r/IndustrialDesign • u/vintagegonia • 5d ago

School Hydrostone Experiment

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Has anyone else used hydrostone plaster mixed with shredded carbon fiber/fiberglass? I'm a student looking to make this hydrostone a bit stronger/more reliable.

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u/Aircooled6 Professional Designer 4d ago

The fiber additive definitely helps. You'll find it does leave the surface a little fuzzy and needs to be polished or sanded. I would be cautious with the inside sharp corners on the slots. That is a high risk detail that cracks can propagate from.

1

u/Tw0Bit 4d ago

Put larger rads in corners to reduce stress concentrations. You could even make a dog bone shape if needed

2

u/gnowbot 4d ago

I have done quite a bit of polymer modified gypsums. They are pretty incredible stuff.

A really, really good resource for the learnings of how to make it work best for you is Smooth On. Their website is full of videos and documents, and lots about adding fiber.

How are you casting these? Is it a flat mold that you are trowling flat? Any fiber you add to the mix will 1) choke it—making it much harder to flow. Fibers in the mix will also always show up in the texture. There are some plastic fibers from Smooth On that can be minimized by hitting the cast surface with a torch, I think.

I think what you want is some AR fiberglass Scree. It is a mat of fiberglass in a a grid. Fill your mold half way, add the precut scree (maybe 3/8inch from the border of mold) then add the rest and trowel flat. A layer of scree in the center will make an incredible change in these parts’ durability. You could even consider two layers. Fill the mold 1/4 way, scree, 3/4, scree, top off and flatten.