Long Time, No Post

I've been busy cranking out all sorts of things in the workshop lately.  Since there's been nothing I can call "finished" I figured I should still post something to keep people interested in this blog.

For lack of anything better to share, here's a video of a Russian T-72 Tank being rapidly disassembled by a Javelin missile:

By "rapidly disassembled" I mean "blown right the f*ck up."  45 tons of lethal combat vehicle becomes a few truckloads of scrap metal in a matter of "right now."  According to the video, the engine was thrown 65 meters away from where it started.  That's a V-12 diesel engine thrown two-thirds of a football field away!

Kaboom, yo.

Star Wars Republic Commando Helmet Part II: the Mold

When I last wrote about this project, I had finished the prototype:


The main problem with the prototype was that it was fragile, heavy, and pink.  In order to make it into something I could wear, I needed it to be exactly the same size and shape but made from a different material.  Time to make another mold.

If you read my article about molding the Mass Effect pistol, you've seen how to make a two-part box mold.  If I decided to go the same route with this massively larger piece, it would require a small fortune in silicone rubber.  Instead, this project calls for a rubber jacket mold with a rigid mother mold and rather than simply pouring resin in until the mold is full, I would be using a process called "rotocasting" or "slush casting" in order to make hollow copies.

The first step in making the mold was to add a bit of material around the neck in order to make sure the mold would trap resin around the bottom of the helmet and make the open edge nice and strong.  I used a piece of large plastic tubing I had sitting around the shop and built up around it with oil-based clay:


Once it was firmly held in place, the next step was to mix a batch of silicone and cover the area around the bottom of the helmet:


As usual when I make molds, I'm using AM128 moldmaking silicone from aeromarineproducts.com. If you buy anything from them, tell them Shawn Thorsson sent you. Sooner or later, they'll give me some sort of endorsement deal.

A NOTE ABOUT THE POTENTIAL HEALTH RISKS ASSOCIATED WITH SILICONE RUBBER: It smells like grape Kool-Aid.  Do not let that fool you into tasting it!

Enough said. 

In this case I decided to add a bit of accelerator to the catalyst because I'm impatient and I don't mind the fact that it makes the resulting rubber a bit stiffer.


I let it sit upside-down for a few hours so the rubber could cure on the bottom before I flipped it right side up and started brushing a thin coat of silicone over the whole thing.  This first coat, often called the "print coat" is the one that has to pick up all of the fine details of the surface:


In the photos above, you can see lots of places where the plurple silicone is very thin and the high edges are showing through. In order to make sure that the mold is thick enough to resist tearing when the castings are pulled, you need to add more silicone. I'm using the same AM128 silicone as the plurple stuff, but with a different catalyst.  The pink catalyst has a thixotropic additive that makes it viscous enough to cling to vertical surfaces. 

This stage is a bit like frosting a cake.  Here's the whole thing with a quick layer of pink thixotropic silicone spatulated* over it:


Once the pink silicone had cured enough to stay in place, I used a bit more pink silicone to build a mohawk ridge of silicone along the top of the helmet.  Then I put on one more light coat of the thin plurple silicone to make it nice and smooth.  This eliminates all of the little barbs that would lock into the rigid mothermold once it's built.

Here's a shot of the mold at the end of the 2nd day worth of adding rubber (it's the one on the right):

The other two molds are for my Isaac Clarke helmet from Dead Space.  More on them some other time.

The next day, I started laying up the fiberglass mothermold:


Before laying up the fiberglass, bear in mind that you're making a two-part shell.  To make the flange at the separation point, you need to build up a clay wall for the fiberglass to lay against:


I used an inexpensive fiberglass mat and polyester resin that you can buy at any hardware store.  You can use plaster of paris reinforced with bandages or strips of burlap (the cheaper, heavier option) or a product called "Mothermold" or "Plasti-paste" (the lighter, more expensive option, but I've found that fiberglass is the best compromise for what I'm doing.

