I would like to build a LEGO model which is unbreakable.

What is the best approach?

I am not looking for just glue here.


I don't just want to strengthen the bond between the bricks, but the model as a whole. The level of force to withstand is in the area where it would actually break a single brick.


Has anyone tried the kind of spray on film you can use to protect your car from bumps? How does these kind of product react with LEGO plastic?

Also important is that whatever I would use should not add a thick layer on top of the LEGO, it needs to retain it's original size to some extent. A millimeter or maybe two in some places could be ok.

  • 1
    I think, as @zovits mentioned in their answer, you should clarify what kind of model you are building and what kind of damage you expect it to withstand. Also keep in mind that some pieces are more fragile than others. Finally, consider that the Lego company just glues models when they want them permanently assembled. Jul 13, 2015 at 13:53

4 Answers 4


Is there a specific scenario in which it should be unbreakable? You definitely should use different techniques to prevent a spaceship from falling apart when dropped from a meter and to prevent a brick wall from separating when hit by a rolling football.

For System bricks using larger, longer bricks in overlapping configuration (think real life bricklaying) will certainly strengthen a model. You can also experiment with SNOT building to better withstand forces from other directions too.

For larger models a Technic skeleton can be built to be surprisingly strong, especially if you can anticipate the direction of the force and build accordingly.

Another approach to consider is to not build a single unbreakable model, but to plan it so that it has a few predefined breaking points where it will come apart. Then you can always put it back together easily. But of course it depends on your specific use case.


This is really nearly impossible unless you have a lifetime supply of super glue.

A good structure using Technic LEGO bricks will provide better support and a lot more "stick" to each other, making the creation less breakable. Building the structure in which the strongest side will take the most hits/pressure should be an excellent way to make the model unbreakable. Joining a Technic skeleton with other bricks should improve your model's durability. Technic and regular LEGO bricks create the best possible way for models to not fall apart.

Overlapping bricks (longer bricks preferred) like bricks can make a strong support for each other. Each piece helps each other support a piece, having no weak points unless layered unevenly.

Try making your models fall and see where they break most often. The place where they break off is probably a weak point and needs more support or the pieces used are just too weak for the job. Replace/rebuild to improve the overall structure of the model. Of course, long bricks are preferred as the pressure is more evenly placed, making the hits seem pitiful against the strong model.

  • Thanks for the answer, but I did not mean literally unbreakable. I was mostly asking for techniques other than glue to harden the model.
    – firelynx
    Jul 11, 2015 at 8:52

It's hard to answer this question without knowing more about the model in question. Something like a small Lowell Sphere would probably be made 'unbreakable' by a little squirt of expanding foam insulation inside. A Technic vehicle would be a whole different problem.


You could glue each brick together from inside the brick.

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