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View Full Version : Maintaining the Gal on a Trailer



smclaren
07-04-2011, 08:31 PM
Howdy

My trailer is getting old ... it's still in good nick but I am noticing surface rust and general breakdown of the gal ... particularly in the low spots on the frame.

Apart from the after-use fresh water hose down ... what can be done to the gal to maximise the life of the trailer ? Any additives, paints etc to be applied ?

Thanks.

Dan5
07-04-2011, 08:42 PM
Mate try some Lanolin.........

I lano'd my boat trailer in 07.....3 times in the first week or so........just last week i citra forced it {degreaser) and hit it with a high pressure blaster and it came up looking new.Not just clean but shiny gal new.

The trailer has been used in almost exclusivly saltwater and just rinsed with fresh after wards.........sometimes the trailer will get multiple salt dunkings for a week or more before a freshwater rinse.

The only place i did not lano was the tow hitch and chain and it's the only spot i have surface corrosion.

Treat it with lano you have nothing to lose.

Dan

TheRealAndy
07-04-2011, 08:45 PM
Drown it in tectyl 506. Ducks nuts. Your local industrial coatings supplier should be able to sell it to you in tins. Super cheap sells spray cans, but its dear as poison.

Dan5
07-04-2011, 08:48 PM
Yeah forgot to mention........the black steel wheel studs were still black.........not one spec of even surface corrosion on them after 3 odd years.

pretty impresive stuff i thought.

oldboot
07-04-2011, 10:23 PM
I use this process on the young BIL's trailer nearly 10 years ago and it is still holding up well.

I've just finished and sold my old trailer after doing this,too..it looks great.

dismantle and strip all the bits off the trailer.

use a flap disk followed by a wire brush on a grinder to remove any light rust, or chalky gal all back to bright sound material.

A soft wire brush on a bench grinder is great for cleaning the smaller parts.

You might have to get more agressive with heavy rust.

do any welding required.

If you have an oxy set or even an LPG flame, work over any rusty sections or chalky gal after the flap disk......it drys out the oxides and makes them much easier to get off.

Any bolts that wont come undone... hit them with the oxy...and don't be timid.....if it still wont come out after you have heated the nut and bolt red......heat it up and try while it is hot.

scrub the whole thing and all the parts with thinners

touch up any bare steel with a good quality cold gal ( the Galmet is good and expensive but it holds up).

Then go over the whole thing and every part with Galmet Duragal this is a paint intended for overcoating and touching up gal and zincalume type finishes.

as you assemble coat every nut, bolt and screw and any two metal surfaces that are pressed together with a marine grease.

when the whole thing is assembled...wipe off all the screw threads and bolt and nutheads and spray them with duragal too.

remember, galvanising is a sacrificial coating, a good paint job will make it last a hell of a lot longer.

once the paint is well off, get up all the channels and crossmembers with lanolin spray cut with a bit of white spirit to make it flow.
I use a length of microirrigation grafted to a trigger bottle....it will get most places........don't park it on a driveway you care about for a few hours after this.

The gal on my new trailer has just about "gone off", I intend stripping that and spraying it with duragal.

The pictures show you what can be achieved

cheers

Noelm
08-04-2011, 09:10 AM
Galvanising will last for ages IF it is painted/coated/fishoiled/whatever before it goes near salt water, once rust has started, it is near impossible to stop, on steel that is just out in the weather, cold gal and paints are OK, but to be dipped in and out of salt water is a whole different ball game! it needs to be properly galvanised, and painted with some sort of protective coating, I once used some clear stuff that had a name like "imperite" or close to that, when I got the trailer, and it was still shiny when I sold the rig nearly 5 years later.

oldboot
08-04-2011, 11:07 AM
Again, remember galvanising is a sacrificial coating and it will eventualy be consumed if it is not given some other protection and religated to secondary protection.

Of late the galvanising on many of the new trailers is a bit light on and not real flash..so ya cant rely on it alone.

People have far too much confidence in galvanising.

My sisters husband ( the large BIL) built his own boat trailer many years ago, it has only ever been painted and lives outside, at one time it would have been in the water 2 or 3 times a week, there is a conspicuous absence of rust in the frame.

The problem with rust, is most people are not prepared to do what it takes to treat it or prevent it.

The number 1 cure for rust it to remove it all, and soo many people are looking for a short cut......painting over rust is one that simply does not last.