Once the fiberglass had cured on the first side, I trimmed the excess from the edges and removed most of the clay wall:

I did leave some of the clay behind to act as caulking to prevent the fiberglass resin from the other side from seeping down and gluing the two halves of the mothermold together.  Then I coat the clay and fiberglass with a liberal layer of petroleum jelly to prevent the two halves of the mothermold from bonding together.

Then I laid down the glass on the second side:

The next step was to trim the edges on the second half and pry them apart:


It was a bit of work, so I probably missed a few spots with the petroleum jelly.  Still, I managed to pop the two halves apart:


After removing the mothermold, the next step was to make a relief cut up the back side of the helmet:

You'll notice that the cut is not at all straight.  This is to make sure that the two halves are properly aligned when it comes time to reassemble the mold for casting.
After peeling the rubber jacket mold off of the prototype, the next thing you want to do is leave it inside-out for a while so it can air out:


When you're ready to make a casting, you need to reassemble the mold and mothermold:


The rotocasting process is pretty straightforward.  You mix a batch of resin and pour enough into the mold to coat the entire inside.  Then you roll the mold around so that the resin flows over every surface inside the mold.  When it cures, you have a shell in the same shape as the mold.  If you need it to be stronger, once the first batch has cured enough to stay put, you pour in another batch.
In the case of this helmet, I did five pours.  The first two batches had microballoons mixed in in order to reduce the weight of the final casting.  The third batch had milled glassfiber added in to make the cast stronger.  Then the last two batches had microballoons added again.

In the end, here's the helmet cast when it was still in the mold:


Here I am wearing the first cast while holding the prototype:


Here you can see the cast and prototype sitting between a copy of an episode III clonetrooper helmet from Master Replicas and a Republic Commando helmet from another maker whose name I don't recall:



Having served its purpose, the prototype is no longer needed:


I'll be casting a few more of these and then painting up a few as well.

Stay tuned for Part III: Wiring and Painting.

*I know I'm using this word incorrectly. "Spatulate" is an adjective that means "shaped like a spatula." I'm trying to repurpose it to be used as a verb meaning "to move and/or compress something with a spatula." Please do the same. I figure when I hear Martha Stewart mention spatulating something in the kitchen I'll have had a lasting impact on the English language and I can move on to other life goals.

Target of Opportunity

I've been teaching my niece proper geekery lately.  Today's lesson: whenever you see Jar Jar Binks, you have a moral imperative to punch him in the junk.


Right before we left, I told her, "now strike him down and complete your training."

"Good...  Good."

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HALO: Helljumper

A while back I was contacted by an aspiring film maker in New York who was looking to start work on a HALO short film.  Here's a promo poster he's been posting around NYC for the casting call:

You can read more about the project in the blog: http://blog.helljumper.com/  He'd heard somewhere that I could make prop and costume items and contacted me about building a few things for the project.  So I'm mentioned as the guy that's making the Marine armor and helmets as well as some of the weapons.  

The other two guys mentioned as making props and costumes are the very talented Sean Bradley and the equally skilled Lee Calhoun. They're both great guys and I actually own some of their work as well.

What I'm really looking forward to is some of the test footage showing off people actually wearing my stuff.  For now I have to be satisfied with his pitch video:

While they're rounding up funding I'm doing all sorts of things, such as putting the finishing touches on this beauty:


I'm pretty proud of this particular sniper rifle.  I'll be sad to see it go.

Check out the Helljumper blog and stay tuned for more...


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Star Wars Republic Commando Helmet Part I: the Prototype

Some time ago I got very hooked on the Star Wars video game Republic Commando on the XBox.  The game is a squad-based shooter in which you play the leader of a team of clone commandos, specialized clone troopers at the outset of the Clone Wars.  The game begins at the end of Star Wars: Episode II and carries you through all sorts of campaigns that took place before the beginning of Episode III.

I got so hooked on the game that, in a very rare-for-me foray into the expanded universe of Star Wars novels, I actually found myself reading the novels which were based on the video game which in turn was based on a set of characters which didn't even appear in the movies to begin with.  Before this happened I could at least claim that, while I was a huge geek, at least I wasn't geeky enough to read any of the Star Wars novels.  This game is what pushed me past that particular point of no return (as if owning a suit of custom stormtrooper armor* wasn't enough already).

