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Astonishing paintjob on all the models! I really admire the "pimp my tank" chaos kits as well! altough they seem a bit baroque to me, wich isn't a bad thing per se. I think elaborate decorations suits some csm legions better than others. And black legion happens to be one :) !

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Discussion Starter · #23 ·
As usual, thanks for the positive feedback; during frustrating builds like these tracks, it really is motivating. Everything is on track (See what I did there? clever, yes/no?) but a little behind schedule. Until I can get at least one more Pressure Chamber up-and-running (very soon) I can get caught in a catch-22 when I need to do casting and make moulds at the same time. With a little juggling I've kept things moving forward and the last new moulds will be done very soon.

I have finally got a Vacuum Chamber in the studio and got it to work right away. It's a very interesting addition to the casting process that took some experimenting to get right, but now that I'm getting the hang of it, I'm very pleased with the results. I'll be doing an article about working with a vacuum at some point in the near future. It's been fun learning the process, and it made it much easier to cast the larger 'Raider Track Links I've been finishing. Speaking of the 'Raider Links...

After some less than enjoyable bench work, the Proditor Pattern Land Raider Track Links are ready for the mould making process.

Everything in these pictures is either held in place with friction, gravity, or poster tack; if any of the fit looks a bit off, it's just because of this temporary fitting. One key point about these kits is that they will require the end builder to remove the small 'key' tabs that are used for the original GW links. It's just easier to remove the hidden tabs then to try and carve out a clean gap in these painstakingly crafted pieces. I would have literally blown a brain-fuse if I happened to ruin a part trying to do it. I completely overlooked them until I had several sections done, and potentially harming them was not a happy consideration at that point.

It's was worth the annoying effort in the end; these tacks really complete the transformation of the GW kit, if I do say so myself.

Where the Vacuum Chamber really helped with the 'Raider Links, it wasn't useful for the smaller Rhino Links. After fighting to get it to work with the vacuum, I ended up going back to pressure only to complete the kit. As tricky as this build was, it really did help me learn some about the limitations of each method (pressure and vacuum) and when to consider using each. Funny how the annoying mistakes usually teach you more then the easy successes.

To the left: Satisfaction with a job well done. Yep, these look awesome! To the right: Frustration given physical form in resin!

When you're building a prototype it needs to be really close to perfect. It's almost scary just what details will be replicated in the mould; even a trace of my finger print is forever immortalized in the back side of the odd part. So, any flaw that would take longer than a reasonable amount of time to fix was tossed into the rejection pile. So many lost links. *Sniff*

So, the all of the track links are done, and I am currently preparing them for moulds as I write this and also casting fresh pieces for stock before the moulds take over the chamber. The Proditor Vehicle Accessories are half moulded, and I'll show them once the entire kit is complete. They are turning out very well, and the Vacuum Chamber has been key in that success.

But that, as they say, is another story...

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Discussion Starter · #24 ·
Since the subject came up elsewhere, I figured this would be a good time to revisit a little tutorial about how I do my flat-top rivets. To start I'll say that I plan for all my rivets in my CAD designs; that ensures they will be accurate and well placed. When I use a needle pick to transfer the points of the design that I use to cut out a pattern, I also prick the center of each rivet placement. After using a larger pin to expand the hole I carefully drill each hole as a seat for the rivets I make. Made this way, the rivets are not just glued to the surface, but sit in a seat that keeps them from ever popping off from use.

Now with that said, first up, how the heck do you make lots of consistent rivets? Here's what I came up with...

I call it a Razor Rake. By super gluing spacers between several broken down lengths of utility razor, I get a rake of evenly spaced blades.

The plastic spacers combined with the actual thickness of the razor means I get an even spacing to cut uniform rivets. The plastic spacers just need to match the thickness of the styrene I'm working on - 0.4mm in this case. Once placed, the rivets will stand out a razor thickness in height.

Carefully rolling the 'Rake' over a piece of round styrene scores the plastic. Ready for cutting into rivets.

For the first rivet I start just inside the end. The first rivet will be too short to use, but it makes sure all of the following rivets are ready to go. Once I have the first group of lines cut I can place the first blade in the last line as a guide, and score another group of lines. Working that way I can covert long lengths of styrene rod into rivets very quickly.

I don't press hard enough to cut all of the way through in one go. There's two reason for this. First, the rivets will wedge themselves into the Rake; naturally, that's not good. Second, the blade deforms the plastic a bit and keeping the rod as one piece makes the next step possible...

