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Building Helms Deep

This Article is from GeBoom about his Helms Deep project. Im posting it for him as its very heavy with images. It truely is an AWESOME piece of terrain. I wish I had a chance to play on it.

Thanks a lot Gerard and I cant wait for the next part.

WARNING! This is a BIG article with BIG pics.

Helms Deep:
Helm's Deep

This article is about my Helms Deep project.

The article will explain my work up until the stage as you see it in the picture. The project will NOT stop there but as far as it is now, I think it is already interesting enough to write something about it.

The preparation:

Before actually starting to build Helm Deep I first had to find out how resin works and discover its positive and negative sides.

I started to build a large wall segment to see how this goes. First thing I did was to determine the length and height of the wall and ended up to making a wall out of plaster using the regular Hirst Arts building blocks.

The wall segment was 12" long and 5.5" high. This I used to make a large wall builder mold using Silicone. Next I made the pavement that goes up the wall using different sizes of chipped stone floor tiles. I glued this as a piece of 11" long and 2.5" wide, again molding it.


  • Resin Smooth On 305
  • Foam Board
  • Silicone
  • Plaster
  • Super glue
  • Acrylic Paints
  • Card Board
  • Filling material for gaps and cracks


  • Needles
  • Fine saw
  • Hobby knife
  • Ruler
  • Scale
  • brushes


The next stage was the experiment on casting these pieces with resin.

I tried to find out how thin I could go and what still was firm enough and workable. I ended up with large resin wall pieces that were about 1/8th of an inch thick.

Since the resin wall pieces are so thin they are very flexible but are not suitable for constructive work.

Building with flat resin casts is more like putting up wallpaper upon a wall so there you got the exclusive "wallpaper technique"!

I made a so called skeleton form of a wall piece out of foam board that I then covered with cardboard. Nothing fancy just the cardboard from cereal boxes.

Once the form is there you can start gluing the resin on to the form.

So what did I learn from this first resin experience?

  • Working with resin looks like a lot more work since you first have to make a mold and then have to build a certain form out of foam board and card board. But once you can start casting and applying the resin pieces it works like lightning (especially on larger basic structures)
  • Cast resin thin and it is flexible enough to make curved walls. Heat it up using a hair dryer will make it even more flexible. You can even bend it in to a circle (I will show this on the tower of Helms Deep)
  • It is rather expensive. I estimate that it has cost me about 125 euros just the resin alone to make Helms Deep. (approximately 155 dollars)
  • Working like resin in this way produces solid looking light weight pieces. If you make the test wall out of plaster you and op with a wall of about 4 kilo's. The resin test turned out to be a little under 1 kilo.
  • Resin does not break and chip off when you throw it to someone during a fight! OK the paint is likely to get damaged but that is about it.
  • Resin is an aggressive material and will slowly attack your mold. So beware of using resin in the original HA molds. A few casts will not hurt the mold but after a while the mold will get harder as if it dries out. It becomes less flexible and starts to get more and more attached to the actual resin cast until you tear the mold apart… I did get an average of 35 to 40 casts out of a mold using mold release. Still in the testing phase as this is concerned since the retailer told me that 50 to 60 casts must be possible.
  • Mixing Resin is rather delicate. A good scale is a must and it will also help you in preventing making too much resin for a specific cast. When not mixed well, the following can happen: Change in colour (no problem actually), casts that stay somewhat soft, casts that seems to keep on being sticky (sweating), casts that aggressively will cling on to the mold, cast that will not set at all.

{mospagebreak title=Getting Starting}

Starting on the real thing:

Why resin? You might ask.

Two main reasons I have for this:

  • The sheer weight of such a large project will be enormous. You may multiply the weight of the entire project by 3 when you want to build it out of plaster. This makes it also less transportable.
  • The fact that resin bends nicely in the round shapes of the walls without any complications.

Getting Information:

I tried to find as much information as possible about this structure. There is no official data concerning the exact measurements of the citadel so most of the work comes from looking closely at the pictures from the movie. Also the GW rule book of the LOTR game helps a lot although you will not find any information about this projects in that article also.

I did find some information of a person who started building Helms Deep who calculated everything from a certain centre point and that worked well.

The basic form of the citadel that consists out of an outer and inner wall and a courtyard is a half circle. Making a half circle means that there must be a centre point somewhere. That centre point lies directly in the middle of the large stairway in the courtyard, in front of the first step, that goes up to the hall in the mountain.

I estimated the radius being around 18" that led to a circle with a diameter of 36". Taking the playability of such a structure in to account and the bases of the miniatures also, I made the walls a bit thicker and the walkway in between the 2 walls a bit wider for better acc
ess. When drawing the layout of the project it is actually fairly simple since you work with these large circles. A straight line from the centre point (the middle of the half circle) will run straight through the centre of the main outlook post on the inner wall and run straight through the main gate. Divide the quarter circle again in 2 by drawing a straight line from out of this centre point and the lines run straight through the other outlook posts on the inner wall.

