Meta-Molds - molds that make molds.

Meta-molds, or molds that make molds sound like they'd speed up RepRap's repate even more.

While I know that usually we make the mold from the original piece, I think it might be interesting to design a set of pieces that you:

Making the meta-mold
1) print out plastic parts.
2) assemble into meta mold with bolts-n-thumbscrews, rubber bands, dowel-pins, etc.
3) Pour plaster into meta mold.
...
Now you pop out your plaster piece.

Making the mold
1) Assemble the plaster parts into a simple mold.
2) Pour your resin, polymer concrete, etc. into the mold.

Done!

---

It's a simple idea that means taking a little more time, but all of a sudden you have 5000 plaster molds, you pour, you demold, you repeat.

---

I will not suggest super-meta molds, as that's just silly.

Good idea. There's an acrylic modified plaster that's used for body molds and architectural work called Forton MG (modified gypsum). It's stronger, lighter (cheaper freight costs) and holds finer detail than common ol' plaster of paris, not very much more expensive (the cost difference could be saved in post or shipping costs), and it's waterproof. Gauze fabric reinforcement can make a shell mold practical that's a stretch for plaster. Because it's not porous like plaster, it's surface retains release agents like PVA or silicone more reliably.

Would it be possible to get your Reprap to print a negative of a part to be used as a mold? You could pour the pieces in the negative minus all the holes, which could easily be drilled out after the fact.

Would it be possible to get your Reprap to print a negative of a part to be used as a mold? You could pour the pieces in the negative minus all the holes, which could easily be drilled out after the fact.

In general, yes. In practice, it depends on the geometry of the part. If it is a large brick shape, that is easy.

I am ashamed to admit I have not done a careful analysis of each mendel part to see how to make them with molds, or if even if a given part can be made simply with a mold. I need to.

But that is one of the primary reasons why I created this forum. I also need to do a survey of all the files, photos, and so on of previous work in Mendel Molds and do up 2 wiki pages:

Printed Mendel Molds
and
Poured Mendel Molds

There's been a lot of work by people on this, but they don't realize that in doing RepRap development, they're actually defacto RepRap developers, and they should create new wiki pages for us on stuff like this.

There's an acrylic modified plaster that's used for body molds and architectural work called Forton MG.
I've made a note to look into it. Thank you. I know about the modified plaster "Hydrocal" but I haven't thought to look int

---

-Sebastien, RepRap.org library gnome.

---

Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything!

I'm in the process of a detailed survey of the Mendel parts right now. The molding process is actually more interesting than the printer for me at the moment. But that's because there are so many haters on this site of pouring technology, I feel like I have to implement it just to poke them in the eye. I upgraded Dr. Bowyer's original pouring plans to use a new kind of Urethane Plastic that's available that cures to 80D Shore instead of 72D Shore like his original version. I don't think it's available in Europe unfortunately. But to your comment, there isn't a piece that isn't easily molded. But there are a lot of duplicate pieces that can be combined into a single piece for the purposes of pouring to decrease the necessary molds. I've also been testing using Basal Wood and Styrofoam as the original piece to allow people to generate their Mendel parts for themselves. Both turned out even better than I imagined possible. But given the nature of the whiners that hate pouring I figured I better finish everything and have a functioning unit before I brought it up or I'd hear no end of tripe.