Aeronaut Queen Painting

[andrew lillywhiteParticipant @andrewlillywhite51573]

Hi, I am looking for some advice on below the waterline painting of an Aeronaut Queen. I have put 10 coats of exterior varnish on the upper sections of the boat and am now starting on below the waterline.
This area has had two coats of sand sealer, rubbed down and a further two coats of waterbased varnish, purely to seal it. I am looking to paint below the waterline with a primer and then white top coat. After all white is applied, will put on four coats of polyurethane varnish.
My question is really, what type of primer and white top coat should I use that wont react with either the waterbased varnished used as sealer and also the polyurethane top coats of varnish.
Any guidance would be greatly appreciated

[andrew lillywhiteParticipant @andrewlillywhite51573]

what paint for under waterline

[Dave MilbournParticipant @davemilbourn48782]

To be safe you must avoid anything which is solvent-based. I'd use matt white Humbrol enamel as a base coat and the gloss as the top coat. Mattias 'Banjoman' uses a water-based acrylic – Vallejo Premium RC paints – which I haven't tried [see his Moonbeam thread] which might be as good or even better.

I would also advise against using a polyurethane clear varnish over white. It will yellow very quickly unless you buy a proper yacht varnish (International) but these are a swine to apply with a spray and even worse with a brush – that's if you want to avoid brush marks.

Good luck!

Dave M

[andrew lillywhiteParticipant @andrewlillywhite51573]

Hi Dave, thanks for coming back and the advice.

Poly varnish is international so should be ok.

Will have to brush the white as no spray facilities at present, just need to work out how much base and top coat I will need

[Colin BishopModerator @colinbishop34627]

Just to amplify Dave's comments above.

He is right that you should not put any sort of varnish over white, it will inevitably discolour it. External grade polyurethane and also yacht varnish contain tinted UV inhibitors to protect the surface which is why they look like syrup when you open the tin. Interior grade polyurethane does not contain these and is therefore more transparent although it will still give a slightly yellowish tint to the surface to which it is applied which is particularly noticeable over lighter colours and white although not so much over mid tones upwards. It is OK to use the interior variety on model boats unless they will be spending most of their time in strong sunlight or bright daylight conditions and most of course don't.

To get a decent white surface you MUST use an appropriate white topcoat and not apply anything over it. Humbrol gloss enamel should be OK as Dave says, but if you want a really good finish try International Toplac Snow White.

**LINK**

This is a top class brilliant white yacht enamel. Yes, it is expensive for a model but you can use the rest of it around the house inside and out where it will last twice as long as the stuff you can buy in B&Q and Homebase etc. I insisted that the professional painter who recently did some external redecorations on my house used it and although doubtful at first he was amazed at its quality compared to the paint he normally used. And if it lasts up to twice as long then it is cheaper in the long run too!

Colin

[andrew lillywhiteParticipant @andrewlillywhite51573]

Hi Colin, thanks for the detailed reply.

I hopefully deduce correctly then, white yacht enamel is fine to go on top of water based varnish, with suitable base coat. If I do wish to varnish over top coat, then water based varnish is fine. Does it make any difference on type of enamel.

Thanks again

[BanjomanParticipant @banjoman]

Hello Andrew,

As Dave M says, I use a range of acrylic model paints and associated products called Vallejo Premium RC (**LINK**). As would, I am sure, be true for any kind of paint, they have both strong and weak points.

More specifically, they are primarily intended for airbrush application, which is also how I mostly use them. They can certainly be applied with a brush, too, and I have decent experiences of this, too, albeit much more limited than my airbrush useage. They do not come in rattle cans.

With the airbrush, they can be applied straight out of the bottle with any needle size above 0.4, and have splendid covering and self-equalizing properties. From my limited experience of brush application, I would also say that they go on very smoothly that way too, and will self-equalize quite nicely. However, I have never really tried painting any large, flat surface like a hull with a brush, so cannot really review them from that point of view. Based on the smaller and touch-up work that I have done with a brush, however, I would say I think it should be feasible to get a nice result that way also on larger surfaces, if care is taken.

They have a flat white primer paint that is a very good primer, and a gloss white top coat paint that are both nice enough to work with. The pigments in the gloss white are perhaps not quite as strong as those in other colours (their bright red for instance is fantastic, and the black outstanding), and so might require a few more coats for good coverage, but otherwise should be fine. If applied with an airbrush, I have found the primer to be a tad on the sticky side, compared to the top coat paints, with a fairly rigourous cleaning schema required to stop the nozzle from clogging, but then again, sticky is exactly what a primer should be, so that sort of goes with the territory.

I also use the clear polyurethane varnishes in the Premium RC-series, and so far haven't noticed any yellowing, but then again I've yet to paint any such surface as the bottom of a hull all white, so cannot really say one way or the other if there is such a problem with this particular varnish.

These paints are primarily intended for r/c car bodies, and so are not often found in standard model or hobby shops. They are however available from i.a. Amazon; both the white primer (**LINK**) and the gloss white (**LINK**). They are also carried by Everything Airbrush (**LINK**) and even by a Purveyor to HM The Queen (**LINK**)! Further googling would, I'm sure, throw up yet more vendors in and out of the UK.

Two more words of caution, should you decide to give them a try:

1. Always, always, always do a test piece first of the combination of paints and products you intend to use, both to ensure compatibility and (if one component is a new aquaintance) to familiarise yourself with their behaviour.