A quick sanding on a fine grit sanding block will remove the minor deformation caused by the Rake.

I just roll the rod under my finger while sliding it carefully back and forth on the 320 grit sanding block pictured. It just takes a few seconds to smooth the rod back down, and the rivets are ready to cut.

The blade can find the scored lines very easily. With a quick rolling chop they each pop off. (Remember to get rid of the stumpy first rivet.) I find it best to carefully place my finger over the blade while I cut, so I can stop the freshly freed rivet from flying away. They get easily lost, as I'm sure you can imagine.

It won't take long before you've got a large pile of rivets ready to be placed. But then you run into the next problem. How the heck do you place that tiny rivet into its tiny hole? It took a bit of trail-and-error to come up with a surprisingly simple solution...

Prefect in its simplicity; by flattening the tip of an old Clay Pick I made a straight forward rivet pressing tool.

The rivets are so light that all you need to do is add a tiny bit of moisture (Read: spit) to the end of the tool, and the rivet will stick just enough to be placed. Carefully align the rivet to the hole, get it as straight as possible, and press gently but firmly. the flat tool applies even pressure, and most times the rivet will pop right into the hole. Most times.

Sometimes they will be stubborn, trying to go in crooked and deforming the rivet in the process. Rather than futz around with a 'bent' rivet, I just disposed of it and get a fresh one to use. They are easy to make, after all. On occasion the hole for the rivet will also be a problem, but a quick 'reshaping' of the hole with a drill bit gets things right. You don't want to drill the hole deeper, just clear out any glue residue - the usual problem I run into.

Once they're in place they just need a bit of clean-up and touch of glue to lock them in place. 8 down, 600+ to go... *Eye-twitch... twitch twitch*

I've become hooked on the pictured sanding sticks made by Alpha Abrasives. Perfect for all sorts of subtle sanding jobs where a file might be too stiff or aggressive; I use one to give the tops of the rivets a light sanding and make sure they are all the same height.

From there I add a tiny dab of Tamiya Extra Thin glue. The brush built into the lid makes it easy to brush the glue around the rivet. It doesn't take much, and it evaporates away into a very clean join, ready to be primed.

Anything as repetitive as rivets will be tedious to do. This process is no different. The build pictured here took over 650 rivets, each drilled and placed just like this. It can be a bit... daunting sometimes, but it's worth it for the final piece. Once you get a feel for the process and get going it actually progresses rather quickly. Here's hoping people find this informative.

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Discussion Starter · #26 ·
I am but a conduit through which the Dark Lords speak... They say I must scribe my trials so that others may learn, be inspired, and perhaps drawn to their cause. My hands are but an extension of the energies made real by the Warp... The Dark Lords gift me these ideas so that I might make them real. It would be blasphemy to turn from such gifts.

*Cough* Errr...

But seriously, thanks for the kind/positive feedback. Much more to come...

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Discussion Starter · #29 ·
Since the vast majority of my work is layered up, I just plan for the rivets in the last layer, and drill clean through. But yes, if the material is a thicker single layer I will use a mark on the bit with fine point Sharpie for depth if need be. With practice you don't even need it, you get a feel for drilling a bit shallow and/or use a taller rivet (made with a 0.5-0.75mm spaced Rake) and then file/sand them down to the desired height once they are completely dry.

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133 Posts
Simply great work. Threads like these are the reason we needs hobby forums. You have trimmed years off my hobby path.

Would you be able to delve a bit into your injection mold creation process? I've seen countless tuts on it, but I like your entire system so far. Also, you should put all these on a blog and I will happily send the link everywhere as the definitive resource on crafting minis from scratch.

Keep it up!

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229 Posts
Discussion Starter · #33 ·
Message received, I'll get some articles up about my mould making process. I've started a series, but I've learned a lot and added some new equipment to the process, so I'd like to update it from the beginning. This would be as good a time as any, I've been making many moulds the last while. As this post will attest to...

*In his best Eugene Krabs voice* “Prepare yourself for a tale of misery and woe! … And delay that skipping… Pirates don’t skip!”

