What primer to use for caravan exterior?

[LizzieCro]

Evening All,

I have a bit of an issue as I start the prep work on the exterior of my current onsite caravan. The previous owner has painted the van with, (I'm told) some sort of specialty paint for aluminium. I'm not convinced it's water based paint, as it appears unlike the finish water based paints provide. I have no way to find out what paint he used. The paint job was pretty dodgy so I'll have to sand the whole van smooth (but not back to metal), which will remove the gloss finish, and perhaps create some tooth for the new topcoats. Has anyone found a good, reliable primer that will allow water based products to adhere to oil based on exterior jobs? I'm wondering if the Dulux Precision Maximum Strength Adhesion Primer would do the job? I was hoping to avoid priming and just use Dulux Weathershield Maxiflex as my top coats, but it looks like a primer is inevitable. I'd be really grateful if someone could offer any advice, please.

Thanks very much.

[MitchellMc]

Hi @LizzieCro,

It sounds like there's a good possibility that automotive paint was used on the caravan. If that is the case, then it excludes the use of standard products such as the Dulux Precision Maximum Adhesion Primer. I've spoken with Dulux about their range of Metalshield products, but once again, they are not suitable for unknown paint. You'll need to stick with Automotive paints if that is what was used.

Let me tag @twocutekelpies for their thoughts.

Please let me know if you have any questions.

Mitchell

[LizzieCro]

Thanks for doing that Mitchell. I appreciate it very much. I know it wasn’t automotive paint as the previous owner’s brother confirmed that. It also lacks the gloss of those paints. Whatever it was was specifically for aluminium. A bit unnecessary though as the van had previously been painted twice! 

[MitchellMc]

It's a bit of a conundrum, @LizzieCro. As far as I'm aware, the only specialty paints for aluminium are those for specialised purposes, such as automotive paint. There are primers suitable for aluminium, but then the top coats are just epoxy enamels.

You could certainly try the Max Adhesion, but given the unknowns, it's not possible to really gauge how effective it would be, and its use would be at your own risk.

Mitchell

[LizzieCro]

It’s definitely not an epoxy enamel, far too dull for that. It looks dense enough to be oil based semi-gloss. I might try the ‘rub with metho’ technique and see what is proven. I doubt the previous owner would have wanted to use oil-based paint but you never know.

[LizzieCro]

Back again @MitchellMc .

New information just to hand! I managed to track down the bloke who painted the van, and it's nothing special at all, just, as it appeared, an oil based exterior metal paint. At least I know what I'm dealing with. My situation is that I'm going to have to paint the caravan towards the end of May-early June, when temp's are low. The van is situated near an ocean inlet, and is on the south side, so the area I have to paint will be in shade the entire time. My concern using oil based primer is that my drying time will extend into darkness, when the dew falls, and I could end up with a real mess. Cold temp's won't help at all. Do you know of any product/primer I could use which has a quicker drying time, but would be compatible with the original oil based topcoat, plus my intended water based Dulux Weathershield Maxiflex? I've used ESP on many, many things, including mirrors, laminates, and tiles, with great effect, but never used it for exteriors. Do you think that might work? Thanks Mitchell.

[MitchellMc]

Hi @LizzieCro,

Dulux Weathershield is a flexible product, and the oil-based enamel metal paint is not. Dulux is very clear that they do not recommend the Weathershield over the current paint. It's one of those things that hasn't been tested, so there's no information for me or them to go with.

I might have a solution, though. If you sand back to a sound, painted surface, you can use White Knight 1L Rust Guard Quick Dry SLS Etch Primer Paint and, when dry, White Knight Rust Guard. The primer is solvent-based and quick-drying, and the paint is water-based and has a similar quick-drying nature.

Mitchell

[LizzieCro]

Thanks @MitchellMc . I agree, and was actually thinking of using those products as I've used them on a previous onsite caravan. I found the Etch Primer terrible to use from an application point of view as it dried so quickly, but as I'm in cooler weather and shade, it mightn't be too bad this time. I used the Rust Guard top coat for the upper part of the van, but Dulux Weathershield Maxiflex on the lower. It's now 3 years later and both topcoats have held up really well. Looks like it's my best bet, (only bet!). I will be sanding the entire van first anyway as the paint job is full of runs and brushstrokes. Fingers crossed all will be well! Thanks so much for your help and advice, Mitchell, which is very much appreciated.

Cheers, Liz.

[MitchellMc]

Good luck @LizzieCro. Please reach out again if you have further questions or get stuck.

Mitchell