't the same thing.


RTflorida 10-21-2007 10:10 PM

Re: Setting guides in wet concrete
Sorry guys, I'm going to beat the proverbial dead horse into the ground about judging concrete from a photo, this thread is being hijacked into something FAR more than it was intended.
I have to agree with Ken. Judging concretes strength/density/composition by a photo posted on this or any forum is impossible, regardless of the camera, lighting, sand color, photo experience or masonry background.

I, like James call HD (and Lowes) my second/third homes. My work involves nearly daily visits to both, not to mention my constant "projects".

As for the concrete James has used, I know the brand very well - it is a very reliable, consistant, quality product for what it is. I have used literally 300-400 bags in recent years and only remember 2 that didn't seem to have the right mix (a little short on the aggregate). I know for a fact it will support a car or truck or room addition if reinforced properly for the application.YES, measuring and mixing the individual components will most certainly lead to a more consistant and stronger mix, but for around your home projects the ready mix bags are perfectly suited for any project. If his slab cracks, I will personally fly to CA and pour him a new one. (no I do not have any affiliation with any concrete companies - I sell tools) Nuff said.

Sorry for the rant, I just hate to see posts get taken off course or get picked to death...I really want to read and see more of James' salvage oven and any new or different ideas he may have...thanks to him and the other early oven pioneers we have a tremendous resource at our disposal.


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