Since my affinity for these Republic Commandos wasn't about to go away, I decided I might as well build my own rendition of the costume.  So a while back I started building a pepakura helmet based on a model from Skip's Pepakura files. When I say "a while back," what I mean is something like November of 2009. Here's how it started:

Once the pepakura model was built, I was pretty happy with the sizing:

Here's a side shot:

If anyone's wondering about the scale of this thing, I'm 5'7" tall with an average build.

All of the papercraft work was done while I was out at sea working on a container ship. Once I'd returned home, the model had gotten a bit mangled. Since I was never especially happy with the shape of the dome, this wasn't terribly heartbreaking. Instead, it provided the perfect excuse to cut up the model and splice it onto a child-sized skateboard helmet. Once it was securely attached, I layered on a whole lot of Bondo:

Because I have a tendency to jump the gun on things like this, once I'd done a bit of fairing and sanding, I couldn't resist the urge to put a coat of black primer on the whole thing:

And as long as I wasn't resisting urges, I went ahead and tried it on again:

After that, it alternated between hanging on the wall where it wasn't being worked on and sitting on the bench where it wasn't being worked on. Occasionally I'd have a bit of down time, notice it staring at me, and spend ten or fifteen minutes sanding it or spraying another coat of primer on it. But in all honesty, this was just a backburner project for well over a year.

Then I decided it was starting to annoy me.  For no reason I can think of, this particular project seemed to somehow represent everything I was neglecting.  It just sat there staring at me, taunting me, vexing me. It was as if the helmet was shouting out, "Go on, finish me.  I dare you.  But you won't.  Because you are a failure..."

So despite the fact that I genuinely had more vital things to work on, a couple of weeks ago I pulled it down off the wall. I dusted it off.  Resisting the urge to give it another coat of primer, I got back to work. With a bit Bondo and sanding, the whole thing was starting to look pretty sharp:

Then when I scored in the seam lines on the cheeks and cut a few of the notches here and there, it really started to pop.  Just to be sure I sprayed it with a coat of white primer:

Thinking I was nearly done, I went ahead and sprayed it with my usual glossy prototype color**:

Here's the "intimidator" shot, looking up at the chin so it's imposing:

Here's a shot of the back:

Once I'd made it shiny and pink, I started noticing all sorts of thing I'd neglected to add to the build.  With a bit more tweaking, I added some more notches and the little light widget to the right ear:

The very last thing I added was this little recessed area in back of the cheek hollow:

Finally, I added a couple of fun bits to the underside:

At this point, I'm satisfied with the overall shape and finish of this piece.  Unfortunately, it's heavy and it won't hold up to much abuse.  It's also pink.  

So now it's time to make another mold.  Stay tuned for part 2: moldmaking...

*Stormtrooper armor, and a Boba Fett costume, and a TIE pilot costume, and a Darth Vader costume, and three different types of clone trooper helmets, and the list goes on...

**People often ask me why I tend to paint my prototypes pink.  The reason is that I want to have a nice smooth finish and the color isn't important.  When I first posted pictures of my Master Chief helmet prototype online, I was contacted over and over by folks who wanted to nitpick my color selection.  They all disagreed on what shade of green to use, but they still all agreed that I'd gotten it wrong.  Since then I avoid this whole argument by making it plainly obvious that I wasn't even trying to get it right. 

Rose's Rat Rod Glam Photoshoot

The other day Richard Small of Richard Small Photography contacted my sister Rose to pose for a set of glamor shots with a rat rod down at Infineon Raceway.  Looking at his website he's done a lot of great work, so she was looking forward to it.

Here's one of the splendid results:

And another that focuses a bit more on the car:

More pictures after the jump. Enjoy.

