FOILED: Tamiya's 1/48 F-84 Thunderjet Using Microscale Foil Adhesive For a Natural Metal Finish
Finding the ultimate natural metal finish (NMF) technique has always been something of a Grail Quest for The Hobby, perhaps akin to what discovering a cure for the common cold is for medicine, developing a Grand Unified Field theory is for physics or, until 1998 at least, belting more than 60 homers in a season was for baseball. Accordingly, false hopes have been raised many more times than most modelers would like to remember. To wit, we have been teased and tempted over the years by various products claiming to simulate NMF, mostly coming in paint bottles that never quite seemed to deliver as advertised. No matter how good the results were, shiny paint is, after all, shiny paint and not aluminum, so there was always that 'close but no cigar' quality to even the best of them. Then, of course, there have always been the countless 'sure-fire' homespun techniques for NMF that have made the gossip and BBS rounds over the years ('ya gotta use organic sumac lacquer, mirror powder and yearling deerskin buffing leather, but only during a full moon', 'dust it with Crisco and graphite, then microwave the sucker' 'Electroplate', etc.). Whatever the gimmick or trick, however, a real drop-dead, knock-your-socks-off absolutely convincing NMF technique always seemed an unrealizable dream. Always, that is, until recent years, now that a small but ever burgeoning number of Fanatic Foil Freaks (FFFs) are working feverishly and diligently towards making the dream a reality.
The real kicker is that the answer to our prayers had never been farther away than the nearest kitchen cabinet all along. With a little help from a bottle of Microscale Foil Adhesive, all you need is a roll of cheap (the cheaper the better I'll get into this later) aluminum kitchen wrap, a little practice and a whole lotta patience to have show-stopping NMF aircraft models that will dazzle friends and family alike. As a fellow FFF on another website has so eloquently put it, 'looks like metal because it IS metal'. Well, that says it all. Nothing looks more like aluminum than aluminum. Accept no substitutes, folks.
OK. That's the good news. The bad news is that the technique is rather difficult, always chancy and often exasperating. But then, when did that combination of factors ever keep us from building models, right?
What you need
Cheap aluminum kitchen or cooking foil, mirror-finished on one side, dull on the other. You DO NOT want the good quality Reynolds Wrap kind of stuff Mom used on those Christmas fruit cakes. No, that stuff is practically armor plate compared with the aluminum foil I am using (Toyo Arumi - a product of resource-starved Japanese manufacture), which has a thickness of 12 microns (less than most painted surfaces). It is so flimsy it will rip if you look at it funny. Moral of the story: cheaper quality is better because it is thinner, and the thinner the foil you use, the better definition you are going to get to bring out all those good rivets, panel lines, etc.
Flat artist's brushes about 1/2 inch in width. The quality issue is paradoxical here, because while you want the brush to be supple enough not to leave trench-deep brushstrokes in the adhesive backing, you must also steel yourself to the sad fact that once you use one of these brushes in this operation, you can never quite get all of the adhesive out of it, rendering it fairly useless for other painting applications. Pliancy returns whenever the brush is soaked in alcohol and/or used for more gluing, but it will always dry to resemble something like a scale scuba flipper or rubber spatula afterwards.
Microscale Metal Foil Adhesive. Follow the instructions on the back of the bottle TO THE LETTER! That should be explanation enough. The glue seems to be acrylic-based, as its smell and color is similar to white woodworking glue. It is water-thinnable, although I have tended not to exploit this property, as I have encountered a lot of beading-up problems enough as is with the surfaces I've been working with, and I think that thinning the glue would only exacerbate this. But then again, my experience is still pretty shallow with the material, and there is a lot more experimentation that needs to be done. It seems likely that brushstrokes - which are often visible under the foil after application to the model in the technique I am using now - would be greatly reduced with thinner glue. In any case, the matter bears looking into further.
Rubbing alcohol. This is used to clean (as best as possible, that is) brushes and to clean up dried patches of glue from botched model surfaces before re-foiling.
Furniture finishers fine-grit steel wool. Use the densest, thinnest strand wool you can get. This is used not only in repair and botched surface clean up operations, but also to apply the all-important finishing touch 'patinaî of fine scratches over the foil surface to give your model a realistic NMF sheen. After all, you want your plane to look like it is made out of aviation Duralmin, not recycled funhouse mirror.
Cotton swabs and round toothpicks. These are used in applying and burnishing foil. The sharp tip of the toothpick is used to ìreviveî rivets and panel lines after the foil goes on and the wrinkles have been rubbed out (often an inexact science but you have to learn to live with that).
A plentiful supply of NEW single-edged razor blades and/or modeling/design knife blades. Working with foil requires blades as sharp as possible. Unfortunately, the foil also makes short shrift of any blade that comes into contact with it, meaning that the half-life of your blade will be measured in minutes. Literally. I went through about twenty razors and maybe half as many design knife blades building the F-84.
And last but not least, the 'Three Ps' of foiling: patience, perseverance and prayer. A little luck doesn't hurt, either.
