15 November 2018

Old Elementary: Modulex and LEGO® brick connection techniques

Posted by Elspeth De Montes
A year ago we published an article explaining what the old LEGO® product called Modulex is, its history and useful resources about it. There were mixed reactions to the article, primarily because Modulex is incompatible with the LEGO System bricks we all know and love. Or are they? More recently we came across Ralf Langer, a German builder who seems to have a real knack for integrating Modulex into his creations. Ralf was happy to offer some insight into his methods.

I bought my first Modulex bricks back in June. I'm not quite sure why I finally decided to give it a try but most probably they were terracotta, a nice muted earth tone. I really like using muted colours and the Modulex colour Terracotta is a tone that seems to be suitable for roofs or decorative strips for houses.

I already knew that Modulex had totally different measurements to the LEGO System so I've never expected that some kind of 'real' integration would be possible. My aim was to find some techniques that would lock the Modulex without using the studs; e.g. with bars and clips or even with  Technic elements. There are actually many, many ways to connect Modulex and LEGO elements, as I recently learned, but I am focusing on basic elements here because they offer by far the most value in terms of use. 

The LEGO tile to Modulex brick connection

I originally decided to order a selection of cheap parts; a lot of Terracotta Modulex tiles in a variety of different sizes. Note that the Modulex System has tiles with and without tubes (as shown). If you get a choice, then chose the tubeless version as they are more flexible to work with in terms of positioning.

I always tinker around when holding LEGO in my hands and I always have some Tile 1x2 (Design ID 3069) lying around. It's one of the parts that my building style depends on, as they have no tube underneath and so are movable. This is a great tool for fixing holes when building out of System. It didn't take too long till I stuck a Tile 1x2 on to a Modulex 1x3 brick. I was quite surprised that the brick connected well with perfect clutch, it almost seemed like it was made for this. No forced, too-tight connection. Just a smooth fit.

Further investigation showed that a 1x2 plate did not fit, as the middle stud of the Modulex collided with the tube on the underside of the LEGO plate. Same with a Brick 1x2 (3004) but not with a Brick 1x2 without pin (3065). It seems we can integrate every LEGO 1x2 System element that does not have a pin. This includes: Brick 1X2 without pin (3065), Palisade Brick 1x2 (30136), Ingot (99563) and the most recent 'Jumper' Plate 1X2 W. 1 Knob (15573) – the earlier variations (3794) will not work.

Unfortunately, the '3 Modulex studs to 2 LEGO studs' ratio seemed to be the only one that worked and even then, multiples of the 3:2 ratio do not work, e.g. a 1x6 Modulex brick is much smaller than a Brick 1x4 (3010).
To be honest, being able to successfully connect a tile to Modulex parts was more success than I expected. This connection alone allows a variety of applications.

As the colour Mx-Brown is a little darker than Dark Tan, they go together quite nicely. The combination immediately reminded me of cardboard, which led me to my first little scene.

It is important to note that the Modulex brick fits in length but not in width. This is actually useful as the offset portion of the tile remains free for connection to a LEGO plate between the raised studs or to attach a variety of clips to hold the integrated section in position.

The post box to the left of the front door in the image below is an example of this technique. An Ingot (99563) was used instead of a 1x2 tile, and a Plate 1X1 W. Holder (4085) connects to hold the Ingot in place.

The house number is a printed 1x1 Modulex Tile, and this connection will be discussed later.

Modulex between LEGO Tiles in studs

The next technique starts legally, with LEGO tiles held between the studs on a LEGO plate. The gap between each row of tiles can then be utilised for holding Modulex.

Some of these Modulex bricks are connected to the tile, while others are simply held between the tiles with friction.  This allows variations in texture and surprisingly they hold very well.

As you can see above, the rows of Terracotta Modulex bricks and tiles are held in place by the Reddish Brown LEGO tiles to give an uneven paved affect.

Modulex tile on the LEGO 1x1 with vertical clip

Now we come to the technique that is probably the most versatile and useful! The Plate 1X1 W. Upright Holder (2555) can be used to hold Modulex Tiles firmly in place. I used this attachment within the house number in the mailbox example earlier. Discovering this technique was a major breakthrough for me, although I later found out that others already knew and had documented this connection.

It is important to note that not all Plate 1X1 W. Upright Holder are the same.

Only those in bold below will fit.

a. Plate 1X1 W. Upright Holder (Design ID 2555) rounded clip ends
b. Plate 1X1 W. Upright Holder (Design ID 2555) thicker squared-off clip ends
c. Plate 1X1 W. Upright Holder (Design ID 2555) thinner squared-off clip ends
d. Plate 1X1 W. Upright Holder with Center Cut (Design ID 93794)
e. Plate 1X1 W. Upright Holder - Rounded Edges (Design ID 15712)

The most important differences are within those with Design ID 2555. Type a is rounded while b and c both have straighter sides. There is a subtle difference between b and c,  but it's important. Type b will not fit as the square clip ends are thicker than c. Thankfully type a is very common despite the mould retiring in 2015. Type e is the current mould used, with improved engineering to avoid stress. The clip arms in the other moulds are liable to cracking and snapping off.

Connecting Modulex 1x1 tiles to a plate is quite useful since the Modulex system offers a wide variety of printed 1x1 letters and digits. 
If we continue with this particular connection and compare two similar walls, below; the wall on the left is mainly constructed with Modulex 1x3 tiles while the right version uses system Tile 1x2. In the picture the Modulex version looks quite nice, but the horizontal gap between each row is quite large so it is worth considering which look is better for your build.