Sometimes I swear projects have a curse on them. I try to be positive and ignore setbacks, and usually that's more than enough to get me through. Mistakes and challenges happen, after all, so there's really no choice but to deal and figure it out. Then there are those builds that refuse to co-operate, testing my resolve to the very end. Yes, I'm looking at you... track links, oh scourge of my recent existence! Apparently, the Dark Lords have some hidden lessons for me to find in these trials.

Several weeks ago I added a Vacuum Chamber to my growing selection of studio equipment. I had a good theoretical idea of how to use vacuum to help with removing bubbles, but there was a definite learning curve to figuring out how to get the desired results. Since I needed to make tons of individual links for the track sections I was building, I used the build to experiment with the new vacuum process. After all of those cast links (and they were a challenge in themselves), I thought I had it figured out.

Thinking I had the process sorted out, I started making moulds for the Rhino Tracks kit, and with that, the curse started messing with my mind. First, I managed to break the seal for two moulds I was making, and this happened...

I tried to adjust the mould boxes after the rubber was poured, but before it cured. Not a good idea.

Since I thought my plan was sound, I tried to economize my time and make several moulds at once. In an effort to get them all to fit in the Pressure Chamber I shifted the top moulds too much, with no idea that I broke the bottom seal. It wasn't until I opened the chamber that I discovered the mess it created. Lesson 1: If you're not careful, trying to save time can actually cost you time. I was trying to push the limit of the chamber, and now I know better.

Once that issue was sorted out (nothing to do but start the moulds again – this will become a painful trend over the coming weeks) I completed the set and got to work casting; and that's when my inexperience with vacuum casting came back to bite me.

When vacuum degassing, vents to let the expanding air escape are critical to the process.

I was trying to avoid gates/vents where I could, since more gates/vents equals more cleanup during assembly. These parts are reasonably small, so I assumed a vent on every-other-link would be enough. I was almost right... but almost isn't good enough in this case. The parts would cast (almost) perfectly, but small flaws keep appearing very consistently in every link that doesn't have a proper vent. I tried to modify the moulds by hand cutting some extra vents, but unfortunately it didn't work. Lesson 2: When in doubt, take the extra time to do a single test mould before committing to a larger set of moulds. I assumed this mould setup would work. Baaad assumption! *Hits assumption with a rolled up magazine*

Unfortunately, the vent issue only became really apparent after I had already started the moulds for the Land Raider Track Links. After seeing the problems with the Rhino Track casts, I knew the same issue would appear in Land Raider Tracks if I finished the moulds. So, I returned to the prototypes and added more gates/vents before re-starting the moulds.

Lesson 3: Dropping an uncured mould is bad. 'Nuff said?

Good luck cleaning up a sloppy mess like this while the rubber is still soft. It sticks to everything and smears everywhere. Better to just let the rubber cure, and peel it up later; and this is exactly what I did. While not really hard to re-make, naturally, the waste sucks.

Success! The added gates/vents did the trick, and the parts are now casting with virtually no flaws.

I'll be doing a much more elaborate article on using Vacuum during resin casting in the future. But for now, let me just say that once you get all of the variables worked out, the combination of Vacuum and Pressure is amazing for getting near-flawless casts. When done right, the success rate for casts is amazingly high. However, it's not a process that works perfectly for every kind of component, so it's not a 'one size fits all' solution.

The results with the Rhino Tracks were so encouraging that I was positive the Land Raider Tracks were going to cast just as well. I had taken the time to add the extra vents, after all. Well, it turned out there was another unexpected twist to be dealt with.

Just when I thought I had it all worked out, this strange problem with bubbles cropped up.

Lesson 4: Different components need different vent considerations; not all parts will cast the same, even if they are similar. The Land Raider tracks are a perfect example; all of the longer lengths of assembled links cast perfectly almost every time, but the single links keep trapping bubbles in the 'teeth' of the links. I'm not totally sure what's happening in this case. The parts are similar, so why is there an issue with only the single links? For some reason their size seems to cause bubbles to get really trapped in the 'teeth' with no chance to vent out. Whatever the cause, there was too many flawed casts for me to use these moulds. *Mutters a harsh curse under his breath* All of this would almost be comical at this point, if it wasn't such a waste of labour and materials.

Third time's the charm! With some final changes the newest moulds are finally casting really well.

Ok, so now for the light at the end of the tunnel. The track moulds have finally been completely finished, and they are all casting very well. Curse lifted… I hope. The accessories are catching up now that the tracks are sorted out.

Some successful casts up top; and a size comparison on the bottom.

