There's pain in painting ... but pride in the result

by Mark Rothfield on 24 Oct 2011 Her name was Shad and she was red, white and green like the Italian flag, neither of which I could stand (with no disrespect to Italians).

I found her in the corner of a hobby farm on Sydney's outskirts, suspended on a makeshift slipway. Her tandem-axle trailer sulked among dandelions. Leaves and berries littered the cockpit while inside she was dank and unkempt.

Not a great first impression, but I wasn't to be dissuaded for I'd driven through peak hour and pouring rain to find the property.

I haggled for a while with the owner before he named his rock-bottom price. I scratched my chin. It was the right boat at the right price … in the wrong colour.

That could be fixed, I decided, before shaking hands.

Upon getting the boat home the clean-out and clean-up began. Out came the cushions, carpet and accessories, then I went to work with various cleaning products. It's amazing what a difference cosmetic detailing can make. But there was no disguising the hideous topsides. Painting was called for …

Brush, Roll or Spray?
The easiest way to paint, no question, is with a brush, and it's certainly fine for timber craft. But it is almost criminal to leave brush marks on a smooth gel coat surface; you'd be better off polishing.

Spray painting was the next option but in my situation this was relatively expensive. Much of the cost vanishes in thin air, in the form of overspray, and I didn't want to overcapitalise. Also, spraying has to be done professionally in a sealed environment such as a spray booth, whereas I was hoping to do much of the work at home.

I'd previously read about a roller/brush technique that was said to yield a finish almost as good as spraying. You roll on, and then tip off with a brush, so it's reasonably fast. And it's more efficient than spraying, with a fraction of the paint usage. It was the path that I decided to follow.

Paint Brands
The choice of paint was the next decision and from a scientific viewpoint I must profess total ignorance. I don't have a clue what goes into marine coatings, so I couldn't recommend one over another. They're 'polyurethane', that's all I know.

But amateurs should not need a science degree. It's user-friendliness – ease of mixing, pot life, paint flow etc – that really counts, along with price.

Some paints are formulated for spraying and advise against rolling or brushing. The other consideration is whether to use one-pack or two-pack, the latter having a converter - two-pack is worth the extra money to achieve a more durable finish, at least for topsides that cop a beating.

Preparation
As anyone who has painted a house knows, preparation is everything. What is pain-ting without a little pain?

As the old adage goes, you use as much paint to achieve a bad finish as a good, long-lasting finish.

Given the premium price of marine paint, and the nature of the environment, it is even more critical you get the prep work right on your boat.

A good bonding between the old gel coat and the new paint is essential. Second, the surface must be as fair as possible to obtain maximum lustre and remove any blemishes that would otherwise be highlighted by the gloss.

Trailerboats have an advantage in that you can do the prep work at home. Also, the height is such that you don't have to erect scaffolding. That said, moored craft can be done on a hard stand area at the same time as antifouling.

The whole process takes about five days, using my boat as a guide.

There is no rushing the first part of the job, sanding. Shad had a number of gouges that I patched with epoxy filler. I then attacked the hull with an orbital sander, using 120-grit paper. It took about eight dusty, back-breaking, arm-tiring and hand-numbing hours to complete.

Don't go too far with the sanding because a slight grittiness is needed for the primer to grip. Also, pinholes tend to appear in the gel coat because it's a very porous coating. You have to look hard for them because they show clearly when the final coats are applied, at which time it is expensive to fix.

Next was taping the waterline, toerail and fittings, and finally the time had come to rid Shad of her stripes.

The primer was a high-build epoxy that helps to fair the surface when you sand it. Spraying the primer would save sanding time but again it's wasteful and specialised.

As it happens, there are a few tricks with rolling primer. One is to do the job early in the cool and calm of the morning (to extend working time), the other is to thin it down to get a nice flow.

It's important to use a good quality roller, suitable for two-pack paints, with a nap of no more than 5mm. This stops the crocodile-skin ridge effect left by some rollers, which can be a nightmare to sand.

You have to work quickly because the primer dries quickly and the last thing you want is an uneven build-up. The natural tendency is to work from the bow backwards and the gunwale downwards because it gives a known starting point.

The advantage of fast-drying paint is that the second coat can be applied soon after the first then, because you're trying to achieve a high-build, you can apply the third.

It's best to sand the primer within four days, after which time it achieves maximum hardness. A trick of the trade is to spray on a black guide coat using 3M powder shadow coat (aerosol paint clogs the sandpaper), which indicates how much sanding needs to be done and where you're up to. The guide coat fills the crevices and once it disappears you've sanded enough.

The orbital gets another thorough workout with 220 grit paper; suffice to say it takes even longer than the original sanding session.

The Final Coat
So far all the work had been done with Shad parked on the street outside my home. This was fine except that the weather was wavering between strong westerly and wet southerly, neither of which was conducive to painting.

It was at this point that I decided to call in a mate who has a large shed and also vast experience with applying marine paint … experience that has taught him to use the finest foam rollers and paint brush you can buy.

He filled the last pinholes that the primer had highlighted, then gave it a final sanding to his satisfaction. All the dust was removed from the hull and surrounding floor and a wax and grease remover was applied before a wipe-down.

I produced my tin of paint, all one US quart of it – less than a litre – which I assumed would only run to one coat. This concerned me because the stuff, frankly, was as dear as poison.

Ever wondered how to get the ratios right in an unmarked container? The trick is to put a metal ruler in the tin and pour up to appropriate level. Simple.

After stirring the pot he allowed 20 minutes for the chemicals to combine. While that was happening my mate moistened his $80 brush in solvent.

Then the magic began, as he rolled a section about a metre square. Air bubbles were prominent but the master painter quickly followed up with his brush, tipping off vertically to help prevent the dreaded drips known as ‘curtains’.

The paint immediately shone like a mirror. The coverage and depth was amazing. Indeed, anyone who reckons that watching paint dry is boring should see this stuff in action.

We worked along the hull, doing manageable areas with the roller then consolidating with the brush. At one stage the brush began pulling so more reducer was added to the mix. Twenty minutes later the topsides were glistening, and a mere 300mls of paint had been expended.

The coat was allowed to dry and the following morning was given a rub down with 320g paper to remove any imperfections. It got dusted off again, hosed and dried before the second coat went on. It added further lustre and, as there was still paint left, a third coat went on the following day. It was the money coat.

Three coats on and we'd used less than 900ml of base paint. Spraying may have used up to three times more paint, in which case you'd use a cheaper product.

You have to develop a feel for the flow … get it wrong and it's curtains (drips). I'm not sure an amateur would get such an exceptional result but certainly the prep work is a no-brainer.