Step 4: Making the Molds - Body

Most of the molding and casting materials I used for this came from Reynolds Advanced Materials.
They are a great resource with a ton of great information on how to use their products.  I spent a ton of time on there website going through all of the different materials and learning as much as I could.  I was also fortunate enough to have one of their brick and mortar stores right here in town where I live.  Their staff was also really helpful in helping me with any remaining questions I had.

Due to the size that these molds will need to be, I'll be using the hard shell mold technique.  This technique consists of an inner silicone liner covered with a hard exterior shell to help it maintain the proper shape.  There are a bunch of resources online for different techniques, if you interested in casting and mold making you should definitely check them out. I decided to go with Smooth-On Rebound 25 rubber for the molds with a Plasti-Paste shell.  Both of these are available at Reynolds in smaller trial sizes as well as a 1 gallon size. 

Since this mold will be split into two pieces, the first step was to create the division line for the first half of the mold. It actually worked out really nicely that a piece of foam core perfectly fits into the center groove of the body that exists as part of the design.  After adding some registration keys, you can use anything really, I used acorn nuts, and a clay dam around the perimeter, its time for rubber.  The clay damn will stop the rubber from just running right off the side of the foam core.

The silicone comes in two parts that you mix equal volumes of to activate.  It was applied in layers to build up the proper thickness.  A thin initial coat was applied over the whole surface to make sure there weren't any air bubbles in the mold.  After this coat started to set, I applied a thicker second coat.  After this coat started to set I added in registration keys for the hard shell mold.  This will ensure that the rubber always fits properly into the hard shell and that there isn't any distortion of the shape.  For the third and final coat of silicone, I added a few drops of Thi-Vex II silicone thickener to thicken up the rubber allowing me to apply a thicker coat.  The thickener stops the rubber from flowing down and settling in the low spots. 
After the rubber had fully cured which takes about 6 hours,  The next step was to apply the hard shell.  The first thing to do was to move the clay damn out about 1 inch to make room for a hard shell rim.  The Plasti-Paste works similarly to the rubber.  It comes in two parts that need to be mixed together.  The Plasti-Paste is applied in a single step.  There is no need to do layers like the silicone.  After a few hours this is fully cured.

Time to do the other half of the mold.  After removing the foam core, the second half is pretty much the same as the first so I'm not going to bother repeating the steps.  Once the two half were made, The last thing I did was to drill holes around the edge.  There are for bolts to close up the mold and make it easier to cast pieces.

