Is Welding Worth It?

[techhelpbb]

No one has mentioned brazing aluminum:
http://muggyweld.com/super-alloy-5

[JamesCH95]

Originally Posted by InFlight

On your riveted joints failing. It's very important to use the correct grip length and hole size for the rivets. If your riveted joints are failing constantly, it's likely some sort of installation error.

Welding Aluminum requires either a MIG or TIG welder. This requires some considerable practice, and mentor familiar enough with the equipment to teach others how to use it safety. It can only be used with some types of Aluminum, stick with 6061.

While not as strong as a weld, it is also possible to braze Aluminum with a plumbing torch. I'd only try this with 6061 aluminum and use Bernzomatic AL3, Alumaloy, or Durafix braze rods.

Originally Posted by techhelpbb

No one has mentioned brazing aluminum:
http://muggyweld.com/super-alloy-5

[techhelpbb]

Originally Posted by JamesCH95

Well they did not mention MuggyWeld.
So I think you could have snark lite on that but point taken.

[InFlight]

Brazing Aluminum is best done with a specialized Flux first to reduce the oxidation layer and help the braze to flow. There are quite a few different Aluminum braze rods out there. I just mentioned some.

Using a rod with flux in it is fine, but is a poor subistute for applying AL flux first. The Benzomatic AL3 rods are available at Home Depot stores, and are thus the easiest to find for most with no shipping.

[cpiravi]

Welding is totally worth it in my opinion. I have welded for my team for the past 3 years, and it takes a lot of practice and patience to get to a place where you can weld for your teams robot. It took my team mate and I a whole summer of practice to be good enough to weld our robot. This year, while I welded our competition bot I was training new students by having them weld our practice bot, so they are ready for next season. The many pros and cons robot wise have allready been said in this thread, and I also think it's a great thing for students to add to their resume, and a good skill to have. I know my teammate and I (and I'm sure many other students) have been given job offers and scholarships because we can weld. If a team can afford a welder and has someone to teach students how to weld, I think the pros definetly outweigh the cons.

[asid61]

Originally Posted by InFlight

Brazing Aluminum is best done with a specialized Flux first to reduce the oxidation layer and help the braze to flow. There are quite a few different Aluminum braze rods out there. I just mentioned some.

Using a rod with flux in it is fine, but is a poor subistute for applying AL flux first. The Benzomatic AL3 rods are available at Home Depot stores, and are thus the easiest to find for most with no shipping.

Do you have any comments about brazing versus welding AL? This looks like a really viable option for low-resource teams.

[InFlight]

I generally prefer riveted construction when practicable for frames. Otherwise bolted fasteners. Even with experienced teams, you'll have much more consistent build quality that way.

We did weld some steel bumper attachments this year. We've used some welded structure in the past as well. Welding is a useful capability, but it takes a lot of practice to make good welds.

There are some situations such as a swerve drive pivot tube that welding or brazing simplifies the construction details.

I've brazed repaired aluminum automotive parts. It similar to brazing copper plumbing, it's much easier skill to learn then good TIG welding.

[jeremylee]

We had problems in past with riveted joints coming loose over time. We have since switched to Avex 1661 series rivets in 5/32 and 3/16 sizes with proper sized drill bits that we keep stored in our rivet box. The 1661 series seem to be more forgiving related to misalignment and pull the material together very tight before snapping maintaining strong joints throughout the season. We didn't have any issues all year with our rivetted VersaChassis and we will likely use the same approach going forward.

However, if we had the ability to weld, we'd likely utiize it to simplify our construction in key areas of the robot.

[pHolmgren]

We've welded our robot for the past 2 years. When you design before you weld, it works out very well. We use aluminum TIG welds.
I would say yes, welding is very much worth it.

[Cory]

Originally Posted by Tom Line

As an afterthought.... look at some of the critical joints on 254's robot. They are both welded, and riveted.

They are generally only riveted to serve as fixturing for the welder, so that no hand alignment is necessary. Since we've started doing that we've gotten huge increases in quality and reduction in time it takes for the welding to be completed.

[Tom Line]

Originally Posted by Cory

They are generally only riveted to serve as fixturing for the welder, so that no hand alignment is necessary. Since we've started doing that we've gotten huge increases in quality and reduction in time it takes for the welding to be completed.

Interesting lesson learned. Maybe we will put it into practice too.

[kevincrispie]

Originally Posted by Cory

They are generally only riveted to serve as fixturing for the welder, so that no hand alignment is necessary. Since we've started doing that we've gotten huge increases in quality and reduction in time it takes for the welding to be completed.

Can't recommend this enough. 971 also generally rivets together assemblies before welding. It allows us to fixture the assembly the way we want before its welded, which makes it much easier for the welder, much easier to transport to the welder's shop, and helps eliminate inconsistencies due to the welding process. We have seem much better results with pre-riveted welded assemblies.

[Seth Mallory]

Originally Posted by kevincrispie

Can't recommend this enough. 971 also generally rivets together assemblies before welding. It allows us to fixture the assembly the way we want before its welded, which makes it much easier for the welder, much easier to transport to the welder's shop, and helps eliminate inconsistencies due to the welding process. We have seem much better results with pre-riveted welded assemblies.

192 also rivets before welding many of the parts.

[sanddrag]

Add 696 in there for one more ditto.

[Spark]

Originally Posted by techhelpbb

As mentioned aluminum welds are typically not as strong as the aluminum itself. Welds can add material so they can add weight. Welds can embrittle material. Welds can cause oxidation. Welds can be deceptive.

Just adding that although welds do weaken metal you have to keep in mind that drilling lots of holes in a piece of metal for rivets or bolts can weaken it as well. Welds, if done RIGHT are the strongest option, but rivets and bolts are faster.