Just some reference points to give you an idea how I started to work on this project.

I used 5 mm foam board (1/5th" thick) as the base to work from. Starting this project made me decide to try and make it in parts that are easy to assemble and disassemble.

{mospagebreak title=First Some Drawing} 

First some drawing:

I draw these circle parts on to a foam board piece. The radius of this circle depends on how large you want to make the structure. In this case, for the Helms Deep project, It was all relatively simple. A walkway on the outside wall is 2.5" deep, The ramp that lies directly behind it is 4" deep, the inner wall walkway is 2" deep.

With a radius of 18" I get the following radius lines drawn on the piece of foam board:

18.0" (outside line of the outside wall)

15.5" (inside line of the outside wall and at the same time outside line of the ramp)

11.5" (inside line of the ramp and at the same time outside line of the inner wall)

9.5" (inside line of the inner wall)

What you have done now is actually spilt up the project in to 3 main areas. These determined parts can be used for 2 important things:

  • the base on which you build you project
  • the form to use for making custom blocks.

{mospagebreak title=The Outside Wall}

The outside wall:

So in the first place I concentrated on the entire outside wall. This wall breaks up in three pieces being referred to as the right side the main gate and the left side wall segments.

I cut out the base of the wall piece and copied it in order to create the top side of the wall as well. After that I made a few vertical pieces and connected the top and bottom foam pieces with these vertical pieces in between. Actually the basic form is set up in only a few minutes. Next stage is to cover the curved skeleton piece up with pieces of card board. Nothing fancy just card board from serial boxes will do the trick. Gluing this basic form together is done by using needles to help fixing the parts when glued.

The whole idea behind my approach is to make this form that I then can cover up with thin resin pieces. I choose for this option because working like this will save a lot on resin which is, compared to plaster, about five times as expensive as regular dental plaster.

The large wall builder mold I made for my test project was also suited for the actual Helms Deep project. In this case I assembled this wall builder in a way that there would be some difference in the wall structure so I used blocks of different heights and lengths. Important in this case is that you must be aware of the structure of each individual resin piece in order to maintain the same structure at the same height. Flipping a piece or assembling it a bit higher or lower will have impact on the consistency of the structure.

The concept on the project so far is relatively simple. You built your form roughly out of foam board and cardboard and start cover it up with resin pieces. This goes for 90% of the structure. There where you have openings in the walls, stairs and thinner walls you might have to work with normal cast blocks and build with them like you normally do with these blocks.

A custom build project like this will lead to making custom molds sooner or later. You do not need a wall builder mold but it speeds up the building process immense. The curved pavements on the top of the walls are hard to make with regular blocks. It can be done but it would mean that you must cut up hundreds of blocks individually in order to get a curved pavement.

I choose to make these pavements by making custom molds as I also did in my Amon Sul project as you can see on my website "

When making the custom block I focus on the right form. The thickness of the blocks is determined by the silicone strips I use with which I build up the temporary mold. Once the form is cast I will carve the stone structure in it using a dentist scraping tool. The stone texture is already on the custom made piece since I use a silicone surface with this particular shipped stone structure.

This technique is used for all custom blocks I made.

A nice example is the large gate piece. Again I used the same technique and carved the stone structure in it afterwards.

{mospagebreak title=The Main Gate} 

The main gate:

The main gate is a bit more complex. Simply because it has more angles and then there is this gate itself. The gate part is custom build made out of one piece, the same way as the other custom blocks are made.

To create more depth into the gate and to make it look more solid I placed two gate pieces behind each other. By cutting out the centre stone of the arch, I reduced the width of the arch. Now you get this bit smaller arch behind the larger arch.

All wall parts that can only be seen from one side are thin pieces of resin glued to the foam or card board underneath. All those parts where you can see the walls on both sides (mainly the top layers upon the walls) are made out of normal cast resin stones. This applies to the entire structure.

{mospagebreak title=The Ramp} 

The Ramp:

The ramp (walkway in between the inner and outer wall) are 2 separate pieces being a right side (flat walkway piece) and a left side (being the actua
l ramp that goes up to the second gate on the inner wall section.

For this part of the structure I made again a custom block. A simple form that, when cast multiple times, will create a circle shaped walkway by simply adjusting them side by side.

To determine its form I have this very simple method that I will explain below by the next series of pictures:

I started of drawing all the out and inside lines of the walls and ramp as you see "here". Now I have to split up the long curved form in reasonable pieces. A simple action that you can do any way you want.

