Concrete in a saucepan problem, please help

[wavefunction]

I’m trying to make diy weight plates(all gym equipment has sold out here) by setting cement in a saucepan like so:
https://imgur.com/x8RCTLg

I left it set for over 12 hours just to be safe even though the bag says it sets in 2 hours. Still, the result is less than satisfactory:
https://imgur.com/njyymlQ

It came out in pieces and the pieces are as sturdy as an apple pie. Can anyone suggest what I did wrong please? Am I even using the right product for the purpose:
https://imgur.com/eUZw05P

Thanks,
Andre

 

[JohnD]

after 12 hours it will be stiff, but not hard. Cement-based materials harden and gain strength over time. After 48 hours they will be fairly hard. After a week they will be strong enough to handle, but after 2 weeks they will be stronger.

This is due to a chemical reaction between the cement and water. It only continues as long as the cement is wet. If you allow it to dry out it will stop and will not restart even if you try to re-wet them.

For best results, wrap your new concrete in plastic to prevent it drying out, and water it well.

Maybe try a plastic bucket next time, which has tapering sides, and a shiny, waxy surface that the concrete will not stick to. You can leave it in the bucket and pour water on top while it cures.

 

[noseall]

Can anyone suggest what I did wrong please?

What gas setting did you set the pan on? (sorry couldn't resist)

The bag bought stuff is not that good and contains an accelerant to make it set quickly. There is a trade off in fast setting stuff that means the end product wont be that good unless contained somewhere damp - like a post hole.

You would be better off with some pea gravel, some sharp sand (AKA grit/screed/concrete sand) and cement and make your own recipe. Once it has been well mixed and put into the mould, use a hammer drill or similar to agitate or vibrate the mould in order to shake all the air out.

Leave well alone with some wet sacking on top of the mould. A lining of release agent helps allow easy removal of the concrete lump.

 

[23vc]

Careful of cement burns on yer hands too, when it’s still damp.

 

[John D v2.0]

you might want to add in some reinforcement too especially if it would cause a danger if it broke during use. even a load of chicken wire would do or that mesh you get for plastering tricky surfaces

 

[Ian H]

I’d just lift the bag of concrete up and down.