Welding Sandcasting to Stuctural Tube | Aluminum

Not enough information.

Purpose, strength requirements, specifications, environment.

It can be done.

What kind of "welding" did you have in mind. Or is "joining" by other means OK?

I should add that I have not personally joined these materials.

A little more detail:

-purpose: joint is part of a base for an outdoor lightfixture. (note: after welding, weldment will be powdercoated).

-strength requirements: properly welded joint should be mechanicaly similar to weaker of welded materials (i.e. FEA/hand calcs will be utilized at a later date to validate stresses for applied loads).

-specifications: (I assume you are asking for MIL, ASTM, etc...) none stated at this time.

-environment: outdoor, -10C to 40C, >95% humidity, direct sunlight (note previous comment on coating)

-joining comment: MIG/TIG most likely...others can be evaluated but comment on strength requirement will likely need to be relaxed.

Please keep in mind I didn't include this information originally as I wanted feedback primarily on the practical aspects of the welding of these two materials (not: "Is this the appropriate joining method for the assembly in question?"):

Welding Al is difficult at best. No color change with heat. Welding cast Al is even more difficult, but it is not impossible.

Before you go any farther, wait for some more input from Milo and the other knowledgeable engineers/fabricators.

Good luck.

Your weldment is not impossible by any means. It will require someone who has experience welding A-356 castings though. Talk to your welding supplier for proper rod alloys to use and find a good tig weld shop that has welded castings in the past and go for it.

GA, Spot. Your experience here is a good teacher.

That said,(and going OT here) as I look at this from a manufacturing engineering viewpoint I'd favor a minimum labor approach. I think your idea of a pin is good especially if production is going offshore to Asia or a third world low tech country.

But if you are keeping production here in the USA take a look at adhesives. You can get excellent application help from 3M, Loctite or Lord. You will have to weigh the possible added cost of more aluminum and extra machining cycle time in the cast foot to give sufficient contact support for a well designed adhesive joint. As I mentioned above going offshore can introduce serious logistic problems when it comes to using advanced chemical products like adhesives or finishes that may not be readily available. And you can't always believe the assurances of product availability in remote locations from the sales people at the US manufacturers of this stuff.

Ed Weldon

I agree with Spot! entirely. I have had success with this sort of welding by TIG. Aluminum castings are a common source of dirt problems when welding.

I think using friction stir welding can lead to better results than either TIG or MIG

All:

Thank you!! Great feedback.

I will explore the points mentioned (pin, adhesive, temper, etc.). The geometry makes some of these options less practical but worth a second look. We have done many assemblies using adhesives (Dow 995 and 3M VHB tape projects come to mind). They can do an amazing job when applied correctly.

The rising cost in construction and manufacturing has led to more individuals to seek out cost effect construction and manufacturing materials to produce their products with. One metal found in abundance all over the earth is aluminum. Aluminum (Aluminum Pipes) fits the bill when it comes to being cost effective and applicable in many different ways.