Rust inside hollow section steel

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Hi Folks,I have some hollow section rectangular steel with rust inside due to outdoor storage.I can only clean the outside, will it still rust from inside if I build something with it and have it properly sealed off and dry ?
Reply:Rust Never  Sleeps, but it will slow the process down A LOT once you get it in a dry area where the humidity and wetness are reduced.  I have all sorts of things made from metal that is rusty on the inside and I never give it a second thought.  If you are really concerned, you can swab the inside of the pipe down with phosphoric acid which will convert the surface rust into a hard black coating.Miller Syncrowave 350Millermatic 252/ 30A spoolgunMiller Bobcat 225g w/ 3545 spoolgunLincoln PowerArc4000Lincoln 175 Mig  Lincoln 135 Mig Everlast 250EX TigCentury ac/dc 230 amp stickVictor O/AHypertherm 1000 plasma
Reply:If it is completely sealed, the oxygen required to create rust will eventually run out and the corrosion will stop. The depending on the size of the tube, I assume we're talking inches not feet, the amount of oxygen sealed inside is very, very small in terms of the amount of rust it can create.Ian TannerKawasaki KX450 and many other fine tools
Reply:well its a frame 2x6 feetIt might be a bit costly to put rust remover inside.I think I am going to try and slosh some oil inside the frame to try before sealing the frame off.MM 180
Reply:if these are going to be inside, it will take 15 years to rust through. You've already put too much effort into this.Weldanpower 225 G7Ironworkers Local #24
Reply:If the existing welds are really sealed, sloshing some oil in there will make it kinda tuff to seal that final little hole. It's going to want to vaporize & pressurize the tube every time you put a little heat to it. You'll have to sneak up on the final final. I'm with the don't worry about it crowd."The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:sometimes, depending on where it is going you leave a small weephole at the bottom...
Reply:Originally Posted by DougAustinTXRust Never  Sleeps, but it will slow the process down A LOT once you get it in a dry area where the humidity and wetness are reduced.  I have all sorts of things made from metal that is rusty on the inside and I never give it a second thought.  If you are really concerned, you can swab the inside of the pipe down with phosphoric acid which will convert the surface rust into a hard black coating.
Reply:Originally Posted by weldbeadsometimes, depending on where it is going you leave a small weephole at the bottom...
Reply:Originally Posted by lennykwell its a frame 2x6 feetIt might be a bit costly to put rust remover inside.I think I am going to try and slosh some oil inside the frame to try before sealing the frame off.
Reply:You can fill them with grout , I've done it a few times. Use a type that is fluid applicable. You wont use much , or a 4:1 sand cement mix.If it is inside use don't bother.It will make reworking a hassle though.A good guess is better than a bad measurement
Reply:Do not put any chemicals inside the tubes.How would you like to be the welder that encounters those chemicals in the future?Steel rusts at a rate of .002 per year if left exposed to the elements.Don't worry about it.AWS certified welding inspectorAWS certified welder
Reply:btw I by oil I meant I was just going to spray some wd40 or something to just coat the inner rust off.thanks for the replies, I'll seal it off blank.in all reality I can always make another anyway, that's the great thing about being able to do metal fabricatingMM 180
Reply:A product called Tube Seal is used to protect aircraft frames . . .http://www.aircraftspruce.com/catalo...s/tubeseal.phpThe small fill hole can be sealed with a closed-end blind rivet.Dynasty 300DXSmith He/Ar gas mixerMM350PHobart Handler 120Smith LW7, MW5, AW1A