Saturday, December 5, 2009

Acrylics or Enamels?

 



 It has to be the biggest question in model painting today, beyond choice of brushes or airbrushes, beyond colour selection: which type of paint is best for your project? There are modellers who have switched entirely to water-based acrylics for all spray work, for the health benefits: nontoxic paints are a major factor and not to be taken lightly. When you’re used to the light, sweet smell of acrylics and their water cleanup, to start spraying solvent-based paints and their spirit cleanup is a rude reminder of just how frequently and casually we poison ourselves with the things we invite into our environment. Got a spray booth with a ducted exhaust fan? Good for you, but most of us make do with an open window and sometimes it’s just not enough.

Like many modellers, I have both types of paint in stock. I first bought acrylics when tackling vinyl subjects in the early 90s, and I must say the Tamiya paints I bought have been extraordinarily long-lived. They’re still good over 15 years later, all they need is a stir. They haven’t made the old, large bottles in many years, possibly because people discovered the paint lasted remarkably well, and for the rate of usage a smaller quantity was just fine. I have scores of Tamiya shades, plenty of useful colours, and my collection grows gradually. But I also have hundreds of enamels, the ubiquitous Humbrol range and Testor Model Master (which despite being superb quality, with an easy-stir jar and an enormous selection of specialty-matched shades, is getting hard to find in Australia, as Humbrol and Tamiya have grabbed the popularity).

I have not brush painted a model in 30 years, but today when I spray enamels I do so outside, which is a nuisance. Acrylics I can use indoors with simple ventilation, which makes them easy and convenient. But what about detail painting by brush? This is where the real applicability of the paints comes to the fore. Acrylics spray superbly but they don’t brush worth a damn--at least the Taniya variety. You can thin them a little and that helps, but the drying rate is like lightning and in one minute a brush is unusable -- clean it and start over. This seems a characteristic of the Tamiya range in particular, they are by far the most available here and I have sampled no others at this time (but I’ve heard others dry even faster…)

By comparison, dipping a fine brush in enamel paint provides familiar flow and control, and one can concentrate on the finesse of the task rather than fighting the characteristics of the medium. The same thing applies when airbrushing, though on a longer timescale. When used to the tip-drying characteristics of enamel, acrylics can bite you: you must keep the job moving when you’re working with the nontoxic paints, and when it’s done be sure you’re finished and clean the AB at once. This tends to lead to wasted paint, as when forgotten bits are noticed you need to mix more, and if using a syphon-bottle AB there is a minimum amount the airbrush will actually pick up from the jar. If working in enamels you have the extra working time to consider the job from all angles, turn the thing around again, look at it in different light, go 30 seconds or more and be sure the paint will still flow normally when you press the trigger.

My impression is that enamels and acrylics will continue to share the marketplace. Enamels flow on so smoothly they are a joy to use, they are a ‘friendlier’ medium than acrylics, you can polish their finish just like automotive paints (which ironically have all been acrylics for the last 25 years at least), and the range of precision-matched shades is enormous. The major manufacturers must have churned out over a billion bottles and tinlets in the last 40 years, in fact probably far more, Humbrol alone used to produce 25 million tinlets a year in the 1980s, if I remember correctly, and that’s an awful lot of paint in collections out there. I personally have tins that date from that era and the contents still slosh. But if acrylics were friendlier, dried slower, brushed better, and were available in hundreds more shades, precision-matched to historic sources, I would be using them more often. I have no wish to poison myself, and while the chemistry involved with acrylics is almost certainly not 100% harmless, it’s a significant improvement.

2 comments:

Peter Lynch said...

Few modellers seem to try mixing retarders in with their acrylic paints. Manufacturers claim retarders have some effect on drying times. Does anyone out there use them and could they confirm if drying is slower?

Mike Adamson said...

Hi Peter,

Interesting question, I've heard of them but not seen them here in Australia -- there again, I've not looked. I checked the FineScale Modeller forums for anything on this topic and found a couple of threads with user's comments.

It seems retarders can take the form of either unpigmented carrier (the transparent fraction of the paint) or a detergent-like cleaning fluid which acts to slow drying. One user claimed acrylics remained wet for five minutes -- which may or may not be a good thing.

I have encountered problems with tip-drying only under warm weather conditions, or when I'm spraying a large amount of a colour, so that a gradual buildup of fine particles can occur. Otherwise, I've found a minute or more will elapse before Tamiya acrylics will not readily resume spraying.

Hope this helps,

Cheers, Mike