I once talked with a Lego Builder at the Florida park. He told me they use a glue that actually melts the Lego blocks together. With that in mind, I searched and found this article (on Facebook). It says Lego Park Model Makers
use a solvent based plastic weld. It heats the bricks up so the edges bind together. Obviously it has to be very strong to ...
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) ...
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 ...
In my case, it depends. On older minifigures from the 80's, 90's, and early 2000's it's okay. (I'm not saying it's a good thing) Sure, doing it too many times will gradually wear them down, but not enough to the point where the torso or arms break. New minifigures from 2012 and onwards though, NEVER TAKE THEIR ARMS OUT UNDER ANY CIRCUMSTANCES! Newer ...
Try to keep the track in mint condition. For example, don't expose it to extreme heat or cold. Keep it away from any pets or children who don't know better. Looking at some pictures, it seems that the vehicle on the monorail runs on a gear. Try interchanging gears every so often so that the gears don't wear and the teeth don't get bent or break.
Having them connected may actually increase longevity, at least for parts of the brick. This shields out light and air pollution. I have several LEGO bricks that were connected for 30+ years, and the sides exposed to air (and Los Angeles air pollution) were significantly more yellowed than the sides that were connected.
The track is pretty durable. I have several pieces of old track that the motor runs on well.
With the 3D printers now available I am hoping to be able to "print" some of the track with ABS filament. Getting the gear teeth just right will be the tricky part and the end connectors.
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.
Lego bricks can withstand a fairly high pressure before they deform, but Lego creations tend to deform more easily at the various connection points. Therefore it's possible to build a relatively easily deformed bridge using long pieces, such as technic beams. You could build a bridge that deforms easily and then show how it flexes under the various weights.
I have designed some special measuring tooling for my previous employer that uses strain gauges, but is is not always that easy. You need for sure:
glue them on the construction in the correct orientation
2 strain gauges on both sides for temperture compesation
a way to calibrate the measuring device or construction
this resulted for us that ...
I've found that when a hand is pulled out it often (but not always) creates a crack in the arm, so that when the hand (or another different-colored one) is replaced it'll be a bit loose. It could certainly depend on the age of the minifig tho'.
98% precent of all the broken LEGO pieces I own are colored in reddish brown. I've broken a lot of them too. Just broke one right now, in fact. They probably use a weaker type plastic on them. I seem to be the only one who's ever noticed this.
The ones that gave me the most trouble were the "new-style" BIONICLE axle connectors like this one:
It seems that the parts holding the axle ball were much thinner than on the previous versions, and they tended to crack and break from extensive use. It was possible to use some cracked ones, but some broke beyond that.