Sticking to the ramp as an example I now draw a vertical straight line along the large ruler that still sticks in this centre point from where I calculated the radius for all lines. I shift the ruler a certain distance to the left or right and draw a second vertical line. Now I have determined the possible outlines of a possible custom block.

I cut out this form next and stick this from, using needles, on to the silicone template I made which has the chipped stone structure on it. Now I take the silicone strips of ¼" thick and form them around the foam piece with it chipped texture inwards. (towards and against the foam piece)

The silicone strips are fixed with needles also. When removing the foam piece, there will be a temporary mold that can be filled with plaster.

Once the plaster is dry I break down the temporary mold and get the plaster piece out. I scrape the piece, removing irregularities (mostly some in the corners of a piece made like this) and start scraping the desired outlines in to this piece. These outlines represent the idea of blocks, a pavement that is laid using different kind of blocks.

Once this is done I can make a mold out of this form and after that produce it several times to create large curved pavement.

The size of the custom pavement piece (how wide it is) is not that important you can choose whatever you want. You will also see that if you draw the lines (left and right side of this piece) exactly right meaning that both lines originate from the same centre point, the custom blocks line up perfectly creating a nice circled form. The same method can also be find in the Amon Sul project where I made a large ring of floor tiles of 2" by 2", creating a circle with a radius of 7.5" and was made out of 24 individual pieces.

As for the ramp the part that goes upwards;

I made this part using a piece of foam board and glued it, starting from where the ramp goes up, up to its highest point. Now I have this sloped form on which I simply stacked the individual pavement tiles in an overlapping manner creating a large stairway where the individual steps also are a bit up ward directed. (or downward depending on walking up or down) You can see this in the next picture.

The sides of the ramp are open but I plan on making some stone structure against it so it is possible to use the ramp with only the inner wall section or outer wall section.

One of the fun things is that making this project modular, you can actually set up pieces of the project rather then setting up the whole thing.

{mospagebreak title=The Inner Wall}

The inner wall:

The inner wall section is a one piece structure. I played around with the idea of applying the courtyard (just behind the wall) also as a loose part but eventually I decided to make it in one piece.

This part was again set up using foam board and card board. Besides the pavement tile I made for this part I also made the buttress block for underneath the small platforms that support the overhang of these platforms.

Since the radius of this part of the structure gets smaller, the curve gets sharper. Especially in this piece I used the technique of heating up resin and de-molding resin pieces at an earlier stage.

Heating up:

Resin becomes flexible when you heat it up. I would like to try the microwave but for now I have experimented only with a hair dryer and with a gas burner. (the gas furnace in the kitchen)

The furnace works best or better said, fastest. Once I heated up the resin piece I bend it in the desired shape and cool it with water. It sets in its new form directly. The wall pieces are rather thin so these parts get softer fairly quick and bend quite easily.

De-molding sooner:

The wall parts that are glued upon the walls are cast out of blocks that have the normal specifications as if they are cast out of normal Hirst Arts molds.

I made a special wall mold for these spots, the top wall pieces that are glued upon the walkways. These pieces are about 4" and are cast as straight pieces. Since they will be placed upon a wall that is curved I tried heating these parts up, as I did with the thin wall pieces, and tried to bend them also. Besides that I burnt my hands, the piece is too thick to get it done properly.

There is this other possibility that works much better. Once the piece is cast I have to wait for about 15 minutes until the mixture is set in a way that it is still soft but already hardened sufficient to get it out of the mold. Beware that the waiting time of the piece to harden depends on the type of resin you use.

The piece that is still soft can more easily be bend to its desired form. But if you then let go of the piece, the piece will slowly bend back to its original form.

No problem, the resin is still that soft that you can stick needles through it as you can see in the pictures below. I pin the piece down on a thick foam board piece and let it rest for another hour. The piece is now fully hardened and stays in the shape you pinned it into.

{mospagebreak title=Some Final Tips} 

Some final tips:

Cast what you need not what you like!

Resin is expensive so try to cast only those blocks that you will use. Always keep a mold at hand when you have some resin left. You can even fill up a large mold with leftovers. It is not a problem that it will be filled during separate casts.

Working with thin pieces of resin means that you will have to work with angles that are scraped in a way that they fit perfectly.

Now this will not always be possible or is too difficult. In that cast there is this great filling stuff that you can use. It is originally made for filling up holes and cracks in walls and ceilings.

Here are some pictures of the stuff and what it can do for you to help you cover up mistakes or irregularities in the structure.

So what should you expect to spend on a structure like this?

Adding up all the costs of materials I estimate the cost up to this stage at about 150 euros.

100 euros go into the resin so that is the most expensive part of the project. Rest is for glue, paints and foam board.

All in all I estimate the cost at a 200 euros which isn't that much money compared to the gaming piece you end up with.

{mospagebreak title=Some Additional Pics} 

Some additional pictures:

Posted in Terrain Building.

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