# How To Make a Mold



## rkapuaala (Jan 3, 2008)

I made a video on how I make molds and uploaded 2 scenes up on youtube. I didn't have a camera man, just a tripod. I also had to break it up in to 10 minute scenes for youtube. I'm going to put it here for your approval. 
Here is scene 1 and two. If they are helpful then let me know and I'll finish editing the rest of the video an upload it to youtube.


Scene 2


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## Robert (Jan 2, 2008)

"if they're helpful.." You're kidding right. Those were useless. 
Ray, I don't plan to ever do any molding but I was completely fascinated watching them. Thanks so much for posting. Really enjoyed it, super informative. 

Robert


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## Semper Vaporo (Jan 2, 2008)

Posted By Robert on 06 May 2011 11:11 AM 
"if they're helpful.." You're kidding right. Those were useless. 
Ray, I don't plan to ever do any molding but I was completely fascinated watching them. Thanks so much for posting. Really enjoyed it, super informative. 

Robert 

Oops... sorry, which parts of your reply were sarcasm?


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## alecescolme (Dec 20, 2010)

A very useful video, many thanks for posting! 

Alec.


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## Mike Reilley (Jan 2, 2008)

Great videos. I never would have thought to use wax if I were making a mold.


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## rkapuaala (Jan 3, 2008)

Apparently I need a script writer as well as a camera man; I meant to say "clay" not wax


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## Mike O (Jan 2, 2008)

I've done some basic mold making and casting for detail parts, foundations, walls, etc but have never tried two part molds or even complex one piece molds like you are doing. The processes and techniques you demonstrate in the videos are very helpful. Using heat to secure the clay base and the way you use your tools are a couple of the tips I found very useful. Please keep them coming, and thanks much for taking the time to make the video and post. 

Mike


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## rkapuaala (Jan 3, 2008)

Here's the last one on my one part molds


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## Paulus (May 31, 2008)

Very useful!!!! 
Many thanks for posting/sharing your craftsmanship!


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## tj-lee (Jan 2, 2008)

Outstanding videos! 

Thanks for sharing. 

Best, 
TJ


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## noelw (Jan 2, 2008)

Very interesting ... Looks like one needs some equipment to make them and not just out of the tool boxs. LoL. Not an every day trial and error process.. wow neat stuff. tk's for the videos.


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## Robert (Jan 2, 2008)

Posted By Robert on 06 May 2011 11:11 AM 
"if they're helpful.." You're kidding right. Those were useless. 
Ray, I don't plan to ever do any molding but I was completely fascinated watching them. Thanks so much for posting. Really enjoyed it, super informative. 

Robert 

Oops... sorry, which parts of your reply were sarcasm?


To Ray et al. Let me clarify and if necessary apologize for an confusion, hurt feelings etc. I was only cracking wise and making an attempt at wit. Ray you put and lot of effort and fantastic information into those videos. Sincerely I find they are very informative and enjoyable. 
Robert


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## rkapuaala (Jan 3, 2008)

Posted By noelw on 08 May 2011 10:01 PM 
Very interesting ... Looks like one needs some equipment to make them and not just out of the tool boxs. LoL. Not an every day trial and error process.. wow neat stuff. tk's for the videos.



Noel,
Some tools are required. Certainly not as many as I have if all you are doing is making molds for your own personal use. Its a lot cheaper than you think, and you may actually have many of the tools in your own shop.
I'll see if I can put together another video showing some of my equipment and how I modified it to suit the requirements of making molds and casting.


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## Mike Reilley (Jan 2, 2008)

This is good stuff...I'm really enjoying these videos.

The last part in Scene 3 where you get the master out of the mold...how about some more on that...it was kinda like 15 minutes on how to vacuum suck blue goo...and 5 seconds on excising the mold master from the mold. 

I recall the part about the reference line. Is there just one cut in the mold down the back of the master? Or, are there several cuts? For standing versus sitting figures, are there different strategies?


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## Jerry McColgan (Feb 8, 2008)

Very informative videos. I have at times wondered about what it would take to make figures etc. from molds.

I don't know if this is related or if it would be a different subject but how difficult would it be to copy some missing parts from plastic buildings (windows, doors etc. that have been lost over the years)? In pretty much all cases there is only one window or door missing and the buildings have other windows or doors that could be duplicated if easily possible. The parts could probably be ordered from the manufacturer but that would involve international ordering, shipping and payments over nickel and dime items.

Thanks,

Jerry


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## tj-lee (Jan 2, 2008)

> The last part in Scene 3 where you get the master out of the mold...how about some more on that.. 

What Mike said! 

