Aluminum Parts vs Steel Parts

Is their a substantial difference if a robot is made from aluminum rather than steel.


Aluminum is lighter, Steel is stronger. That’s about it, although only certain parts come in Aluminum and Steel, so if you want certain parts or sizes you’ll most likely mix and match.

Steal is expensive, Aluminum is crazy expensive. Just like how the other guy said it, steal is stronger, but heavier. Aluminum is lighter but weaker. But its strength is still decent. You should only use aluminum on something that has to be very light. Its a waste of money if you use it for a drive train, or non weight sensitive parts. Even then, its just a waste of money.

We have always used steel. We bought an aluminum kit for 100$ once, the pieces are relatively useless.

I think the real advantage in aluminum is for use on arms and other mechanisms that extend far from the CG of the robot. The lighter aluminum helps keep the robot balanced, and allows you to make longer arms (or pick up heavier loads).

I agree about the drive train - keep everything below the “deck” steel.


  • Dean

I agree with most of this but I think that if your bot is already balanced, lowering the overall weight of it can only help in most cases with acceleration/turning. IIRC, aluminum was something like 40% the weight of steel and it’s stiffer than steel, making it pretty ideal for an arm. In order of priority, if you get aluminum

  1. Arm/heavy lifting mechanisms
    This enables you to either gear the arm faster or carry more, both of which are huge bonuses.

  2. Towers/anything above your drivetrain
    It lowers your centre of gravity, making your bot more stable and less prone to tipping.

  3. Heaviest other parts. Stuff like C-Channels that weigh a huge amount get lightened a LOT by the use of aluminum.

Also, IIRC, last year after we got and used our aluminum kit, we used about 80% of the aluminum in it and lightened our bot by approximately 1.3kg, ~3lbs which is pretty good on something that weighs less than 20lbs.

There is a “Long” Aluminum kit that became available sort-of recently - I like its parts much better than those included in the original Aluminum kit - Our club bought one.

My robot wouldn’t be able to move its arm without the aluminum kit, the difference in weight is huge. You can take several aluminum pieces and one steel part and the steel part could still be heavier.

does anyone know the exact ratio for the weight diferences?
that would be greatly appreciated

i think someone mentioned above 17:20 but it was also counting the other parts (wheels, brain, ect)
thanks again

Aluminium is 1/3 the weight of steel.


What happened to that page on the Vex website saying that the aluminum was 1/2 the weight but stronger than the steel?

The aluminum in the kit is thicker than the steel by a good margin. It’s definitely lighter by a lot though. I personally remember it being around 40% the weight of the steel equivalents while being competitive as far as strength goes. The only downside to the aluminum is that it is softer than steel so it does get scratched/dented by screws and nuts very easily.

Aluminum, especially the straps seems to be a lot weaker (easier to bend) than steel. One of the 254 teams actually managed to bend a short aluminum1x2 c-channel, but we did not experiment with a similar force on a steel c-channel.

Another option if you are looking for parts that are a lot lighter is the 1/4 pitch steel. Not only does it have a lot more holes, the metal is thinner. The 1/4 pitch c-channels are strong enough for almost anything that you would do in VEX.

I have used aluminium before. It is alright i guess. As far as chassis go if you have aluminium you may as well use it but for arms and other mechanisms that you can’t lift unless they are aluminum don’t waste your money on aluminum spend a couple bucks on latex tubing and use the data provided in other threads to counterbalance you arm (you can just wing it too but it won’t be perfect). i understand the idea of using aluminium to keep you CG in check but if you have to worry about you CG that much i think a redesign is in order because by lifting something like a football in clean sweep might mess you up just the same. I always try to make it do that i have NO worries about the CG.

just my $0.02

Personally I think aluminum is awesome. Now my team doesn’t have quite the financial restraints of most teams. Even so we rarely special order aluminum anymore. So it’s one of those things that is really nice because it is light, and escpecially in a challenge like clean sweep where the balls don’t weigh too much, it makes everything a lot faster. The strength of the stuff doesn’t really concern me but I’ve never put it through an excessivly rigorous test.

Anyway, when it’s there it’s nice to use but I’ve never built a design around it. There are better things to spend your money on if you have limited funds it but the stuff is kinda nice to have.