Ok - my rails are actually air tight...now what to do?

[ozscott]

My trailer chassis rails - RHS - are air tight. To the point where they hold pressure from the air compressor - the ends are welded and the bolts for draining and filling of oil or similar have nylon washers and the 5mm wall thickness gives a good hold on the bolts. So I am going to fill with fisholene - a couple of litres per rail. But my question is, lets assume with an air fitting screwed in (like a tyre valve for eg) they could hold pressure pretty much indefinately - ie good welding! - would a small amount of positve pressure help keep condensation from forming and therefore make it a water free zone? Weird hey?

Cheers

[Grim Reefer 750]

Hi Ozscott,
If you pump compressed air inside the box section you are actually adding moisture anyway so I don't see how It will help. Just use a liquid rust preventative, which ever product you choose. I also have sealed all cross members on my trailer and fitted 3/8 brass plugs.

Cheers Don.

[Mattya]

Not compressed air, but a vacuum pump could be the go. Suck out all the air & moisture. If you were really pedantic, you could then fill with nitrogen..

[tunaticer]

I would drive around with the trailer for 20km or so to slosh that fishoilene around then drain it and leave the bungs out for a week. then seal it up again and use it as normal. If you don't air the fishoilene it will not set effectively, you need to evaporate off the hydrocarbons for it to set.
I would not be positively pressurising the trailer, apart from introducing moisture, it could also cause premature breaking by adding stresses to flat surfaces.

[ozscott]

Thanks gents. I will do the drive and drain thing. Let it sit airing and then do the same thing again in a few months time etc, until there is a nice thick coating. I suppose leaving a little in there sloshing around after the initial drying wouldnt hurt either.

Cheers

[captain rednut]

mines full of sump oil and is 20 years old and like brand new. that solves the moisture problem.

[TheRealAndy]

My trailer chassis rails - RHS - are air tight. To the point where they hold pressure from the air compressor - the ends are welded and the bolts for draining and filling of oil or similar have nylon washers and the 5mm wall thickness gives a good hold on the bolts. So I am going to fill with fisholene - a couple of litres per rail. But my question is, lets assume with an air fitting screwed in (like a tyre valve for eg) they could hold pressure pretty much indefinately - ie good welding! - would a small amount of positve pressure help keep condensation from forming and therefore make it a water free zone? Weird hey?

Cheers

In the commercial world they fill structures with nitrogen and I think argon is also used, but not 100% sure about that. The Goodwill bridge from QUT to Maritime museum is one such structure.

[ozscott]

mines full of sump oil and is 20 years old and like brand new. that solves the moisture problem.

When you say full do you mean chockers or just a few litres sloshing around. I was going to use oil but decided on fisholine - maybe I will use fisholine until dry and coated and then use oil...decisions decisions.

cheers

[myusernam]

fisholine! dirty old sump oil is free and will do just as good a job (probably beter) just get some used oil for free

[wirlybird]

mines full of sump oil and is 20 years old and like brand new. that solves the moisture problem.

ha ha same as my one

[Jarrah Jack]

If you fill it with helium it may even become a ufo.

I don't think you would need to worry about condensation that much, the oil will give a nice protective coating.

[fisho64]

mines full of sump oil and is 20 years old and like brand new. that solves the moisture problem.

out of curiousity-how would you know if the inside is like brand new?
Never liked RHS trailer chassis but I see the biggest advantage of this (oil filled) as being-if you get a crack in the chassis you will know straight away due to the leak.

[ozscott]

Rhs with inspection bungs if all properly sealed is a great setup.

Cheers

[fisho64]

I beam with no bungs even better!

[banksmister]

Was told about a person with a ski boat that integrated fuel tanks on his trailer.
Great idea until he emptied the tanks and tried to load the boat.
Yep the trailer floated.

[liltuffy]

Doesn't sump oil turn acidic ????

Just sayin

Craig

[ozscott]

I wouldn't use it...fresh cheap oil is cheap and non-acidic. ..I would leave that for treating fence posts but clearly its worked for some as posted above.

Cheers