Building the M-3 Predator Heavy Pistol from Mass Effect 2 Part Two: Moldmaking

When last I wrote about this particular project it was all sorts of good-looking, like so:

As I mentioned at the time, it looked good but it was cobbled together from a variety of materials and it was a bit on the heavy side.  Plus, it suffered from an unfortunate case of being the only one I had.  Since I needed to send one to someone else and I wanted to keep one for myself (and I would probably make a few to sell to friends to offset costs) I had only two choices.  Either I would have to invent some sort of molecular replicator technology or I'd have to make a mold. 

I went with the mold making option.

The rubber I'm using in this case is AM128 Silicone RTV (Room Temperature Vulcanizing) moldmaking rubber from aeromarineproducts.com.  I buy from them because theirs is the lowest price I've found for silicone anywhere.  Even with the cost of shipping.  

AM128 moldmaking silicone also smells like grape-flavored bubble gum.  Don't eat it.

Silicone is a wonderful thing.  It has the ability to stick to nothing at all.  This is why you see so many cooking utensils made out of different grades of silicone.  In fact, the only thing that can stick to silicone is more silicone.  When you make a mold out of it, that means you can pour resin into the mold, wait for it to cure, and pull the cured part out without using any grease or mold release to prevent it from sticking to the mold.  It also has amazing detail reproduction properties.  There are actually certain grades of silicone that are used to duplicate cellular structures for later study in medical applications. 

There are a lot of different ways to go about making molds and each is great for certain things.  In this case, I opted for making a simple, two-piece box mold.  This means I'll have two chunks of rubber that fit into a box and there will be a hole in between them that's exactly the same shape as the original model.  When you pour resin into that hole and allow it to cure, it will form a copy of the model.  Here's how.

To make a box mold, you start by making a box:

This particular box if made out of Medium Density Fiberboard (aka "MDF") that's 3/4" thick.  There are better options for these applications, but none of them were laying around in oddly sized and shaped scraps all over my workshop.  So MDF it was.

When building the box, the key thing to do is make sure you've got 1/2" of clearance all the way around the original model:

As you can see, I'm making both parts of the pistol in one mold.  This way I don't end up wasting a bunch of time and silicone making a whole 'nother mold.  You also want to make sure that the box won't leak.  For that, I just pushed a bit of oil-based clay into the seams to act as a sort of caulking.  Finally, you'll be taking the box apart a couple of times during the process, so use screws to hold it together.

Once I'd decided I liked the layout, the next step was to lay down a bed of clay to hold the model in place.  Since you'll be making a two-part mold, the shape you're making the clay in now will become the shape of the second half of the mold.

The first priority at this point is making sure that the model is tightly sealed in place.  At this point you're also deciding where the two halves of the mold will separate.  I try to follow along the edges of the model so that the seams will be easy to clean off.

Here's what the clay wall looks like once it's mostly formed:

When designing a mold, you have to give ample consideration to how the resin will flow into the mold as well as how air bubbles will flow out of the mold.  In this case I plan to pour the resin into the back end of the pistol next to where it's labelled "model 85C" above the grip.  Because air bubbles are likely to get trapped at the high points at the back of the grip and the rear sight, I've added vents there.  I've also set up "sprues" which act as pour spouts and vents between the main portion of the pistol and the removable body panel.  Those are the white plastic tubes running between the two pieces.

Finally, you need to set up "registration points," which are little holes that will line up with the little bumps on the other half of the mold to ensure that the two halves are properly aligned.  In this case, I simply pressed the rounded end of one of my sculpting tools into the surface of the clay to make oodles of little dimples:

Satisfied that the clay wall was just right, the next step was to pour the first batch of silicone.  This is often called the "print coat" as it picks up all of the minute details on the surface of the original.  Here's the first pour of about 23 fluid ounces of silicone RTV moldmaking rubber:

A note about silicone: READ THE INSTRUCTIONS.  If the manufacturer says the material must be mixed to a certain ratio by weight, you're going to need a scale in order to do it right.  Do not try to eyeball it or you're going to end up wasting a lot of material in the best case.  Worst case you'll waste a lot of material and ruin your original model in the process.  There are some types of silicone that can by mixed by volume.  They tend to be weaker and softer and wear out faster.  If you've got a mold that has finally failed due to age or overuse, don't throw it away.  You can cut it up into chunks that can be re-used as filler.

