How to achieve a Natural Metal Finish
Or
The Secret Life of Alclad 2

Text, images and models Copyright © 2004 by Matt Swan

        I’ve been modeling WW2 aircraft for a long time and while I do not consider myself to be the greatest modeler by any length of the imagination, I have acquired some small modicum of skill. Even with that I have always shied away from the dreaded NMF (Natural Metal Finish). I’ve looked with longing, yea even jealousy upon the NMF successes of other modelers but could never achieve that result for myself. Not until I started working with Alclad 2 a few years ago. Alclad 2 is a wonderful lacquer based metallic finish paint but it must be handled with the proper care and methodology.
        Typical problems with other NMF finishes include but are not limited to; lifting when masking like enamel based silvers or messy applications associated with rubbing compounds, and there’s another thing – rubbing. I don’t know about you but I am in no hurry to expend any more elbow grease than absolutely necessary. Even if you are so lucky as to finally achieve a good looking finish with these other products wait until you try to seal it up with a clear coat – suddenly the effect has been lost!
        Alclad doesn’t do it all by itself though, a proper base (primer) is absolutely necessary. Many modelers try to use an acrylic primer for Alclad and Alclad even offers their own acrylic based primer. What kind of insanity is this, I ask myself. This kind of primer only works some of the time and after putting many hours of detail work into a model combined with aftermarket resin packages and custom decals a “some of the time” primer is not something I want to deal with. I cannot count the number of times I have heard from modelers that their primer lifted, wrinkled or cracked after the Alclad was applied or the dreaded orange peel has appeared. There are only two true options for an effective primer for Alclad 2, Krylon Gloss Black #1601 (a lacquer based paint) or a good lacquer based automotive primer. Use one of these two products and it will work every time! You just can't beat the solvent action of the Alclad welding itself to the lacquer primer, which in turn, has welded itself to the bare plastic.
        I prefer to use the Krylon product, as it will leave a smooth, glossy finish that needs no additional work before applying Alclad. If you do find a defect you can sand this product and recoat. The automotive primers will give you a rougher finish that requires sanding with very fine paper, somewhere around 400 to 800 grit and you should be wet sanding to prevent your paper from blinding up. Let me refer you back to the “elbow grease” comment, this is more work than I care for. Regardless of which product you choose to work with there is an immediate problem that has to be dealt with; that rattle can gives you virtually zero control over paint flow. It’s an all or nothing proposition and that is not acceptable. First we must decant the paint. There are a couple of approaches to this, one involves tipping the can upside down, venting the propellant, waiting for the remaining paint to degas and re-venting before running a nail into the can and draining the paint. Not only is this dangerous but it consumes a lot of that precious elbow grease and requires a container with a good seal for storage – bad idea.
        Let’s try another avenue that has much less danger involved. Just to be sure that we don’t make a mess it would be a good idea to do this overtop yesterday’s newspaper. I take a good sized drinking straw – not some little swizzle stick but something you could suck a milk shake through, cut off about four inches off the straight section of the straw. Now make sure that your can of paint has been properly shaken and hold one end of the straw to the business end of the spray head. Hold the other end into a collection cup – I use old 35mm film canisters for this but anything of that general size should do. Be sure that the end on the rattle can is held tight to the nozzle and spray. You’ll get a nice little stream of paint into your collection cup. Generally speaking you will need no more than half a film canister of paint to complete even the largest projects and you don’t want to have more than needed. If you need more you can always come back and repeat this step. One major advantage to this method is that the balance of your paint is still in that huge rattle can and can sit on the shelf for months if need be and not go bad. Consider that an 11-ounce can of Krylon paint sells for about $1.25 at Wal Mart and will prime many models while those specialty primers that only work sometimes cost several dollars for just a few ounces.
        Now that we have collected our paint it can be transferred to our favorite airbrush where we have very good control of paint flow and quantity. It is not necessary to thin these primers as they are already of the proper consistency. It is necessary that you have completed all filling and sanding on your model prior to priming. You want the model to be as free of dust and debris as possible. I wipe the model down with a Micro Sheen cloth first. This cloth has an interesting ability to reach into fine lines and rivet detail to remove dust particles from sanding as well as removing any residual fingerprints. Just before heading to the paint room I will dust the model off with pressurized air to remove any last particles. I do this away from the area that I will be painting in so that there is not a lot of dust floating in the air looking to attach itself to my freshly painted model. I generally set my air pressure to around 15psi and shoot from a range of four to six inches. This stuff is very thin and should be applied over several light coats. As a rule of thumb I will put down at least four coats of primer waiting five to ten minutes between coats. Once your model has been completely primed you must let it cure for a day – minimum. I usually wait two days before proceeding.

