Not sure where to post this.
I am wanting to take barbell weight plates (45 lb, 25 lb, etc.) and make a mold of them that I could then pour concrete into. Must be reusable.
People sell them online made of some sort of plastic. I was thinking plaster of paris.
Any ideas? Your help is much appreciated!
We made 100 lb weights using concrete for the trebuchet.
https://talk.dallasmakerspace.org/t/trebuchet-sig-2016-build-season-over/12213/107
Would love to check out the link, but it’s showing as private or non-existent. Can you double check it for me?
Also as a side note, I’m looking to make a weight plate that looks comparable to a metal one, not necessarily just a functional circle.
You need to have your “Member Access” green dot - go to the “Member Access (Green Dot)” and request your green dot [assuming you’re a member of DMS].
I let my membership expire about a year ago because I wasn’t making it into the space enough…
That thread was all about casting concrete into something analogous to weightlifting plates in pure function with no regards for aesthetics, so not relevant to your request.
Was interesting to go down memory lane however.
Got a link for one of this style?
I can think of a few ways, but must be reusable and how many times and does the weight matter or just the appearance… all questions rattling around, along with why. I mean, if they’re already sold online in plastic, what are we trying to accomplish that buying those does not? Cheaper? Reusable more times? Just the thrill of DIYing it? 
Oh yeah, forgot to mention, 1 is $115. Here’s the link:
I would want to be able to pour multiple at a time and I don’t want to spend the hundreds it would take to buy the molds I would want. And yes reusable at least a few times would be great enough if easy enough a process to make the mold.
Yes, weight matters. Only the bottom impression is cast and then it’s a smooth cylinder up from there. It’s pretty easy to get very close to the desired weight.
Vacuform molds…
Wooden master will last a looong time. Can make many additional molds.
That appears very doable on first inspection
won’t get the depth on that commercial unit (I think that’s more like 18" deep, but I could be waaay off) but 11" should be plenty for most tasks, I’d think.
Mold only needs to be a little over 3” deep. Should v work fine
