Paint advice

[LandyAndy]

Hi People
Once I complete my camper trailer project I will need to re-paint it.
Im very dissapointed with the original paint job.I used Epoxy Killrust with a hardener as a finish coat,loverly black gloss finish.
99% of the trailer is galvanised steel (sheet and RHS).
I scrubbed all the galv with prepsol and steel wool,hit it with etch primer,then red structural primer then the killrust with hardener.
Anywhere exposed to gravel has been blasted back to galv.Where Ive carted firewood has also damaged the paint reasonably easily.
The non exposed areas only need a wirewheel brush where Ive been welding.
Any ideas for the prone areas???
The boat rack is new(Galv) any ideas there to inprove the paint "stick"???
Thanks
Andrew

[CraigE]

As you know I had the same dramas with what was supposed to be a great paint and very expensive, though mine was cold galvanised not gal already. The cold gal was great but the Wattyl top coat and clear was less than satisfactory and chipped fairly easily. Paint prep, mixing, spraying and drying was as per instructions.
Over again I would spend the bit extra and use POR or the Australian equivalent (can not think of its name atm, but has been posted here before).

[Mick_Marsh]

(can not think of its name atm, but has been posted here before)
Penetrol??

[Catmatt]

Hi People
99% of the trailer is galvanised steel (sheet and RHS).
Andrew

Ummmm - If it's been galvanised........why would you want to paint it :confused::confused: Any disturbance to the 'gal' coating (Prepsol, wire brushing etc) will lead you to premature rust/corrosion :confused:

Is it just a preference to paint it rather than have the look of 'gal'??

I'm not being nosey I just wonder why you'd want to paint over an already prepared surface ;)

[LandyAndy]

Want the trailer to match the D2!!!
All the welds would need painting as they would rust.
Andrew

[CraigE]

Penetrol??

No it was actual paint like POR, I think it started with K and is the Australian equivalent.

[jazzaD1]

KBS coatings?

[The ho har's]

gal should be weathered or a good etch, use a two pack paint with the matching undercoat

HoHar

[Vern]

hammertone, cheap easy to paint and tough:)

[CraigE]

KBS coatings?

thars the one. ta;)

[rijidij]

gal should be weathered or a good etch, use a two pack paint with the matching undercoat

HoHar

I've also heard you can wipe new gal clean with vinegar to 'neutralise' it for painting............if you can't wait for weathering.

Does anyone know what the residue is on fresh gal ??

[The ho har's]

yes thinners probably right...

Gal Tubing has an oily type film..thinners/prep-sol/grease will remove it..

ho har

[roverrescue]

Just to clear this thread up.
LandyAndys neat trailer was built using "Duragal" RHS which is different to steel that has been hot dip galvanized post fabrication - despite similar processes.

-Hot dip galvanizing is a very thick surface coating mechanically bonded to the steel surface.

-Duragal is a relatively thin but very even coating applied post seam weld to the steel sections.

Hot dipped gal will stand up to stone chips very well, duragal not so well. And as Andy mentioned where welds are made on the Duragal those weld areas need protection. They rust infront of your eyes up this way!!!

The white residue on freshly hot dip galvanized structures is mostly ash from the zinc tank. As has been mentioned this can be cleaned with a light acid wash like vinegar. There is some contention on whether hot dipped galvanized surfaces should be over-painted. Arguably by its nature a thick hot dip zinc coating is "self healing" which "works" best when not over coated.

To answer the original question, its sounds like you did the right things Andy. Clean, etch prime and overcoat. Essentially the only way to combat stone chips is having a very thick durable coating that is etched into the base metal. So either touch up after a quick clean and put up with stone chips or its time to grind back to metal - reprep and try a different top coat system? Two pack epoxy systems can be very hardy but are still dependent on their ability to etch into the base steel.

Steve

[LandyAndy]

Just to clear this thread up.
LandyAndys neat trailer was built using "Duragal" RHS which is different to steel that has been hot dip galvanized post fabrication - despite similar processes.

-Hot dip galvanizing is a very thick surface coating mechanically bonded to the steel surface.

-Duragal is a relatively thin but very even coating applied post seam weld to the steel sections.

Hot dipped gal will stand up to stone chips very well, duragal not so well. And as Andy mentioned where welds are made on the Duragal those weld areas need protection. They rust infront of your eyes up this way!!!

The white residue on freshly hot dip galvanized structures is mostly ash from the zinc tank. As has been mentioned this can be cleaned with a light acid wash like vinegar. There is some contention on whether hot dipped galvanized surfaces should be over-painted. Arguably by its nature a thick hot dip zinc coating is "self healing" which "works" best when not over coated.

To answer the original question, its sounds like you did the right things Andy. Clean, etch prime and overcoat. Essentially the only way to combat stone chips is having a very thick durable coating that is etched into the base metal. So either touch up after a quick clean and put up with stone chips or its time to grind back to metal - reprep and try a different top coat system? Two pack epoxy systems can be very hardy but are still dependent on their ability to etch into the base steel.

Steve

Thanks Steve
Exactly the sort of info Im looking for.
Thinking areas that were rock blasted,wire wheel go again,may even consider that ute liner style product on the leading faces.
When finished there will be a rock guard on the D2 to help protect it too.
Where Ive been welding I will tread the areas the same then re-spray all the undamaged/protected areas with the top coats again.
Andrew

[Chucaro]

If the trailer was unpainted then I would suggest to give a coat of POT15 primer and when it is tacky then apply the finish coat.
POR15 will never come out but the premier it is not UV reistant.
I have tested it on steel yachts and it is one of the best products available.