2. Where solvent-based paints dry from the inside out and thus, when dry to the touch, are basically dry all the way through, acrylics dry from the outside in and thus, while dry to the touch, may still be partially wet underneath, and thus unstable or not yet at full strength, which can lead to nasty surprises when e.g. applying masking tape to a newly painted area. The Vallejo Premkum RC-piants when airbrushed will be dry to a light touch within minutes but, depending on the number coats and their thickness, as well as room temperature and humidity, will only be fully cured after between, say, 48 and 72 hours.

Personally, I very much like these paints — not least, perhaps, because I am now familiar with them and their behaviour — and for someone looking to try summat new or having no established range of favourite paints, I would definitely recommend them for a trial. Whether or not you would like them, I obviously cannot say; the only way to find that out would be to try them for yourself.

Also, if you are lucky enough to have trusty, local hobby store that carries e.g. Humbrols, the convenience of being able to pop in for another tin might argue against the inconvenience of having to send off for paints; if, on the other hand, you would have to do so anyway, well …

Mattias

[BanjomanParticipant @banjoman]

I hasten to add that my choice of the Vallejo paints is heavilly influenced by the fact that I do almost all my model painting with an airbrush, which imposes certain restrictions on the choice of paints. For example, the paint must be able to pass through an airbrush nozzle, and therefore cannot be too thick.

For brush application, other rules apply, and I would be inclined to think that the yacht paint recommended by Colin would be a better bet by at least a short mile.

Mattias

[Colin BishopModerator @colinbishop34627]

Andrew,

Using water based varnish to seal the hull was not really the best idea as varnish is intended as a top coat and not to be overcoated. You could get away with traditional varnish to some extent as the solvent penetrates and bonds into the wood in a way that water based versions cannot.

So firstly a lot will depend on how well your existing water based varnish has bonded to the hull. Assuming that it has then you will need to rub down the surface before applying a general purpose primer followed by a paint topcoat.

Applying a water based varnish over a top coat paint finishe is definitely NOT advisable as the water based finish is unlikely to bond to the surface and will simply form a film over it which will then be prone to peeling off or blooming a milky white if it is damaged and water gets underneath it. Believe me I know!

Generally speaking it is not a good idea to use paint and varnishes together on the same surface as they are intended for different purposes and the results can be unpredictable. I use interior polyurethane to seal over Halfords red oxide primer for underwater sections of my hulls and that works well as the polyurethane bonds well to the primer.

In fact the polyurethane varnish can usually be used fairly safely over most finishes as it bonds well and rarely reacts with a well dried surface but nothing is guaranteed. The downside, as I have said is that it will darken or tint the underlying surface to some extent.

Mixing incompatible surface finishes is probably the most common cause of model boat painting problems and crops up again and again on the internet forums. One essential way of mitigating the potential grief and extra work is to try things out on test pieces first before applying anything to your prized masterpiece!

PS: re the Yacht enamel, it does brush on very well indeed to give a smooth surface.

Colin

Edited By Colin Bishop, Website Editor on 26/01/2017 11:02:23

[andrew lillywhiteParticipant @andrewlillywhite51573]

Hi all, and again thanks for the comprehensive answers.

As I cant airbrush yet, will have to go with the brush, but thanks Mattias on the detailed explanation, will be considering those paints when I get an airbrush

Think I will be on yacht enamel, which I can apply after I have rubbed down the hull, water based varnish has adhered extremely well, but do now realise not my best decision.

So If I go for yacht enamel, I just need then base and gloss top coat and not varnish over the top. I assume enamel will be scuff resistant.

Thanks again

[Ray Wood 3Participant @raywood3]

Hi Andrew

I use Humbrol Enamels for most projects, as soon as you say "yacht" £20 goes on the price of anything

Good quality brushes and dust free room will bring best results.

Regards Ray

[Colin BishopModerator @colinbishop34627]

As Ray says, 'yacht' anything does carry a premium on the price, as I well know, having owned one! The Toplac is around one third more than Dulux exterior brilliant white but it is very tough as it is used on yacht hulls in a marine environment which is about the harshest condition you can get. Of course new yachts are not painted as they have a GRP gel coat finish but as they get older that fades which is where Toplac and its even tougher two part epoxy paint counterparts are used to restore the hull finish. It isn't intended for below water use on full size boats as an anti fouling finish is normally used in those circumstances but for models it would be fine.

On the other hand I quite agree that Humbrol gloss enamel when applied properly should do a perfectly adequate job too. Why not just get a small tin of Humbrol gloss white and apply it to a test piece to see how it comes up before committing yourself to a more expensive solution?

Colin

[BanjomanParticipant @banjoman]

While Humbrol paints are indeed likely to be less expensive in absolute terms, given the qunatities of paint required, they are in no way intrinsically cheaper than the Toplac yacht paint linked to by Colin, but rather the opposite.

For 750 ml of said Toplac, Marine Superstore wants £22.95, or just over £30 per litre.

For a 14 ml tinlet of Humbrol #22 Gloss Enamel White paint Cornwall Model Boats are asking £1.85, i.e. £132 per litre! I dare say some searching could turn up Humbrol tinlets a couple of tens of pence less costly, but the litre price would still be around £100 …

That said, the risk, as it were, with bying such large quantities of paint as 750 ml for model work is that most of it goes unused and eventually dries in the tin to the extent of being totally hors combat.

In other words, while model paints are much more expensive, the total outlay may well be less in the end …

Mattias

[Ray Wood 3Participant @raywood3]

Hi All

Boat ownership in this country is best kept as a dream, having also been there and got the Tee Shirt ! the "tearing up Fivers in the shower" analogy is a fair one.

Having just spent £8.00 on Ronseal Hard Glaze in Homebase. I found small tins of polyurethane in Poundland for £1.00 I cant tell the difference a modellers dream.

Regards Ray

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