        Now is the time to check for errors in your finish. Any rough spots should be sanded out, seams need to be double-checked and any masking should be inspected for spots that may have lifted from the model. Any surface touch-ups can be repainted but don’t forget to let this cure for a day or two again.
        Now we are ready to add some final color to the model. Just like when the primer is applied, this does not need to be thinned and goes on with several light coats. Be sure to allow fifteen to thirty minutes of dry time between coats. Once this has had a day to dry you can safely mask over top the finish to paint contrasting panels. I have never had Alclad lift with masking tape when the proper primer is used. If you use an acrylic primer this can be a problem. As far as the contrasting panels go, for most of my standard NMF schemes I use Alclad Aluminum #103 and lay some Dark Aluminum or Magnesium overtop. If you are doing something like a B-36 you would of course be using Magnesium as your primary color but the standard Aluminum, White Aluminum or Dark Aluminum are good for contrast. There are plenty of other metallic colors available like Gold, Titanium and burnt exhaust. You can also use virtually any other paint like acrylic or enamel overtop this surface for additional markings, like invasion strips, without fear of adverse reactions.
        All the paints we have been using are lacquers so it just makes sense that we use lacquer thinner to clean up. I use a plastic pipette to add a few drops of thinner to the airbrush and blow it through – a couple of treatments like this cleans up the airbrush pretty good from both the Alclad and the primer. Having some lacquer thinner around is good for many things, you can thin your enamel paints with it and extend their shelf lives and you can use it as a needle lubricant for your airbrush. Not only is it good for that quick clean between colors or from today to tomorrow usage of your airbrush but you can also soak your brush pieces in it for a thorough cleaning. Let me add a cautionary note here, some cheaper quality airbrushes may not react well to lacquer thinner. I am using Badger airbrushes and know that Thayer & Chandler, Iwata and Paasche airbrushes are fine with it. Read you airbrush manual before using lacquer paints in the equipment. The fumes from these paints and thinners are dangerous so please paint in a well-ventilated area and use proper respirators to protect your health.
        Alclad leaves such a nice, smooth finish that you do not need to apply any clear coat prior to applying decals. I have never had an issue with cured Alclad reacting with setting solutions like Micro-Set or Micro-Sol. Once your decals have set and dried completely (24 to 48 hours) you can coat the model with Future floor polish to seal the decals. This will also make it a little easier to apply any weathering like a sludge wash or ground pastel chalks. Some modelers have expressed concerns with the clear coat changing the tone of the Alclad. I use Future floor polish over any other gloss clear coat and have never experienced a color shift with it. Sometimes it does look a little weird going on but just let it dry down (overnight) and it will look just fine. If you are not planning on using Future to seal the decals you may want to trim the clear carrier film as close to the artwork as possible before wetting the decal.
        That’s it! Not very hard at all. The most important item through all of this is patience. You must let the paint cure completely between priming and top coating. Let’s do a quick review …..
1.         Complete all surface preparation on the model, i.e. seams.
2.         Make sure to shake the can of paint well then decant into a collection cup.
3.         Transfer primer into airbrush and apply four or more coats for good coverage. Remember to give each coat ten or fifteen minutes to dry.
4.         Let primer coat cure for one to two days before continuing.
5.         Apply Alclad 2 with your airbrush – four or more coats with dry time between them.
6.         Apply decals and seal with Future floor finish.
7.         Add any additional weathering effects and reseal with Future if needed.

Here are some final results of this process