Protect Inside of Steel Tubing From Corrosion

[minuteman62-64]

I've constructed a number of projects using steel tubing. I've pretty well nailed the process of treating, priming and top coating the outside of the tubing to prevent rust/corrosion. However, I've never figured out what, if anything, to do to the inside of the tubing. I've tried spraying some Rustoleum into the innards, but, not sure how effective that is since it can't reach all the way down and there doesn't seem to be a good way to prep the metal in any event.

Anybody got any experience/ideas in this area. Don't worry about it (do nothing)? Other?

 

[MTboatguy]

I've constructed a number of projects using steel tubing. I've pretty well nailed the process of treating, priming and top coating the outside of the tubing to prevent rust/corrosion. However, I've never figured out what, if anything, to do to the inside of the tubing. I've tried spraying some Rustoleum into the innards, but, not sure how effective that is since it can't reach all the way down and there doesn't seem to be a good way to prep the metal in any event.

Anybody got any experience/ideas in this area. Don't worry about it (do nothing)? Other?

You can buy tubing paint wands for doing the inside of tubing, some of the various ones are also designed to do undercoating on cars and trucks.

 

[Scott Danforth]

I have some of the simple tubing paint wands from my automotive restoration days. sort of a bug sprayer with a long flexible hose and a long piece of aluminum with various screw on ends that were simply slit to provide a spray pattern. we also used the garden bug sprayer with some products just to get coverage in areas where a spray gun would never cover.

the other things we did was take a long piece of wire and a shop rag soaked in paint and pull thru tubing to try to coat the inside. not sure how well it worked.

 

[dingbat]

However, I've never figured out what, if anything, to do to the inside of the tubing. I've tried spraying some Rustoleum into the innards, but, not sure how effective that is since it can't reach all the way down and there doesn't seem to be a good way to prep the metal in any event.

Anybody got any experience/ideas in this area. Don't worry about it (do nothing)? Other?

Thus the advent of Hot-Dip Galvanizing

https://www.youtube.com/watch?v=yQUD2vzfgh8

I wouldn't worry about it. Assuming freshwater use only and no blind ends to trap water in the frame. Stagnate (oxygen deprived) water is heck on steel.

Saltwater use, all bets are off.
I'm on my second hot dip axle. First axle lasted ~8 years

 

[minuteman62-64]

Not contemplating a trailer for upcoming project - but, same principles would apply. These tubes will be closed at one end, open at other. Looks like either the "rag on wire" or spraying with an extension or wand would do the trick. Maybe both - degrease w/rag & solvent, then spray.

Thanks, guys.

 

[no704]

Take it to a place that does auto rustproofing, they have a long nozzle that sprays a fine fog into enclosed areas.

 

[sphelps]

If I remember correctly I think Archbuilder treated the inside of trailer tubes for Fuggly somehow ...

 

[Harritwo]

If one end is capped, you can use Fluid Film on the inside, then cap the other end. Fluid Film, Flow Coat etc... are good anti-corrosion.