Again, I’ll talk more about Vacuum Casting a little later. (I’ve already created a larger-than-expected wall-o’-text) It adds a layer of labour to the production, but also opens the door to an improved process for certain objects. If they are the right size and you can add a moderate vent, they will likely cast very well with this method. The search lights and smoke launchers are a good example. Two Dirge Casters, the vehicle Bolter ammo drums, and a few other bits-and-pieces are in the works. Such as…

Another example of a part that will cast much easier using vacuum during the process.

After kit-bashing an Auto-Cannon a looong time ago, some dark creature whispered to me from the Warp, telling me that I could make a bit to the same job in one step. It seems the dark entity was correct. It still needs some more detailing, but the idea is there.

So, for anyone who has shown interest, The Dark Works will be getting an update very soon with everything pictured, and a few other bits. I hope it’s been worth the wait. I can’t say I enjoy the process when it’s this stubborn, but I always like seeing it come together in the end. You defiantly learn more from your mistakes, and I’ve learned a ton that I’ll be taking forward.

More to come…

· Jac "Baneblade" O'Bite
8,078 Posts
Very interesting to see your trails and tribulations around casting, it's something that's not touched on openly too much by the community in general for obvious reasons. Are you keeping the miss-casts for personal use or have you just binned them?

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Discussion Starter · #35 ·
Normally, major mistakes are rare, so many times they don't get documented becuase they get overlooked in the rush to get things done. But this time there were so many problems one-after-another, it seemd a good idea to make an article about it. But also, this is the overall philosophy I've choosen for my studio; I am a firm believer in several things that others might not agree with.

Information should be shared, not hoarded and kept secret. Processes generally advance and improve much slower if they are kept secret; the power of the masses to consider and inovate new ideas is almost endless. Some may say, "Why would someone pay you to do this if you show them how to do it themselves?" and there's a grain of truth in that. But, knowing how to do something, and actually having the skills, time, and willingness, to do something are very different things, so I'm not too worried about sabotaging myself.

I try to show the good, the bad, and the ugly. While successes are great, and it's very helpful to see how to do things correctly, many times the best lessons are taught through mistakes. Not only does this show what pitfalls to avoid, but it gives people a true sense of just what it takes to do the things I do. Sometimes, if you don't have a deeper understanding of everything involved (good and bad) a process might seem almost effortless. Realistic expectations are good things.

As for miss-casts, I keep the 'almost good enough' casts for personal use, and the completely worthless ones are tossed in the trash. The rest get placed in a reject bin for later consideration. Most are too flawed to invest a lot of time trying to make them usable for their intended purpose, (better to just cast a new one, really) but they might have areas with details that can be cut free, cleaned up, and used in some other way. My current plan is to use these parts to help build shrines and intallations devoted to Chaos. I might also be building some larger scratch-build projects that these parts can be incorperated into.

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229 Posts
Discussion Starter · #38 ·
~ 2-Part Mould Making ~ Part 1

~ 2-Part Mould Making ~ Part 1 (Again, how I do it, at least. I hope you like to read... this is just the beginning)

1-Part vs. Split vs. 2-Part ~ Fight! For anyone interested I'll explain the difference... (Note: Everything I'm doing is self-taught, if anyone has any input for process or technique, I'm eager to hear it.)

1-Part Mould: If you have an object with a flat back (my Trim Kit parts being a perfect example) a 1-part Mould can be a perfect simple solution. Just mount the object on a flat surface or slab of plasticine, build a mould box around the object, and pour a slab of rubber over/around the item. Once cured and the prototype is remove, you'll have a mould that is gravity fed. Read: gravity pulls/holds the resin into the mould.

Pros: Simple to make, simple to use. Shallow/short objects will work well with this type of mould. If you take the time to poke and prod any trapped bubbles with a toothpick you can even manually remove most bubbles by hand. With slower kicking resin you'll have plenty of time to get a casting 'just right', and you don't need to invest in a Pressure Chamber or anything more than some basic mould making tools and materials. Perfect for someone who just want to make a few of some creation/s.

