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How to 3D Print Molds for Small Batch Concrete Casting

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Recently I took my first step into the exciting world of 3d printing. The result? I learned how to utilize basic CAD modeling and a 3d printer to create quick and precise custom molds for small batch concrete casting.
 
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Step 1: Overview

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About a month ago I visited the Annex (Instructables' old shop location in SF) to chat with shop guru Steve about what people had been making with the Objet Connex 500 3d printers. Steve showed me gadgets made with multiple materials and moving parts, crystal clear resins, a small model ship that had broken from insufficient wall thickness, and a super duper detailed character design created by somebody in the movie business. Steve explained how the resins, packaged in what looked like giant sized "ink cartridges" could be combined to create unique material characteristics (rigid, flexible, translucent, clear). He also walked me through the cleaning process, a necessary step where support material from the initial print must be removed with a combination of hand tools and pressure washing. I was surprised to find that both the support material and even the final cured resins were fairly toxic. After picking up a few 3d printed Instructables robots I was advised to wash my hands thoroughly. I also noticed that the general feel of the cured resins was somehow 'off' from the consumer plastics I was used to touching on a regular basis. 

Fast forward one month later to Instructables' new diggs at Pier 9 nearing completion and the last two weeks of my Artist in Residency quickly closing in. I had the green light from NoahW to get creative with the newly relocated armada of Objet Connex 3d printers. I was excited to finally use these crazy machines, but still wasn't sure how I would approach the material issues that I had learned about during my visit with Steve. 

I love making things that are seen and touched on a regular basis; useful things inspired by everyday life. With the toxicity and visceral quality of 3d printed materials hindering my thought process, I spoke to Randofo (friendly and helpful featured author at Instructables) about utilizing the good characteristics of 3d printing while avoiding the bad ones. He suggested I create molds. What a great idea! Making molds would allow me utilize the precision of CAD software and 3d printing while fabricating the final product(s) in a secondary material. I immediately recalled my recent desire to make small scale concrete castings...



*Photo credit: audreyobscura
fingers5711 months ago
Where can we get to use these wonderful machines. you are very lucky in the USA. I don't think we have anything likr this in the UK. Don't I wish. Please tell me if you knoe diferant I live in Leeds Westyorkshire. Gods Wonderful County
_soapy_ fingers5710 months ago
fingers57: http://leeds.hackspace.org.uk/ is your local hackspace.

There are a few hackerspaces near you, including the UK's biggest one in Nottingham, called NottingHack. It is actually their open day today!
diyluke11 months ago
If only I had access to a 3d printer (As well as access to your CAD files)
nthomas1211 months ago
I love instructables, but my only criticism of projects like this is: why is the computer needed? Why can't you just measure and cut this form out of a piece of wood using basic woodshop tools, then make a mold of the wood block? It would be simpler for the general population who doesn't have access to digital 3D modeling.

Don't get me wrong, I'd love to have access to all the latest technology... just I could make this (and I teach students these processes) using a couple scraps of wood, a tablesaw, bandsaw, maybe a sander and it would take 20 minutes.

Keep up the nice instructables. Just my 2 cents, and believe me, it's not really meant to critique what you've made here, just I guess coming from my Luddite background and tendencies!! :)
Mex5150 nthomas1211 months ago
I understand what you are saying nthomas12 but think about it the other way around, I own a computer (we several, but that's another story LOL), off the top of my head I can think of two people with 3D printers, but nobody with a bandsaw. I have no doubt if I asked around, the number of people with either/both would dramatically increase, but the point is you are guilty of what you are complaining about, other peoples chosen tools may not be the same as yours. Even if I owned both a bandsaw, and a 3D printer the bandsaw would go practically unused because I'm much more familiar with the 3D printing technology.