Materials used for this stage
Foam core
acorn nuts
oil based clay
Smooth-on Rebound 25 silicone rubber
Thi-Vex II silicone thickener
Smooth-on Plati-Paste
Mold release agent
<p>This is so impressive, I really love it!</p>
<p>Here I resized a version of the blueprint to print actualy size of the turret and increased the quality it isn't prefect but it pretty close to the original</p>
<p>Photoshop it Into place Thats what i used</p>
<p>So, Would this be good for a Portal/Halo/Tf2/Borderlands/Half-Life Nerf war? Were having some debate over which Turret we should use. A tf2, or a Portal. So, Is it easy? And how long will it take to make?</p>
<p>valve didnt actually make it, it was a gift to them</p>
<p>Did anyone know that Valve has something like this at their HQ?</p><p>No, not robots straight up murdering people. </p><p>Valve isn't that evil. </p>
<p>and the Sentry from TF2.</p>
Hello, is it possible to have access to the blueprints your friend did for you? I don't have tyler garrison as a friend... ? and i want to build a turret.
is it going to shoot me <br><br><br>( no hard feelings)
It just might so watch out.
<p>Wow,super...Great job!</p>
<p>Does anybody have a estimated Cost/Hours for this? I really don't wanna start this and run out of money halfway through or not have the time to finish the build. </p>
<p>I would like that but just to make it sound more deadly... For Example went it said target acquired just in a deeper voice and no singing. Make it sound like it's a treat. Other than that it is pretty interesting.</p>
<p>so cool honestly.</p>
Willing to pay $60 for a pre made one without electronics
How much wold this cost to build????
Would it work to skip the molding process? (I am on a low budget and the molding stuffs is pretty expensive)
How much for a pre made one, BTW you NEED t check this out: http://www.egmnow.com/digitalnoob/valve-receives-its-own-portal-turret/
molds please please please please I really want da molds
give me those molds peas
This is Awe-Some! 'Love it!
Do you, by chance, still have measurements for the pieces of MDF you cut out? It'd be very helpful
This is awesome!
oh dear lord portal blueprints you can read! <br>you already won life by making this, you don't need to try again :P
what was the total cost? i'd love to try and make it but it looks so expensive with all those customized laser cut pieces.
So...I'm actually going to be building this using your tutorial for my engineering class, thanks to your brilliant documentation! Just a few questions though... Is it important that the paint be Valspar? On one of your parts lists it merely says &quot;primer&quot;...does this refer to the Valspar? If not...what is it exactly? Did you use any other dimensions of guides aside from the blueprints? If so, what? <br> <br>Thank you for your patience!
This is such a cool project! Im making some for my school project now, also making a defective one :P <br>Any possibility you could upload the full size resolution of the blueprints? to me at aldovisini@ gmail.com <br>
I absolutely love this project. only problem is, i have no clue whatsoever how to mold. i've never done it before. do you think you could explain the process in a much more simpler way? for instance: your materials for one of the molding processes were: <br> <br>Smooth-on Rebound 25 silicone rubber <br>Thi-Vex II silicone thickener <br>Smooth-on Plati-Paste <br>Mold release agent <br> <br>do you think you can tell me what order they go down in on the molding surface? and do they have to each dry completely before the next material is poured on?
I would recommend going here as they have far more information then I could ever give you. If it is something you are interested in, take the time and see what you can learn. <br> <br>http://www.reynoldsam.com/media.php
why didn't you put this one in the game.life challenge too?
(still alive (Portal)<br><br>Aperture Science
Wrong starting line.<br><br>*ahem* <br>This was a triumph
WAT WHY U NO PUT IN GUN SHOOTING SOUNDS !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
im going to make this, and then make a sentry turret(<a href="https://sites.google.com/site/projectsentrygun/" rel="nofollow">https://sites.google.com/site/projectsentrygun/</a>) and modify it for this!&nbsp;
i was wondering if the eye design was up on ponoko or if you could upload it some how. it would a great help to me<br>-halosk8ingking
Hi, this is so cool, I would really like to give it a shot at making a turret, I like the size you used, would you care to share the measurements?
My heart is melting. I love Portal, and the turrets are my favorite characters in any game ever. Fantastic Job. Just wondering, does it say &quot;I'm different&quot;?
How much would one of these cost to buy?<br>
Can you provide a schema of the electronics?<br><br>Or is that on another site?
Sorry I never drew up the schematics for this since it was really just connecting together pre made components. Don't think I would be able to go back from memory and create one as its been awhile since I wired it all up.
I too would love a portal turret. I would be glad to buy (one of) the one(s) you have already or a portal 2 turret if you decide to make one. 9998722@gmail.com I'm only 12 so my parents wont let me pay toooooo much for it but if you can, I can work something out
Awesome!Do you think you could make one for me? I'd pay for eveything, including shipping, and labor. podote@yahoo.com if your interested
Unfortunately I'm not building anymore turrets right now. Working on new projects!
Hey =) just a wonderful one, really love it.<br><br>I have a Q about how much smoth-cast you used for this project =)<br><br>=)
All the pieces used just under a gallon. All of the leg pieces are solid so that used up a lot of plastic.
Man, you really just kept on trying 'till you ran out of cake. And I am SO jealous of this. You should show it to someone at Valve. They may buy it. Or not.<br><br>Just... Amazing. <br>(Psst: The cake is a lie.)
hey, is it possible to use common bits and bobs instead of the laser cut pieces?<br><br><br>i think it might be possible

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Bio: I'm a 28 year old Nerd working as an animator in the game industry in Los Angeles. When I'm not in front of ... More »
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