Cons: Slow and messy to use, and more limited in the objects it can reproduce. If the object is somewhat complex you need to slowly pour/inject 'just the right amount' of resin into the entire void. Then you need to go around and carefully remove bubbles. If you're just making a few of something for personal use, this is fine; if you're making lots of something, that's far too much labour-per-item. You also need to find a way to flatten the back of the resin (surface tension will make the resin back want to 'curve'). Messy option 1; use a flat object lubed with mould release as a second half of the mould and lay it over the poured object. This usually causes some excess resin to squish out, and makes tons of flash. Messy option 2: 'Skim' or scrap the liquid resin to level the back. Not only is this messy, you can still have surface tension problems. Messy option 3; Pour a little extra into the mould to make the part bulge a bit, and remove that with aggressive sanding after it’s cured. Lots of extra work, and so... much... dust... 'Nuff said?

Split Mould: This type of mould is a lot like a 1-part mould, but for objects that are much larger and complex. You setup the prototype and pour a large slab of rubber over/around the object. Once the rubber has cured the prototype will need to be carefully cut free (Read: split) from the center of the rubber block. When you start getting into objects this large and/or complex you usually need to start considering how to deal with bubbles in places you can't even see. Again, if you're just making a few copies of an object, it may be fine to just fill and repair the bubbles each time, but it adds significantly to the labour-per-piece.

Pros: Simple to make*, simple to use, and works well with Vacuum degassing. *Once you learn how to cut a prototype free from the rubber (this does take practice to do really well) this is an easier way to make a more complex mould. Pouring the rubber is simple, since it's usually a top down gravity fed mould with a single gate/vent. Since you don't need to set up for a second half (cutting the mould open creates the two halves) all you need is a prototype with a nice large pour gate, maybe some simple venting, and pour a block of rubber around it. Vacuum degassing will cause bubbles to 'boil out' of the resin rising up-and-out of the object and into the large simple pour gate.

Cons: Mould slip, mould lines, massive pour gates. Without anything to really lock the split of a Split Mould in place, it can easily misalign and produce a significant mould line or even a bad 'slip'. Slips are when the sides don't even come close to meeting; a bad mould line that is next to impossible to easily remove, usually requiring reconstruction of some sort. I hate all of these issues, so even when I end up doing large gate Vacuum friendly moulds, I will avoid using true Split Moulds. I swear by full 2-part Moulds. And the Pour Gates, massive Pour Gates. Resin is rather inexpensive, but it's still not free. Every CC of resin lost in the Gate and Vents could have been used to make more objects. In this case, more and less is always better; more parts, less waste? Yes please!

2-Part Mould: These start much like the 1-part mould, but the process follows with a second slab of rubber to make... you guessed it, a second part. This method can make gravity fed moulds, or my preferred, injection filled.

Pros: Control, precision, consistency. You can control exactly where the mould line runs; along edges, corners, and over easy-to-clean places to avoid detailed places. I hate mould lines. I insist on trying to make them easy to get rid of. Also, if you take the time to make many mould 'pins' to lock the mould halves together, with lots of staggered pins (more on that later), the halves of the mould lock together very tightly. I rarely ever have any 'mould slip' and always have reasonable mould lines when I cast thanks to these pins; I lose many many more parts to bad bubbles and voids than slips. Finally, you also get full control of the channels and gates that you use to inject or feed the mould with resin, and you don't end up with massive Pour Gates and Vents consuming lots of resin, if you do it well.

Cons: These moulds take more labour, skill, and materials to produce. Not only does each mould need to essentially cure twice (once per half), anything other than a flat backed object takes more time and skill to make the mould. Plasticine is your friend when making a 2-part mould; it's not only used as a base on all of the moulds, but also essential filler for more complex parts. It can take many hours just to build the plasticine to occupy the negative space that's required for complex objects, but the resulting flexibility you get in the mould is worth the time.

For me, 2-part moulds produce excellent reproductions with virtually no mould lines and only a bit of flash. They also waste less since you don't need a large pour gate like the Split Mould method. The amazing quality of the reproductions is well worth the effort, if you ask me.

Ok with that wall-o-text done... on to process! First, a few key tools and materials you'll need for this method.