I'm not spoiling for a fight, just saying horses for courses, doubly so with this instructable, as it would be next to impossible to from the finished cast object if the mold used to make it was printed, or made from bits of wood that were knocking about.
nthomas12 Mex515011 months ago
And I know that 3D printing and digital technology are the way of the future, and I would love to learn these tools, so I really didn't mean to critique this project. It's actually really inspiring. I guess I just found Instructables through looking for simple DIY projects, and I've been surprised by how high tech many of the entries are.
It would be very nice if you could make a video and post it on YouTube of how you make the same things without a 3-D Printer. I,m sure there are a lot of people out there (like me) who can't afford a 3-D Printer ,though i would love to have one,that would be very interested in doing these things without high-tech expensive tools.Then again ,i probably couldn't afford a bandsaw or sander.
Actually, I have been thinking for a while about how to incorporate making an instructable into my 3D Design class, and I think this is the perfect kind of project for doing this. I'll try doing it next semester.
I've been looking for a good new mold-making project to teach that isn't as time consuming as the one I've been doing in recent years, so this looks like a good direction to go!!
So, I guess I should apologize if my rant was at all negative in tone, I should just say that I found this Instructable inspiring and leave it at that, even if I would use different methods to achieve the same outcome.
That's fair enough. I don't have any woodshop tools but I know what I'll be printing this weekend!

Awesome instructable, thanx! :)
THEFORREAL11 months ago
This is very cool. I was thinking it is possible to make 3-D Printed molds for just about anything. Spare parts,Coffee Mugs etc. 3-D printed knives? I would like to make molds to make my own bullets and perhaps i should have asked this question on the 3-D Printed gun website. I'm a good-guy..Trust me. I would like to say a very special thanks to all those who post these excellent instructional How - to pages and videos on Instructables and elsewhere and for sharing these great ideas.even the smallest of Instructables could mean a lot to someone out there including those who aren't very skilled like me. I Would like to see more on YouTube also.
woodNfish11 months ago
Ricardo Furioso: One common term is computer aided manufaturing or CAM, but that leaves out the CAD (computer aided design) part. Some people us CAD/CAM or "desktop manufacturing". But it began 20 years ago as a method to do fast prototyping and some macines even do metal sintering to produce metal parts. Anyway, this is not a new technology and the cost of the machines has dropped dramatically.

fingers57: I guarantee you have this in the UK and all over the world. It is not new and more in-house and independent design houses are buying these machines as the cost drops because getting your product to market faster than your competition means more income and more market share.
woodNfish11 months ago
I am unable to use the "reply" button for this comment, but it is in reference to nthomas12's comment. I agree with him, this instructable could have been done using more common methods and affordable everyday tools like blue foam and hot glue, or even blue foam and carpet tape. Even so it is a creative use of concrete and I like the designs.

agooodname11 months ago
now if only i had a 3d printer
Oldbear11 months ago
I'm inspired to go home and make something out of concrete...
Language is so slow and technology is so fast.
We call it "printing," but it's really not.
We're sort of in the same place as automobiles
when they were called "horseless carriages."
So.
We need a better word for this three-dimensional deposition process.
Actually.
We need at least four BRAND NEW new words.
I have a some not-so-obvious questions:
1. The (printer) machine is a __________________________?
2. The (ink) stuff that goes into the machine is _________________________?
3. The (printed) stuff that comes out of the machine is_____________________?
4. The whole (printing) process is called____________________________?
This matters.
Because the language we use directs and controls our thinking.
And this is WAY bigger than printing.
czarnian11 months ago
for better results in the casting process, try vibrating the moulds once poured the slurm in there. dunno, anything that can vibrate, maybe a vibrating surface, an ongoing washing machine, anything that can produce vibration to the compound making the trapped air bobbles go up and away. This vibrating motion results in better solid settlement, it liquifyes a bit the concrete soup so it will release some more water out of the slurm, making the contrete less brittle and more solid and compact. Good instructable.
JoeMurphy11 months ago
Will you post the stl's?
JoeMurphy11 months ago
beautiful work. beautiful instructable.
timwikander (author)  JoeMurphy11 months ago
Thank you Joe!
CHENG Concrete11 months ago
Really nice process in all of your instructables! I didn't know a 3d print could be made flexible enough to be used as a mould like that. thanks for sharing.
timwikander (author)  CHENG Concrete11 months ago
Thank you! Your instructables partly inspired this project!
M.C. Langer11 months ago
Awesome job, Tim!!!!
timwikander (author)  M.C. Langer11 months ago
Thanks Mario!
GorillazMiko11 months ago
Thank you for linking Super Duper Burgers in your Instructable.
timwikander (author)  GorillazMiko11 months ago
Haha I knew someone would appreciate that.
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