Best, 
TJ


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## rkapuaala (Jan 3, 2008)

Mike, TJ, 
Mixing the RTV is actually a lot more difficult than extracting the piece. For that particular mold (Mark Twain) there were two cuts. The first down the back and the second between the legs. 
Figures with more closed in negative spaces of course will need some prior setup of a parting material, unless you want to do a two part mold. In my next series of videos, I will show the two part mold. That type of mold eliminates the need to cut your original out. 
BTW,,, been a member for about 5 years now, so I am very used to the humor,,, so no hurt feelings here


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## Mike Reilley (Jan 2, 2008)

Posted By rkapuaala on 09 May 2011 06:54 PM 
Mike, TJ, 
Mixing the RTV is actually a lot more difficult than extracting the piece. For that particular mold (Mark Twain) there were two cuts. The first down the back and the second between the legs. 
Figures with more closed in negative spaces of course will need some prior setup of a parting material, unless you want to do a two part mold. In my next series of videos, I will show the two part mold. That type of mold eliminates the need to cut your original out. 
BTW,,, been a member for about 5 years now, so I am very used to the humor,,, so no hurt feelings here  

OK...and thanks...and I mean that...so here goes....

1. I understand the cut down the back (to Mark's butt)...but cut BETWEEN the legs...versus down the back of each leg? SO...do you pull the legs/feet up and out of the mold...and that doesn't hurt the mold? This is what I meant by strategy. I've always been interested in how you get a casting OUT of the molds without breaking the casting...or tearing up the mold. In this case, Mark's feet look like they'd break off or rip up the leg part of the mold when you pulled the casting out of the mold. So...when you decide to pull the legs out...there's a strategy there that you know that tells you that you won't break the model or tear up the mold. Can you explain more about that?


2. "...closed negative spaces..." - would that be like a gap between Mark's arm and body...which I don't think your model of Mark has...but say he did. And if he did have a void between his arm and his body, I'm assuming this would be an area that needed "prior setup of a parting material". What kind of prior setup would that be...and is that setup done on the master the mold is made from...or to the mold after it's made?


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## rkapuaala (Jan 3, 2008)

Mike,,, good question, I forgot how counter intuitive the between the leg cut is. The first mold I made had a cut down the back and I noticed two things. 
1- The parting line down the back was ugly and cleaning a little harder especially on creased pants. 
2- The legs tend to get trapped when you open the mold up, making the piece more difficult to extract. 
Yes, the closed negative void example you gave is correct with the exception that Twain has none because the arms of his jacket and the front of his jacket close that void. Is arms are also held close to his body. But if a figure had its arms on its hip and was wearing a t-shirt, you definately will have a 'closed negative' space. In that situation you have 2 options: 
1- Create a two part mold 
2- apply a thin piece of paper in the void so that it comes in contact with all the surrounding surfaces. I use crepe paper. Something thin but sturdy that can easily be contoured to fit so that your edges don't have to be perfect. I fix them in place with acrylic paint, and trim the excess paper away with a razor knife.


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## rkapuaala (Jan 3, 2008)

I actually edit out a lot of what we are covering here because I needed to fit the videos in 10 minute time frames for youtube and I thought I would just bore everyone if I uploaded two hours of video. I also have a tendency to ramble, when I do this work because my mind is more on doing the job right than talking to and operating the camera.


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## tj-lee (Jan 2, 2008)

> I also have a tendency to ramble, 

Ramble away. It's all fascinating. 

Best, 
TJ


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## Mike Reilley (Jan 2, 2008)

Posted By rkapuaala on 10 May 2011 01:17 PM 
Mike,,, good question, I forgot how counter intuitive the between the leg cut is. The first mold I made had a cut down the back and I noticed two things. 
1- The parting line down the back was ugly and cleaning a little harder especially on creased pants. 
2- The legs tend to get trapped when you open the mold up, making the piece more difficult to extract....

Thanks...hadn't even thought about parting lines created by the knife cut. So...in this case...you pry the mold open and grab the torso, and pull the feet out. Is there a reason for the cut between the legs then? To me, that seems to me to present the possibility that you break the legs off at the hips when you open the mold.


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## rkapuaala (Jan 3, 2008)

Is there a reason for the cut between the legs then? To me, that seems to me to present the possibility that you break the legs off at the hips when you open the mold. 


Hummm,,,, its hard to explain, unless you do it,,, or I have some clear silicon to illustrate the point. let me put it this way, if you don't cut between the legs, you will not get your figure out of the mold. I lack the literary skills necessary to explain it, but if you try thinking about it for a few minutes and think 3D you might understand why that is.