The oxy trreatment is 1 short cut I have found to work, heating the rust, even scale, dries it out, some of it will pop off, some has to be mechanicaly removed..some you just have to keep trying till you have removed it all.

The guards on the young BIL's trailer had scale comming off in sheets, we heated and scrubbed till the metal was bright then cold gal and Duragal.....to this day there is no sign of rust and that is over 9 years now.

The problem with a lot of the oil, grease and tar bassed products is that they have to be reapplied, a good paint job will last decades......many untreated trailers will not last that long from new.

cheers

Noelm
08-04-2011, 11:43 AM
fully agree on the galvanising on some new mas produced trailers, I reckon it must take great skill to get it so thin! a proper galvanising place will do a far better job, but it will cost you, my last trailer, made out of square tube section, was sand blasted, the painted with some sort of industrial zinc rich paint, the ends were blocked with plastic end caps and silicon, then the tubes were almost filled with used sump oil via a hole left in the top, and plugged when oil was in, and to this day it is still good, mind you, I reckon a trailer made out of some sort of I beam or very heavy angle would be heaps better than square/rectangular tube!

oldboot
08-04-2011, 11:48 AM
The issue is that any closed section, square, rectangular or circular will have a much higher strength to weight ratio than an open section, angle T or I section.

with a tube bassed chasis, still the best thing is big drain holes and lanolin spray the whole interious length.

cheers

Jarrah Jack
08-04-2011, 12:03 PM
Take it into a gal place and get it regaled. It will cost twice as much as painting. You could then treat it with tectyl and it will last and last.

Correct me if I'm wrong Oldboot and Noel but I think the gal places can acid dip a trailer first to clean it all up ready for the gal dip. When I last used the system I got all the bits sandblasted first.

cormorant
08-04-2011, 12:40 PM
To regal a trailer I have always been told they actually blast / acid all the old gal off then do various dips, caustic , acid and then regal from scratch. I may have been led up the garden path. Basially I have been told you can't gal over old gal. The surface treatments and cleanness of the metal along with the care of the operator determin the end quiality.

As for galmet and many other paints that are only as good as their preparation. When I had a trailer regalled they told me not to bother touching up with galmet as it was Ok on a fence post but not designed for salt water and trailers. They did lots of industrial marine work. They suggested some fancy watyl paint , in silver colour if you liked, and proper preparation on the bits I was bolting on that were not gal. They were right. Bluntly the goldgal I had already done on some bits was stuffed after 2 years and reapplication just made it pretty but the proper coating lasted and lasted as it was totally impervious to water so no moisture got to underlying metal.

Maybe someone here in the paint profession or metalwork could clarify the story as we all see the coatings on bridge pylons etc and they last for years in a hell of a environment and have that paint with small silver looking particles in it.

Be interested to know if it would be worth doing a paint over a gal goating to ensure a longer life from new? No idea how that would work as we all know gal works buy getting that thin coat of oxidisation so not sure how it goes under paint. I know on zincalume they overcoat with a special epoxy at teh factory.

Guess teh simple answer is to go ally and watch the welds or stress around bolt holes.?

Noelm
08-04-2011, 01:25 PM
depends on how good the metal is when you are getting it galvaised as to how it is treated, new steel is just acid dipped and cleaned to bright shiny, and dipped in zinc, and moved about to make sure all the nooks and crannies are covered, rusted or painted steel needs to be sand blasted first, then the acid process is the same as for new, previously galvanised steel is acid dipped and the zinc reclaimed, however if it is badly rusted, they will just sand blast all the old gal away and start again. Remember, box section steel that is badly rusted will not be sand blasted internally, and as such, the zinc will not stick! so some sort of paint/oil/whatever will need to be employed as well.

Noelm
08-04-2011, 01:34 PM
Just a couple of tips for anyone thinking of getting their trailer redone (from someone who has been caught out plenty of times) first off, pull everything to bits, the galvanising place will not undo a nut and bolt, it will get galvanised along with everything else, make 100% sure, all your parts have your numbered tags wired to them, the galvanising places do not keep stuff together and it is no fun looking through the yard for things that could be yours, any chain welded to the trailer will be a solid lump when you get it back, oxy will melt the zinc and you will need to hold the links seperated untill it cools a bit, roller pins will no longer have holes in them for split pins, lots of stuff will get bent out of shape, like gaurds and other thinnner bits, roller pins will no longer fit in the roller brackets, while you are getting it done, get a few anchors and stuff done too, the price will be bugger all as a "job lot", I am sure there is otherstuff as well, but those are the things that have caused me grief over the years.

cormorant
08-04-2011, 02:36 PM
The acid dip I was told it was left in till all the old gal was off . Basically can't get new gal to stick over old gal.??? Caustic baths was to clear old paint and oils so acid works inside rails.??

