Rusted steel tubing .. can it be trusted for a stand

I just got a line on some free 2" square mild steel tubing that is 1/8" wall thickness. The only issue is its rusty inside and out. I can grind off the outside, no problem. The inside can likely be sandblasted or hit with some acid, or just pour rustoleum in it. I was thinking if the welds were good would it even matter, as there'd be little oxygen left to let it rust much more. Any metal or welding experts have any thoughts?

Take a piece and cut a section of it in the worst area you can find and check the thickness of the material in the cross section. If the rust seems to only be on the surface, go for it. If the rust seems to have eaten into the thickness of the material then you make the call.

Remember what happened to the Titanic? J/K. Unless it's
been out in the rain the last 5 years or more it would only be surface
rust that would not structurally weaken the stand. You should
tell how deep and pitted by sanding with some 60 or 80 grit
paper on the out and inside with your fingers. Most stands
are way overbuilt anyway to hold up a Armored Money Truck or bus.
Just remember weld shiney steel not half azz cleaned or rust
thinking that flux core will clean the surface for the weld. On old chromoly
aircraft tubing years ago we drilled a small hole and added varnish
that flooded inside of the tubing, drained then sealed with drive pins the holes thus preventing any internal tubing rust. After your all done welding and still have worries about internal rust weld close the leg openings if you have any on top and pour a oil base primer or sealer inside then drain out and save for the rest of the stand tubes. Do this in a bare dirt area as you will make a mess then let it drain as you rotate it around and dry.

BrewBeemer said:

Most stands
are way overbuilt anyway to hold up a Armored Money Truck or bus.

Click to expand...

You say that like it's a bad thing!
Seriously though, go to the hardware store, buy a wire brush that fits into a drill for like $3. Hit the steel with it and you'll quickly know how bad the damage is without cutting your stock. That's was just my approach, but my stand was already a stand when I was testing to see how rusty it was.

Unless the rust is coming off in sheets, or what is referred to as "scale", it is most likely only surface rust and I would not give it a second thought. 2" X 1/8" tube is a lot of steel! Unless it has been exposed to salts, or something that promotes rust, the surface rust aids in protecting the steel below.

Do large flakes come off when probed w/ a pick, or struck w/ a hammer?

How large a system, 5 barrel?

The only hesitation I'd have with that stock is the weight, not the rust, but overbuilding these stands seem to be the norm.

I typically do 20 gallon batches, so it needs to be pretty sturdy. Not too concerned about weight as I don't plan to move it around much, just rolling it out to brew and then back to wherever it will end up living in between brews. Its two states away, I can't easily go check it out but I can ask someone there to try some sandpaper and to hit it with a hammer and see what happens.