Creating curves in your LEGO models by adding Modulex bricks

You can also link elements and bend them a little. The Plate 1X1 W. Upright Holder offers enough grip to set at angles. So, what do we get when connecting some tiles and angling them? Bendable arcs! This was like a dream come true for me.

Below is another example of using the Modulex Tiles held in place by Plate 1X1 W. Upright Holder to form the curved corned of the pavement.

1x3 Modulex Bricks with 2-stud wide LEGO plates 

Surprisingly, a Modulex 1x3 brick fits any 2-module wide LEGO plate (except for the 1x2 plate). Better still, Plate 2x2 allows three Modulex 1x3 bricks to connect, and it fits perfectly.

For all plate sizes longer than Plate 2x2, there needs to be gaps as every second Modulex 1x3 brick conflicts with the tubes under the plates. If that's not you want in your model you may prefer to connect multiple 2x2 plates together, as shown above.

So what can we do with this connection? The Modulex can be inserted to show the studs or the undersides, and both variations can be used vertically or horizontally.


The underside pattern reminded me of wooden tiles used in the garden or a balcony, so I made a little scene to demonstrate this technique.

LEGO Tile inside a Modulex Tile

I have another interesting trick for you that is a admittedly a little tight: a LEGO tile can be stuck inside a Modulex tile brick. When doing this with force you can see that the Modulex tile will slightly bend. I should point out that everything I am discussing are not legitimate connections and can stress your elements. So while a Modulex Tile 1x2 can hold a LEGO tile, don't push it all the way down! I recommend that your first attempts are with a larger length Modulex tile to get a feel for it, as the longer Modulex tiles are more forgiving.

This technique is perfect for those of you who like things nice and clean as it can result in some pretty, decorative strips when you insert the LEGO tiles in between the studs of a LEGO plate, as shown below.

Be aware that you have to somehow align the Modulex tile bricks to fit the measurements of the LEGO grid. In my example above, the Terracotta Modulex tiles (centre) have been aligned to the width of the LEGO wall and so you see gaps between each Modulex element. The Mx-Buff coloured ones (above and below the Terracotta) have no gaps between them but consequently are narrower than the width of the LEGO wall. In order to do a line without gaps you would need to use additional Modulex tiles. The alignment itself is easy, since you can simply slide the inserted LEGO tile along thus repositioning the Modulex tiles.

Remember the rows of Modulex held in place by Plate 1X1 W. Upright Holder?  Well you could also use this technique to create the same 'striped' wall.  Using Plate 1X1 W. Upright Holder has the advantage that you don't have to integrate LEGO tiles inside the wall as these may conflict with the inside structure. The only potential disadvantage is that you can see the Plate 1X1 W. Upright Holder are positioned between the rows of Modulex.

Obscure Connections

I've summarised in the image below a few more possible connections but I wont go into detail as these techniques seem rather obscure to me, although I have actually used them in my builds.

Continue to part 2 of this Modulex article where Ralf showcases some of his incredible creations that put all the examples to use.

All content represents the opinions of New Elementary authors and not the LEGO Group. All text and images are © New Elementary unless otherwise attributed.


  1. These buildouts are cool but Ryan Howerter showed us a ton of techniques years ago. https://www.flickr.com/photos/ltdemartinet/8331549172/in/photolist-dGeniw-fu26Ed-etGyuc-dB8XGu-dJE4ty-ggPw4X-dJKE4w-dPJKLw-8xgTEd-8xgTEN-fcgLXh-8QSRkp-cUYttQ-ffzdD7-cV6Koh-ffjZdB-dypNr9-eDjzgA-jH2VWP-f2eELo

    1. Yes, we've linked to those in the past but always worth another view!

    2. Hi Brian,

      Elspeth an I were aware of the techniques mentioned by Ryan Howerter and there are also many, many others (e.g. Brixe added quite a lot).
      I would say it's a different approach here; mostly different techniques and a different aim.

  2. I enjoyed this post.

    I would like to offer a suggestion for a future post (perhaps this could be a challenge). Can you review Clikits parts and their integration with system?

    1. I would second that, since I don't know anything about Clikits yet

    2. I have looked at Clikits colours (personally, not on NE) but perhaps Clikit integration could be a nice little project for Ralf haha

    3. Clikits parts actually seem easier to connect with regular System parts.

      Clikits icons with pins fit into Technic holes, into tubes and inbetween tubes at the bottom of bricks and plates, and placed offset on hollow Technic studs. Clikits icons with holes fit on regular Lego studs.


      I have a couple, both of Clikits and Modulex parts, that I found cheaply on thrift stores and similar, so I should probably use them for something, someday.

  3. I'm not sure if it's a typo, but I think the technique of placing tiles or plates between studs actually is illegal, since it puts extra stress on the parts, IIRC.


    1. Sorry your comment took so long to publish Håkan - it somehow ended up in a 'moderation' folder I never knew I had :)
      Plates are illegal, tiles are legal. They are microscopically thinner.

  4. I have a bit of a question on part 2555 thatI was hoping you guys may be able to help me with. I ordered a bunch from a BL seller in black, and some have a matte finish. They are still identified with 2555 underneath, but there is no (c)Lego stamped there. I'm pretty sure they are type 'c' in the picture above. The matte finish and absence of Lego branding made me think that they were non-Lego, but I remembered how many times the mould had changed and recalled seeing this article, so I thought I'd check in with some experts before I ask the question of the seller.
    Thanks in advance.