Anyhow, after the second or third batch of silicone, it was becoming clear that this mold was going to use up a small fortune in rubber goo.  Fortunately, I've got a few other molds laying around in the shop that have long since given up the ghost.  So I hacked one of them into bits and sunk the bits into the still-liquid silicone to take up space.  They were a different brand of silicone, so you can see them as blue chunks:

Once I'd squeezed as many rubber chunks as I could into the silicone, I poured one more batch on top just to hide the fact that I had recycled rubber inside:

The main challenge at this point is to leave it the hell alone long enough to properly cure.  I actually had to take a whole day off from being in my workshop just to resist the urge to pull the mold apart before it had properly cured.

The next day, I flipped the mold over, unscrewed the bottom of the box, and started pulling the clay off of the underside:

With the box and the clay removed, the first half of the mold looked like so:

Notice that everywhere I put a dimple into the clay, there's now a bump in the rubber.

As I mentioned before, silicone doesn't like to stick to anything except more silicone.  Now we have to pour the other half of the mold, but we don't want to have the two halves stick together and ruin all of the cute little dimples and bumps.  In order to prevent them from touching you'll need some sort of mold release.  There are all sorts of commercial options available, but I've found that a very light coat of Vaseline works just fine.

Once you've coated the first half of the mold with silicone, the next step is to reassemble the sides of the box around the mold:

When you do this, you want to set the sides of the box a bit higher than they originally were.  This way, after you pour everything, the box won't be quite as tall as the rubber mold.  When you reassemble the box, you can clamp it together a bit and help seal the two halves of the mold together.

Once the box is sealed around the first half of the rubber mold, it's time to pour more grape-scented goop:

And more:

And even more:

You may have noticed all of the bubbles in the pictures above.  One benefit of building the box mold like this is that the bubbles rise away from the surface of the original model.  You can do a lot of other things to eliminate the formation of bubbles in the silicone (such as putting the mixed silicone in a vacuum chamber) but with this method you really don't have to worry about it too much.

After allowing proper cure time (in other words, resist the urge to screw with it), the next step is to disassemble the box and pull the two halves of the mold apart:

Now you need to pull the original out of the mold, clean off the Vaseline, and allow the rubber some time to dry out.  Even so, your first pull will likely end up with a bit of Vaseline residue or tiny bits of clay stuck to it.  I usually call the first cast a throw-away.

Once you've let the mold sit for a few hours, reassemble the box with the rubber mold inside.  At this point, you'll leave off the side of the box where your pour spout is.  Make sure to tighten the lid on the box just enough to squeeze the two halves of the rubber together so they won't leak.  If you make it too tight, you'll likely distort the shape of the hole you're about to fill.

Then set the box on end and pour resin into the pour spout until it fills up to where you can see it coming out of the vents.  As you pour, tap the mold or shake it gently to help any trapped air bubbles work their way out.  The resin I'm using is also from aeromarineproducts.com.  They have urethane casting resin in off-white (cheapest) black (a bit more expensive, but more reliable and faster to cure) and clear (most expensive, very temperamental and hard to work with).  In this case, I used their off-white resin with some black pigment added in to make the casting grey and microballoons added in to make it a bit lighter in weight.

Here's the first cast coming out of the mold:

When I mentioned that the silicone picks up details very well, I wasn't kidding.  The lettering and logos you see in these pictures were vinyl decals that were stuck onto the prototype.  They're no thicker than a sheet of paper and you can clearly see them and feel them on the castings.

For those of you keeping track, the mold took up something like 100 fluid ounces of silicone plus some leftover chunks of older molds.  The casting itself used up about 42 fluid ounces of mixed resin.

At this point, all that's left to do is cut off all of the "flashing" where a bit of resin has seeped into the seams of the mold as well as removing the extra plastic formed at the vents and pour spout.  That, and make another cast:

Or lots of casts:

Then all you need to do is find an appropriately attractive model to help show off your creations:

Stay tuned for Part 3: Wiring, Blinky Lights, and Painting.

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