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## Mike Reilley (Jan 2, 2008)

I got it. It was your "think in 3D" that tipped me. As you pull the figure out of the bottom half of the mold, since the legs are wider at the feet, the mold needs to "open up" as the feet move towards the "pelvic" level...otherwise, they're wedged in down below. The mold needs to be able to flex outward from the pelvis down to get the feet out. Thanks.


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## Paulus (May 31, 2008)

I thought I would just bore everyone if I uploaded two hours of video 
How did you come to that? No way! Nothing boring, just interesting! I would like to see the long version directors cut ;-) 
And _IF_ it would become boring at one point there is always the FastForward option!


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## Totalwrecker (Feb 26, 2009)

I used to cut molds for jewelry, the concept is similar. 
A good knife is a priority, I used a scapel and bought blades, #11, in bulk, non-sterilized, if the cut wasn't like butter the blade got tossed. Jewelry supply houses are a good source. 

John


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## SE18 (Feb 21, 2008)

the videos are the best mold making videos for figures I've ever seen 

Dave V


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## Mike Reilley (Jan 2, 2008)

Ditto


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## rkapuaala (Jan 3, 2008)

Thanks guys. John, the knifes pictured in the video are Stanley razor knifes with changable blades. I find that even a new sharp blade drags a little in the RTV so I put a little mineral oil to ease the cut. For my really big molds, I have an old 8 inch kitchen knife that is razor sharp and used specifically for parting molds. I strop that several times before making a cut. All the knifes I use to cut molds are used specifically for cutting molds and nothing else.


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## Totalwrecker (Feb 26, 2009)

That's ok, I only cut vulcanized rubber molds for 24 years... a tougher rubber and filled under pressure so every edge had to match perfectly, or as you know, you spend time cleaning up seam lines. I couldn't/wouldn't use any oil, too dangerous. 
My knives were job specific as well. 

You know how and I know how, but not every Joe knows how to put a fine edge on a blade, disposable scapel blades make a fine alternative... put in the solid metal handle and it looks similar to your 'long knife'. The #11 blade is a straight edge and a #12 is curved 
Scapel blades are sharper than Mr. Stanley's and flex better when needed. The edges are pre honed and ready to go as soon as you put it in. 

I wasn't being negative, just trying to share what I knew. 

I enjoyed your videos and think they will be very helpful to our friends here. 

Happy Rails, 

John


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## rkapuaala (Jan 3, 2008)

John- I didn't take it negatively. Where do you get your surgical blades? Mineral oil is ok with this stuff, I use a mixture of pertolium jelly and paint thinner for my on my two part molds to keep one side from sticking to the other and I've got molds about 6 years old that are still in great shape. Of course, I don't do the comercial runs. If I cast a 100 figures on one subject thats a lot for me.


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## Totalwrecker (Feb 26, 2009)

When I was working in the biz, we had a regular supplier. 
Today I'd google for a Discount jewelry supply, there are several. 
For me today, once a year when the Gem Show comes to town, I get a years supply. A box of a hundred or so. One blade per mold, unless very complex. 

Our rubber was pressure cooked, I liked to cut them while still warm and dusted with unscented talcum powder. Dual purpose; prevent sticking and helped provide air exits when injected with molten wax. 

John


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## rkapuaala (Jan 3, 2008)

John,,,, this was RTV? I haven't had any lucky pressurizing my RTV,,, it seems to introduce air bubbles instead of crushing them. I vacuum mine and have really clean results. 
BTW?? did you work for a foundry?


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## Totalwrecker (Feb 26, 2009)

Sorry tried to say it was a different type of rubber by describing the cure. First the rubber came in sheets 1/8" thick and I had to cut it to layer around the model, usually in sterling silver. Later we used a softer 1/4" thick silicone rubber that could be pushed into place by fingers. 
Then it would go into a vulcanizer... a big vise with hotplate faces (plattens). 

After cutting I'd inject them with wax for the lost wax casting process. There's an art form for cutting a mold and popping out a perfect copy... in the pre digital era I'd sketch a pic so I could visualise my cuts, if I were still doing it I'd take a picture, because semi-brilttle wax can distort or break earning a quick trip to the reject bin. 

Oooops too much about me.... though different rubbers, the concepts and skills are similar. 

Have a great train day. 

John


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## Totalwrecker (Feb 26, 2009)

PS I was a bench jeweler for a store in Laguna Beach Ca. Worked for the same boss for 25 years. I'm a gold and silver smith. Fabrication and casting, precious stones and inlays of stone. I could do every operation of manufacture. 

The boss would go see a new way to do something, come back and tell me what he could remember (I was lucky if he remembred half) and I figured out the rest. Was fun times. 

John


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