Page 12. Autumn 2018. Paint at last - primer & undercoat.

At last, we could paint. Much research was done on the subject of paint. Many people have asked why we did not spray the caravan. The simple reason is because we do not have a heated spray booth, compressor, spray gun and breathing apparatus to protect us from poisonous isocyanates in 2 pack paint. In addition, I had an accident with a low pressure spray gun years ago, and want to avoid them. This left us with brushing or rolling, and my research lead me to enamel coach paint, as it flows out whilst drying slowly, leaving few if any marks. There are several manufacturers of enamel coach paint, and plenty of advice on the internet. One thing I discovered was that everyone on discussion forums is an expert, but they all have different opinions, making it difficult to know what is right. The only information that was consistently agreed upon was to use the same manufacturer for all your paint products, to ensure compatibility and avoid possible adverse reactions.

Our caravan has both aluminium and fibreglass body panels, and these require different primers. Aluminium needs an etch primer, whilst fibreglass can have normal primer. I ruled out a few of the makers as I could not find etch primers in their range, and eventually whittled the choice down to Tractol/Tekaloid products. Even then, we had to source them from two different suppliers. Lou phoned tools-paint.com who were very helpful and we bought most of our stuff from them, including some absolutely brilliant 3M disposable respirators. The paint really stinks but you cannot smell it at all though these masks. Smith & Allen ignored all my e-mails requesting advice, but their website (www.smithandallan.com) includes some very useful downloads with technical data and painting tips. We bought a few bits from them. Tractol primers and Tekaloid coach paint are compatible and their technical data sheets recommend the number of coats of each.
Fibreglass practice piece.
I have to point out that, other than me painting a couple of cars (not very well) as a teenager, neither of us have any experience in this field. Other peoples’ opinions can’t always be trusted, and restorers we spoke to had used different makes of paint, so it would not necessarily behave the same way as our chosen brand. We decided that having some test pieces would be useful, and it turned out to be an invaluable idea. We used an offcut of fibreglass and some spare aluminium, and painted them just like we would paint the caravan. It allowed us to see how quickly it dried, what the finish would look like, how the paint would stand up to stone chips (I hit it with a hammer), whether we could rectify runs and sags, all without touching the actual caravan. Each coat of paint on the Viking also included some on the test pieces. We could touch that to see if it had dried without leaving fingerprints or grease on the ‘van.

I will mention masking briefly. Newspaper is not waterproof and needs miles of tape to stick it together, so is not the best thing for masking. We used rolls of brown paper; if it's good enough for spray shops, it's good enough for us. I asked several professional decorators to recommend a masking tape and they all said Frog Tape. It's quite pricey but it seals well and peels off leaving hardly any residue. It must be borne in mind that paint might be touch dry in 24 hours, but it takes a week or more to fully cure. Do not stick tape on paint less than a week old or you will peel the new paint off with the tape.

Primers and paint were applied with a 4" foam roller. The chemicals in the paints cause the rollers to disintegrate after a while, so we needed a plentiful supply, and we soon learned when to go to a new roller before bits of foam came off and stuck in the wet paint. We used Purdy and Hamilton brushes to obtain the best finish possible; 99p brushes from B&Q will leave lines and bristles in the paint. Lou thoroughly cleaned the brushes after each use as they were very expensive. Screwfix sell disposable paint tray liners and they saved a lot of cleaning, plus prevented cross contamination between products. Whilst on the subject of contamination, we wore disposable paper suits and nitrile gloves to protect the paint job from us.

We started with etch primer. There are aluminium vents attached to fibreglass panels so these were brush painted first, along with the awning rail on the nearside and gutter on the offside that we had not removed. On the body, the Tractol 729 single pack etch primer rolled on well. It flowed out into a smooth coat and did not require laying off. It dried incredibly quickly. It was harder to apply neatly by brush. The first coat was quite thin so we opted to apply a second coat to ensure thorough coverage.


Awning rail primed


The fibreglass, and the etch primed aluminium, were covered with two coats of Tractol 816 single pack primer undercoat. I cannot find anything good to say about this product. It does not brush on; more like a smear. It does not flow out, and cannot be laid off. It dries quickly, resulting in a ridge on the roof where we could not work fast enough to keep a wet edge. The worst part however, was the stippled texture left by the roller. Over a year’s worth of work creating a smooth and blemish free body was ruined. By this point in the project, we wanted to complete the paint before winter 2018, but the only way we could get our perfect bodywork back would be to spend weeks building up layers of undercoat and then even more time sanding it back to a smooth finish. The Viking had already taken far too much of our lives over the last two years and we were determined it would be finished in Spring 2019 (ha ha! Wrong again).
We both took a week off work and each worked seven hours a day for six days. By the end, we had sanded off the high points of the stippled surface, but the dimples remained. Our test pieces had shown that two coats of gloss paint would partially obscure the dimples and we would just have to accept our paint job was not going to be as good as we planned. We then had to clean inside the shelter and wash the caravan again (several times) because of the thick layer of white dust that had settled on everything.