  • Lego, lots of Lego. (Mega Blocks also work well) Hands-down this is one of the most straight forward materials for making mould boxes. Modular, endlessly reusable, and prolific, Lego lets you make any shape or size mould box you need. Lots of 2x4 blocks are perfect.
  • Plasticine. The same stuff you played with in school, Van Aken Plasticine can be found a most craft and hobby stores. You can even pick your favorite colour.
  • A Rolling Board. I've taped down a square of Parchment Paper to a cutting board for this task. Parchment is use the world over as a non-stick surface for all manner of jobs. You can find it at most grocery stores.
  • A Rolling Tool. A proper rolling pin is fine, but I make due just fine with a short length of rigid PVC-like tube.
  • Spacers. Just some thin strips of wood that are even and about 1cm thick. This will let you roll an even slab of plasticine.
  • A poking Tool. To errrr... poke, with. :) More specifically, to poke mould pin holes; but more on that shortly.
  • A scraping tool. A long tipped painting knife is perfect.
  • A Long Spatula. I use an icing spatula for mixing the rubber, to be more specific. But a few Spatulas for scraping rubber off tools and out of mixing cups is a good thing.
  • A Strong Mixing Stick. Always mix your rubber well before you pour it. Unmixed rubber will take much longer to cure, or not cure properly at all.
  • Mould Release Spray. Prototype parts will generally pull free of the rubber without Release Spray, but the mould halves can be almost impossible to pull apart without some spray.
  • Gloves and Safety Glasses. Rubber is sticky and doesn't wash off; wear gloves and older cloths or an apron. Also, the last thing you want to do is get a splatter of it in your eye/s. Slips do happen sometimes; always wear goggles when mixing and working with the rubber.
  • Lots of Paper Towel. When working with RTV Rubber and Resin you’ll always need to have some towels to wipe up sticky messes. As a general side note, drop cloths and other ‘keep it clean’ considerations should be made when doing these processes. Drips, drops, spills, and all manner of things can go awry. (I once flung an open bottle of liquid plastic across the room, due to a heavy-handed slip of the hand) Be careful, protect your work area, and yourself.

First you need a slab of Plasticine that is smooth, even and large enough. Also, a mould box of Lego to fit the part.

Use the strips of wood (or other objects) Spacers on either side of the Plasticine while you roll it out. Rotate it as you go to try and get the shape you'll need. There's no problem trimming sides down and attaching them to corners to get rid of an inevitable rounding you'll get while rolling. Just blend the seam a bit with your finger, and roll them together. The Plasticine is so dense that air trapped in and under it is not affected by the Pressure Chamber. You just need a smooth flat top to mount your prototype.

Once you've got a large slab, make sure it's big enough to reach all the corners of your Mould Box. How deep the Box is will naturally depend on the object. This is a shallow trim bit, so three Lego blocks is more than deep enough.

When making the Box around the object, always remember to give the item plenty of room. You want nice thick walls of at least 1cm around the object. The thicker the mould, the less chance of warping when casting. In some cases this will mean moulds will be massive blocks, but with the right rubber, and planning in the mould, it will last long enough to offset the modest extra cost.

Just place the object lightly to use it for reference. Here's where to Poking Tool comes into play.

With a light press on the Mould Box you can get an outline to use for reference. Trim off excess Plasticine and place the prototype as a guide while you press the voids into the Plasticine that will become the locking pins. All I use is a simple rod of metal with a mark to keep them all about the same depth. You want them somewhat thin (so you can fit more) and rather deep so the really lock tight with the other half of the mould. I start with the corners along the outside edge, then add pins as evenly spaced as I can manage. Follow the Lego pattern in the Plasticine to help with the spacing.

Again, more pins = tighter locking mould. And don't worry if the Plasticine puckers a little where you press these pins in; as long as the prototype has good contact with the Plasticine base that's all that matters. You want a clean mould, but the Plasticine doesn't need to be flawless.

With the rows of staggered locking pins in place, the Mould Box gets pressed into the Plasticine base.

I stagger the pins to get as much fit as possible, and have them as close to the object as I dare. I want the mould to have no choice but relax to a perfect fit every time, and this many pins does that.

With a firm press around the edge the Mould Box is sunk ever-so-slightly into the Plasticine to create a seal. Take extra care that the corners are getting a good seal. You can use a tool to press along the outside edge of the Plasticine and help make sure the seal is tight. The odd tiny slow leak will happen, but they stop as the rubber thickens while curing, and just create a little rubber blob to remove.

Naturally, the prototype is also pressed down to stick to the Plasticine at this point. You want it to stick to the slab, but not really sink into it. A light but firm press is usually more than enough to get the part locked in place, but sometimes a spray of Mould Release will help a part stick. It tends to soften the Plasticine ever-so-slightly, before evaporating.

Now the Scraping Tool (Painting Knife in my case, but anything similar will do) is used to free the entire contraption from the board.

