How to stiffen 1/2" aluminum tube?

[Myka]

Originally Posted by Reef Pilot

That's true, but humidity is enough to start corrosion. With aircraft we use zinc chromate epoxy for all joints which seals against moisture, and is also a glue for extra strength. But you can't buy that stuff in a regular hardware store.

So is it a reasonable solution to seal the steel away from the aluminum then?

Not sure how heavy the fixture is, but bear in mind this only strengthens the bent tube area, and if your tube size isn't large enough, you could still get bending and flex with the weight.

About 18 lbs.

If you need more strength overall, you can make the cut tubes (or gusset) longer. A larger gusset can also be rounded on the outboard side towards the middle to provide more clearance if necessary (and it will look prettier). For the gussets, I would use .040" or .060 sheet pieces. Your local metal shop usually have scrap bins, and should let you pick out small pieces at no cost. Oh, and use T6 6061 aluminum for superior corrosion resistance.

I really don't want a gusset. You mean something like this, right?