I once asked if they could "double dip" and they laughed so hard and said they could double dip my wallet but gal will only stick / meld to fresh metal not to a already galled coating. I chose not to have my wallet double dipped!!;D

The temperatures they use and metal in the dipping tank is what creates the thickness and bond and that is why the OS gal stuff can either be good or absolute thin crap.

Anyone know anything about the "plasma " coatings where preheated bit of metal is coated witha hot plasma? Wondering if it could be used on triler repairs to get a propper gal finish again?


Like noel I have learnt to make sure there is lots of holes in corners and no slag left on stuff going for gal because as much as they jiggle in the bath if there is air in a corner it just won't bond and coat then the rust starts. All thin metal distorts at those temps so I always have all the stuff as bolt on not welded or heavier guage and fully welded and small items weld small washers on as a point that the can put wire through for dipping. Doesn't matter if small washer rusts later on.

Noelm
08-04-2011, 02:45 PM
the gal place near me will not accept anything for coating if it is painted or rusted, they insist on sand blasting, new lightly rusted steel is OK, the acid dip will clean it off, but proper rust, no way, so in that case the insides of rusted tubes will not get cleaned, and therefore will not have a zinc coating on them, everything needs to have holes for sure, they dangle the frame on a crane sort of thing, lower it in the molten zinc and jiggle it a bit, then drop it and turn it around to get other parts covered, remember you pay for galvanising by weight, so if you get a pile of zinc in corners, then you wallet will get double dipped whether you like it or not,

cormorant
08-04-2011, 03:08 PM
I've been charged by the weight of of the steel going in as far as I know and they ask if it is a frame or flat steel etc so they work out the "rate"as they know how much a coating weighs at XX thickness. About the energy to get the mass of steel hot enough to coat . From experience I think they know the averages of surface areas and mass for trailers and stuff. . I don't think they have weighed my stuff afterwards and done like a weighbridge ticket. Jeeze that would be time consuming but I guess for production stuff they would do test samples to make sure they are charging correctly . They know how much fresh zinc tehy are putting in the pot all the time.

I honestly don't know if there is 10kg 20kg or 50kg of gal on my trailer? I'm guessing under 20 kg on a duel axle as it in the end is a pretty thin coating it is just that it bonds so well to get the protection.

indy
08-04-2011, 04:42 PM
Buy a big tub of grease and a couple of those lovely pink washing up gloves and go nuts, guarantee your trailer wont rust. If you can after you do this leave your trailer out in the sun with the boat off so it goes hardish will take some time.


Cheap and buy far the best

Squidlet
08-04-2011, 05:46 PM
Mate try some Lanolin.........

I lano'd my boat trailer in 07.....3 times in the first week or so........just last week i citra forced it {degreaser) and hit it with a high pressure blaster and it came up looking new.Not just clean but shiny gal new.

The trailer has been used in almost exclusivly saltwater and just rinsed with fresh after wards.........sometimes the trailer will get multiple salt dunkings for a week or more before a freshwater rinse.

The only place i did not lano was the tow hitch and chain and it's the only spot i have surface corrosion.

Treat it with lano you have nothing to lose.

Dan


DAn where can we get that up here in darwin?
Cheer's Squid!

finga
08-04-2011, 06:07 PM
DAn where can we get that up here in darwin?
Cheer's Squid!
Just ask any industrial suppliers like a nut and bolt shop.
Lanolin is the bees knees for stuff like that.
It actually softens under heat and rejuvenates it's skin if there has been a scratch or something like that.
Normal old grease isn't that far behind and after the grease effort go for a drive up the dustiest road you can find to get a layer of dirt on the trailer.
A sh!tty old trailer isn't what thieves like when a nice shiny one is available right next door. :)
The tiny tinny trailer was made in 1972 and it's like new under the grease crud. ;D

siegfried
08-04-2011, 09:07 PM
Clean him up spray him with Penetrol