The Parchment Paper will help considerably when trying to get this off the board. It's a little tricky even with paper; work your way around the Plasticine and gently lift the entire piece as you go. You want to keep the Mould Box in place, so take your time. Without the paper the slab with be almost glued to most boards. Pressing the pins really bonds the Plasticine down, and you usually warp the mould when you're trying to lift it. Do yourself a favor and get some Parchment Paper. It's at your local Grocers, right by the wax paper, plastic wrap, foil, etc..

Room Temperature Vulcanizing (RTV) Rubber, Goggles, Gloves, and a strong Paint Brush Handle as a Mixing Stick.

I'm using Smooth-On products, but there are many other brands. In this case Smooth-On Mold Star 30. This RTV Rubber flows very smooth, Pressure Casts perfectly, and is surprisingly tough yet very flexible. It is also very stiff in a good way, and doesn't need mould boxes to help it keep proper shape. A good thick mould of this makes exact copies of even the most delicate objects.

Gloves and Goggles should go without saying. Again, this stuff can be messy, you don't want it on your hands, and the last thing you want is an accidental flick of it in the eye. You might even consider an apron or coat to protect clothes; or just wear work clothes that you don't mind getting rubber/resin on. You can't plan for accidents or slips, so be prepared.

I'm trying to find something better, but for now the Paint Brush Handel is doing fine as a mixer. The chemicals in rubber will settle and make it act very strange if you don't mix them up before you pour, so make sure you mix them well.

No super exact measuring needed, just a simple 50/50 mix and it's good to go.

Use a spatula to to scrape as much of the Part A cup into the Part B. With this product Part A flows much faster/easier than Part B, so I pour it first. Don't worry if you can't get every last drop out of the cup, just try to get as much as you can. I then start with the Mixing Stick to get the blend of A and B started.

Now I switch to a long Spatula to mix, scraping the sides, corners, and bottom carefully.

The mix needs to be complete. Any poorly mixed rubber will make a soft spot in the mould. So you need to take time and care to scrape the sides of the container, and be sure to get it mixed out of the corners and off of the bottom of the cup. The RTV rubber cures very slowly, so you have a lot of time to work with it. Make sure the mix is very complete for the best results. Using cups that you can see through helps considerably, since you can actually see if the mix is compete and consistent with no streaks.

I use an up-side-down cake pan as a base for my moulds; it's stiff, fits the Pressure Chamber perfectly, and has a useful non-stick coating.

With the RTV rubber mixed, I let it sit for a few minutes to let the larger bubbles rise up and out. A quick blow on the surface will make the bubbles pop. Mixing will inevitably add lots of tiny bubbles to the rubber. Curing it under pressure will make them all completely vanish, but I give larger bubbles as much chance as I can to rise out.

Pour slowly from one corner of the mould; let the RTV rubber slowly creep over the part. Again this minimizes the chance of trapping air bubbles. But even if a small one does get caught, the Pressure Chamber cure will get it.

Lego is also great because you can build stilts for extra moulds. This time I cured a second mould stacked on top of the stilts.

Once it's in the Pressure Chamber I make sure it's very level. Liquids will always settle flat, so leveling the mould never hurts. In this case it's even more important. With my Trim parts I need to clamp the moulds in simple Mould Boxes to get good results. If the mould is perfectly level, it will clamp better at casting time.

With that, I seal the mould up in the Chamber, and apply 50+PSI of pressure during the 7 hour cure time.

Well then... this has been quite the wall-o-text, and this is just one half of a simple 2-part mould. Granted, the first half of the process is more involved, and takes more time and effort. Part 2 will be shorter, since the second half of the mould can use this first half as a base.

Thanks for reading; I hope it's been interesting.

· Entropy Fetishist
4,224 Posts
Pro as hell. You have mad skills and dedication, Subtle, and have my admiration for it.

I also have bemoaned the fact that the only CSM aspect to their tanks are racks of spikes that break off in transit, and that they're otherwise essentially loyalist kits. This solution represents a whole lot more work than I could expect myself to put in, but if you're going to be doing the legwork... well, I might have to look long and hard at your store, there.

I'm also a bit proud to have pulled a similar heavy bolter -> autocannon kitbash, though I've mostly used reaper autocannon front halves.

Fantastic work here. I can't congratulate you on the quality you've achieved here highly enough.
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