Is Welding Worth It?

[JamesCH95]

This is quite a vague question that depends much on the team. As Andy A said, 95 welds where it makes sense for us. Welding, especially with sheet metal, opens up a lot of design flexibility that we enjoy taking advantage of.

As with any choice in FRC it's not the choice itself that matters, but the execution. We design self-fixturing or easy-to-fixture components, accessible welding locations, and have access to a lot of nice equipment. A team should not expect to get a welder and see success, it will take practice and expertise to do well.

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.

Using a welder safely is no more difficult than using any other piece of shop equipment safely. In fact, a welder is probably safer than many pieces of shop equipment an FRC team might use.

I would not recommend 'sticking only with 6061.' After welding, an aluminum is generally in the "T0" state, in which 5052 has 28ksi UTS and 13ksi YS whereas 6061 has 18ksi UTS and 8ksi YS. This is just one example, there is much research to be done! Some alloys, such as 7005, can age at room temperature back to essentially full strength.

Furthermore, welding in FRC shouldn't be limited to aluminum only. Low alloy steels are easy to weld or braze, offer great strenth:weight ratios, and are not expensive. There are other design considerations for sure, but steel should be 'on the table' when discussing welding.

Originally Posted by marshall

Anyone have suggestions for which epoxy to use for bonding aluminum?

Surface prep is paramount here. Look at the epoxy supplier's suggestions for surface prep. I would recommend 3M DP 190, 420, or 460 for most applications, and Hysol 9309 for critical applications (it has glass beads to arrest crack growth and ensure an optimal bond gap). I would strongly recommend an elevated temperature cure rather than an ambient temperature cure for time and strength reasons.