/fit/ here again. I'm a thirld wolder so I want to make

>>8716706
see: >>>/diy/

Also, there are many online calculators for cement and other stuff.

>>8716706
this shit will shatter as soon as it falls from slightly too high once.

>>8716753
>dropping the barbell

>>8716882
>not using the advantages of your home gym
>do you even lift

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noo>>8716706

>>8716706
Just look up the density of the concrete you are using and divide desired weight by density to get volume.

>>8717848
At least you're not fucking up others equipment, I'll give you that.

>>8717851
Christ mate, what country do you live in? I'm guessing you're somewhere in south america since the times sync up.

>>8716882
how lightly do you think you can set down your bar when you are doing heavy deads? it'll shatter under its own weight at a point.

so if you're going to go through the trouble of making concrete weights because you don't have the money for real equipment that'll just end up breaking anyway, what is the point? just pony up and get some real shit.

buy used

>>8718845
oh and if making concrete weights are truly your best option (read: only option) then god speed and good on you for not making excuses, OP.

>look up density of concrete
>decide on a reasonable thickness
>calculate required thickness of plate
>?????
>PROFIT

>>8718903
Decide on a reasonable diameter, my bad.

why the fuck is this a thread on /sci/, fuck off

>>8718845
Seriously, if he's lifting on grass or dirt instead of other concrete he'll be fine. Or even if he puts down a sheet of plywood over the dirt, he'll be fine.

And honestly, even if he has to replace one or two plates every year, unless concrete is a fuckload more expensive than I remember, its going to still be cheaper.

Density of concrete highly depends of what kind of sand, gravel, cement and other ingredients you're using and on what proportion, there's no "the concrete" and values of density of different batches will differ significantly (depending on the material and proportions). Secondly, there's no one right size, you can make them as you want and we don't know if you want your discs to be thicker or of larger diameter, if you'll find out the density of concrete mix you're using just calculate couple different possible sizes for given volume and use one you think is best for you.
Also you don't wanna just cast them from concrete, you should add a bushing for the bar to go through, add some scrap metal bars or wires for reinforcement, maybe just throw a bunch of scrap metal to increase the weight.

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>>8716753
I've made weights just like this and they're still perfect 2 years later.

Op, if you can cast the concrete around slices of scaffolding pipe or similar for the holes it'll be stronger. like in the pic

also i painted them with a floor sealant

>>8719046
I used a standard 321 mix on the bag, strength is largely down to how long you let it go off for, i left mine covered and moistened for 2 weeks.

Just a few years ago, I was benching a cheap plastic broom with reusable grocery bags full of logs hung on either side. On my coffee table.

Had pictures of my setup, but I must have deleted them out of shame.

>>8719046
Can confirm.
We used concrete weights for our trebuchet.
Shit's cheap and durable (and heavy)

>>8719076
Omg pix

I'm building one over spring break