Preparing for a Natural Metal Finish (NMF)
By Brent Theobald
One factor to consider when building a kit that is going to be polished is the kit will need to be able to withstand the rigors of polishing. Wing roots and trailing edges are particularly vulnerable. Wings want to flex, cracking the wing root joint. Wing chords want to flatten breaking the plastic at the trailing edge of the wing. It is advisable to beef up the structure of the model during construction with sprue. Do not pack the When filling gaps on the NMF model use gap filling super glue. If you do use putty, seal it with super glue. No matter how much the putty is polished it will never look the same as the surrounding plastic. The putty will appear rough once the paint is applied if it is not coated with super glue. Super glue can be polished once it is dry. Putty also seems to shrink too much. Super glue does not do this either While super glue can be polished. It can be difficult. Super glue is easier to file, sand and polish within an hour after is has been applied. When filing and sanding it is a good idea to use electrical tape to protect the model from accidental or "extra" filing. The electrical tape conforms to the shape of the model and doesn’t get soft when wet sanding. Masking tape just comes apart when it becomes wet. The use of tape can save time removing inadvertent scratches later. Use a commercially available plastic polish. Good results can be had with Novus plastic polish. Use grades three and two. Grade one is a protectant of some kind and should not be used. It may be a wax. Do not attempt to use Novus as a paint polish. Polish the entire model. If scratches appear, go back and sand it or steel wool it until it clears up. Then polish some more. When the polishing is done the entire model should have a mirror like finish.
Many modelers agonize over which metalizer product will work the best for them. Some modelers destroy their chances for a good NMF before they ever open the jar of paint. If the plastic is not prepared properly before the metalizer is applied, it won’t matter which brand of paint was chosen.
wings with modeling putty! The putty will soften the plastic then shrink, deforming your wing. However, epoxy putty, such as Milliput, does work nicely for this.
After the gap filling super glue is rough filed and sanded the model should be finish sanded with fine sandpaper (600 grit to 1200 grit). Then fine grades of steel wool (000 to 0000). Do not work on areas of the model that have not been filled, filed or sanded on before. Finish the entire model at this point will only add work. The model should have a dull uniform appearance where it has been sanded on. If there are any visible scratches go back and sand some more. Metalizer has been called a "scratch amplifier" before with good reason.
Novus will remove paint. Toothpaste (not gel) works as a plastic polish too. The toothpaste does not work as well as the Novus, but it does leave the model with a nice minty smell. Resist the temptation to use a Dremel Tool to buff the plastic. This will melt it.
All this does sound like a lot of work. All paint jobs rely on good preparation in order to achieve a good finish. Metalizer paints more so than others. Natural metal finishes are among the hardest to achieve because they show every flaw in the surface of the model. These first few steps all lead to a beautiful natural metal finish by removing those flaws.