Thread: Rusty boat trailer.

So I took my boat off its trailer today to have a look at the condition of it and found a bit of rust. I have no idea if it's rooted or not so would like some advice on how to deal with it. To me it just looks like the rust has just started and has gotten under the galv so it's flaking off. It doesn't seem to be structural yet. If so what are my options now?

Will painting with pe10 or similar give it a bit more life?

Would bolting some anodes into it help?

Box framing with drain holes seems like a really dumb idea for a boat trailer...



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You can get them stripped and regalvanised which is probably the best option.
Or you could seal(weld) all openings which will stop all rust internally and paint or arc spray the outside.

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Painting wont work unless you get back to bright metal as there will be salt impregnating all the corrosion products on tge zinc and steel.
VCs advice is the rolls royce option but fitting a sacrifical magnesium anode could be an option.

Some of those holes will be there from the original galvanising.
They have to be there to allow air to escape from the sections when they are immersed in the molten zinc.
Bad things happen otherwise.
Do you know someone who could sandblast it cheaply? At least enough to get the corrosion out then paint it with good stuff or otherwise see if the galvanisers can re-dip it. I think they have to put it in a stripping bath first to take the old stuff off. Not sure about it getting rid of rust.
Still looks pretty solid-maybe a quick buff back with the grinder and hit it with paint. Hard to do the inside bits though.

Thanks guys. @berg243 any suggestions on a top coat product

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A mate had his wood business trailer painted with inorganic paint (what ever that is) 8+ years ago. While not new, its in bloody good nic and done a shite load of work!

Inorganic zinc is just a paint with lots of metallic zinc. Works OK. I have tried PA10 which I found pretty average, and POR 15 which is great but my favorite is Hammerite (easier to use than POR15). It seems to create a glass like impermeable coating.
Stripping and re galvanizing is a big job but probably the best solution long term.

Take it to the Galv Plant in Palmerston they would take a look for you and can advise what to do. I don't think they stick large Galv items in the Acid anymore so you would have to get it sand blasted which is better for the Zink to stick to anyway. I worked at HB Galv for a couple of years and the boss said the best thing to build boat trailers out of was C Channel and Angle.

Originally Posted by Fireflite

A mate had his wood business trailer painted with inorganic paint (what ever that is) 8+ years ago. While not new, its in bloody good nic and done a shite load of work!

It will have been inorganic zinc silicate, basically the next best thing to galvanizing. Very hard for a diy to use and needs to go on a sandblasted surface ideally within 2 hours of blasting.
To be effective zinc metal containing paints must be in intimate contact with the steel surface for them to work. Putting them onto rusted or painted surfaces is a waste of time and money.

most rusty boat trailer's i have repaired have rusted from the inside-out as the salt sit inside the tubes and can't be washed out. by the time it is visible it's normally rusted quite bad sorry!

Originally Posted by ONYVA

most rusty boat trailer's i have repaired have rusted from the inside-out as the salt sit inside the tubes and can't be washed out. by the time it is visible it's normally rusted quite bad sorry!

Yeah I'm looking at new Trailers to compare the cost effectiveness of all options!

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Originally Posted by ONYVA

most rusty boat trailer's i have repaired have rusted from the inside-out as the salt sit inside the tubes and can't be washed out. by the time it is visible it's normally rusted quite bad sorry!

Originally Posted by Wildman

Yeah I'm looking at new Trailers to compare the cost effectiveness of all options!

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That is often my experience too that they are rusted out from the inside.....tho yours looks to be from the photos provided still structurally sound....that means that if you can effectively halt the rust both on the inside and outside for another ten to 15 years you are on a win.

Halting the rust on the inside is Key to any successful long term use, steel will not/chemically cannot rust without exposure to oxygen. TOTAL sealing is usually the easiest option IME(here in Nelson with no hot dip service...your mileage may differ) but it means all your cables need to run on the outside and not even a pop rivet can be drilled into the members or it will let the atmosphere in to rust it.

You are well positioned to save the trailer going on the pictures.

Options as I see it going on longevity of repair not cost.

Option#1

Strip lights rollers springs axle hubs etc and get it acid stripped and re-galvanized.....cannot advise cost but best long term solution, if done properly it will be effectively a new trailer good for 10-15y (caveat is that the trailer is suitably strong already and has had no and I mean zero cracking issues. )

Option # 2 seal the entire trailer and blast and arc spray any surface rust, tricky bit here is it has to be absolutely sealed.....and galv and rust is a bitch to weld and seal so ideally you want a well qualified mate who works for beer or Venison.

I often remove and replace the two cross-members on smaller (less than 6m boats) trailers, I usually cut the crossmember 100mm away from the outside members so I dont burn off the galv inside the side runners then once the new steel cross-members are in carefully and slowly fill in the galv venting holes so the cross members are fully sealed and arc sprayed but the side runners are still open for flushing, depending on the condition of the trailer the MAXIMUM I would tell the customer it would last is 5 years as if the cross members are gone the sides are not far behind generally.

Option #3

Blast and arc spray outside spots of rust, very cheap and effective and arc spray has an anode effect just like galv and surprisingly a anode !....however it will only slow inside rusting.

I am no paint expert so will leave those options to others more qualified but it must be very difficult to prep and paint the inside of a RHS.

Option #4
Buy a wire buff wheel for your 5" grinder and clean up external rust then paint with a generic Zinc spray can of goodness.....this is the give you a couple of years to save for a new trailer option but you will have to keep at it.

When I made my trailer cage I used heavier than usual box section but drilled strategic holes big enough that when it was hot dipped the insides of the box got the treatment. These holes were located where I wanted to bolt stuff on or bolt the cage to the trailer. Worked a treat.

Originally Posted by gadgetman

When I made my trailer cage I used heavier than usual box section but drilled strategic holes big enough that when it was hot dipped the insides of the box got the treatment. These holes were located where I wanted to bolt stuff on or bolt the cage to the trailer. Worked a treat.

They wont hot dip at all if you dont have sizable holes in both ends of a member.....makes big bangs! think dry ice in drink bottle but spraying 500dec c molten Zinc over anyone near.

Originally Posted by veitnamcam

They wont hot dip at all if you dont have sizable holes in both ends of a member.....makes big bangs! think dry ice in drink bottle but spraying 500dec c molten Zinc over anyone near.

And they were not keen on too much rust either. Mine was pretty clean.