I want to create molds that will be used to produce cement objects.
My question is whether someone has any experience on this that he can share (what printer/technique/technology would be best, what to watch out for, etc).
From the little research I did online, my impression is that old-fashioned CNC is more suitable for producing objects short in height. And I am not sure if slicing objects in vertically-stacked layers would be of enough help to overcome this problem. And I am guessing that you have to find the initial material to carve, which would be hard for models larger than 20x20cm. Or at least harder than buying some filament and not have to deal with such things.
3D printing on the other hand seems to produce not-so-smooth surfaces, so I might have issues removing the final object from the mold. I am not sure how easy it would be to smoothen a 3D model, either by using sand-paper on it or by applying some material on top of its surface.
I have also considered resins for creating old-fashioned resin casts, but this method seems to require more skill and requires an initial prototype of the object to produce the mold from, which I am not sure I can manually produce with great precision to begin with (note here that my current models are a bit detailed, with parts that interlock between them, and not something that requires zero precision).
I am leaning more towards 3D printing now, thinking that it will be easier (given that I already have my 3D models and I could just print them), cleaner (in the sense that I won't need to create a lot of mess as with CNC and old-fashioned resin casts), and scalable to larger dimensions (since CNC, and probably old-fashioned resin casts, seem to suffer more when it comes to scaling things up). My largest model reaches up to 30cm in size and that seems like a size manageable by 3D printing.
But I am not sure what to do about:
- Smoothing the mold. Using sand-paper on a large print-surface does not seem so efficient or pleasant experience. I was thinking of trying to apply acrylic wall-paint primer on it in order to fill-in some of the non-smooth artifacts of 3D printing, but I am not sure if this will help or damage the mold instead.
- Ensuring that my mold parts fit well together to seal cement inside of them, without some kind of leakage (especially if I have to use sand-paper to re-shape the object a bit). I have no experience on how precise 3D printing is, especially when pushing the print-limits on size, as I appear to do.
- What kind of a printer I would need. My available budget is around 500 euros, give or take, so I am not sure if this can buy me a printer that can perform well in producing smooth molds, or if I would need more money. Or if 3D printers are not mature enough, to produce precise enough and smooth molds for the job.
The following YouTube video was interesting for me, but my models are more complex and often bigger in size, so if you have any extra information, it would be great:
