Replacing entire trailer tongue/frame

The trailer I have is too short for my liking plus I can't put my tailgate down while it is hooked up. I thought about adding a piece of tubing to the tongue or re arranging the trailer but the existing tube is an odd ball 2.5x3 tube and is bent pretty good and already has a crappy splice in it. So I will probably be replacing it with 3x3 tube 1/8 wall so all existing brackets will fit my concern is protecting the inside of the tube from rust it will be in fresh water I guess I could try and weld it shut are there any other options?

DONT weld it shut!! Your best bet is to go 3/16" wall tubing and leave the ends open.. Yes it will rust, but it's still going to last 20 years..
You could also spray in some penetrating oil at both ends that will creep down and coat the metal.

Welding it shut will cause castistrophic failure.. Water WILL get in and if it freezes (I'm not sure where you live) will balloon the tube. At work, we use 3/8 wall specially x-rayed steel tubing, and the ice balloons it like nothing.

thread a good length of string/cable/wire through the tube, tie a sponge in the middle. soak sponge in metal primer, use string to pull sponge back and forth. like a dental floss. allow paint to dry and repeat the process a couple of times. it's gonna be messy, possibly won't paint 100% of the tube interior, but offers peace of mind than having bare metal inside the tube.

i know somebody who welded the tube shut and used a bolt to serve as drain plug. filled the inside halfway with used oil, oils slushes around and keeps the metal rust free.

too early to compare which is better, i'd probabaly be too old to care when any rust manages to eat through painted or oil oil soaked metal.......

What if I used a I beam instead? Was thinking 4" 7.7 lbs a ft

mrbacklash said:

What if I used a I beam instead? Was thinking 4" 7.7 lbs a ft

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If you're talking about wood, I wouldn't trust it to be strong enough. I recently extended my tongue by 18" for the same reason. I sleeved over the 2" X 3" tongue with a 4' piece of 2.5" X 3.5" steel tubing, 3/16" thick, and used four 1/2" hardened bolts. Luckily, I have a steel yard near me with all different sizes of tubing, and they cut it to size right away.

Oh not wood, steel only weighs about 1.5 lbs more per foot

mrbacklash said:

What if I used a I beam instead? Was thinking 4" 7.7 lbs a ft

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you can't drill holes on the I beam centerline for the coupler bolts. but i guess you could reposition the mountng bolts off center.

Just use the square tube, but thicker than 1/8" wall.. Your over thinking this...
I have a boat trailer that's 30 years old, yes it's rusty, but no, I'm not worried about it.