As Shep Paine once put it, a metallic scheme is the most unforgiving surface type you can model. Every mote of dust, every finger swipe, every hesitant brushstroke - in short, every mistake you make with it will stand out as clearly and gaudily on the finished product as cheap lipstick on a filling station bathroom mirror. Although much more forgiving (if at least a bit more readily repairable) than painted metallic schemes, foiling is still no exception to this rule, so keeping the old adage about 'an ounce of prevention' in mind and taking a few prudent preparatory steps will save much heartache later on. First of all, it is crucial that your work area be as dust-free as possible. A tall order, perhaps, for a modeler, but a little preventive vacuuming or at least a peremptory sweep-up or damp cloth wiping of your table certainly can't hurt.
Addressing the foil ('Hello, foil' ! 'To the moon, Norton, to the moon!') is a matter of careful and mutual respect between man and material. Cut a workable amount of foil from the roll (i.e., just a little more than you need for the area you will cover), taking care not to foul either your piece or the remainder on the roll with small wrinkles. Big wrinkles can be rubbed out, but the small, tight ones can not. If a piece gets wrinkled like this, it is unusable.
Lay the foil dull side up (the matte finish provides 'bite' for the glue, thus minimizing beading) on a disposable, smooth, dust-free (sorry to be repetitive, but I can't emphasize this enough) surface. I've found dry cleaners' shirt-backing cardboard to work nicely. Dip your brush about a quarter-inch into the glue, then, making sure to keep your brushstrokes parallel (they'll be slightly visible after the foil goes on, so orient them to look like stress lines or 'grain' in the metal structure), start from one end of the foil piece and brush evenly and quickly over to the other side, covering everything in one pass. (PIC 1) If either puddles or dry patches appear at this stage, you can (and should) give them a quick stab or two with the glue brush, but you should do this carefully, because as a rule of thumb, it is best not to go over the same spot twice. The reason for this is that, much like uncured paint, the glue-wet brush will re-liquidize spots from the previous coating, lifting them up and off the surface as the brush passes over. These will then dry into little but very inconveniently three-dimensional rubber cement booger-like motes that are impossible to remove. If this happens, you will have to trash the piece, cut out another and start all over again.
If all has gone well, you now wait until the whitish-milky glue has dried to a dull Scotch tape-like sheen. I like to use my incandescent desk lamp as a dryer to speed this process up. If you wish to do so, make sure you've dusted the lampshade recently. If not, you'll get a nice little sprinkling on your glued foil when you adjust the light over the work area.
Once the pressure sensitive glue has dried, the foil is ready to be applied. Choose a single point near the center of the area to be foiled, and aim center-of-mass of your foil piece to touch there and ONLY there. From this single, central point, begin burnishing out towards the edges, being careful not to make any more wrinkles than you absolutely have to. After you have finished burnishing and find, to your horror, that there are nasty little air blister bubbles in the foil, just lance 'em! Make a feathery light cut along the bubble from end to end, with just enough pressure to cut the foil but NOT the plastic underneath. Burnish over this with the edge of a toothpick, pushing along the same direction as the cut, and it will all but disappear.
What order foiling?
Before beginning any foiling, you should study the layout and structural scheme of your model to determine the order in which you will foil. In general terms, when working with aircraft, I have found it best to foil fuselage, wings, stabilizers and (if present) drop tanks separately before assembly. (PICS 4 - 7) Foiling each distinct airframe component like this keeps your foil pieces small and manageable, reducing hassle in the event of 'disasters' requiring re-foiling and also helping to prevent wrinkles and spindles by avoiding abrupt angles (wing joints, etc.) in the surfaces to be foiled.
The F-84 model
The particular machine I chose to model is 1/LT Dolphin Overton's fighter-bomber stationed at Taegu, Republic of Korea in 1951. Lieutenant Overton was a 1949 graduate of West Point who was commissioned in the new Air Force and later went on to ace status in F-86 Sabres. Aeromaster produces fine quality decals (AM 48-408 and stencil set AM 148-025) for modeling this aircraft.
As goes without saying for anything recent from the House of Tamiya, the model itself went together without a hitch. Fit was flawless everywhere. In addition, the lack of irregularly curved surfaces makes this airframe a good starting project for the beginning foiler, with the only notable exception being the wingtip and fuselage drop tanks, which are shaped like something out of a calculus textbook and present a MAJOR foiling challenge. (PIC 2) The best advice I can give for working with these is to keep your foil sections small, manageable and parallel, because joints in the foil on these curved surfaces are rather conspicuous, so it's best to make them look like they are supposed to be there. Liberal uses of parallel steel wool strokes will help a lot in masking the joints. If done well, this can render them almost (emphasis on 'almost') invisible, not only in the fuel tank construction but in foiling any area on the aircraft.
Eduard etched parts were used in this model. One nice feature of this set is that it provides you with an early-type speed brake panel, which you will need if you are modeling a Korean Conflict-era aircraft. The 'swiss cheese' speed brake panel provided by Tamiya is for mid-50s, post-Korea Thunderjets (opposite chronology appears in Squadron/Signal's 'F-84 Thunderjet In Action', proving that it sometimes pays to be wary of your sources!).
OD anti-glare, yellow trim, cockpit green and yellow zinc chromate are all done in Model Master acrylics. Be sure to wash the entire model with dishwashing liquid (I know, I know - this keeps getting weirder and weirder, right?) and warm water before attempting to lay paint on the aluminum, because every microscopic nook, cranny and scratch on the surface is filled to the gills with infinitesimally fine aluminum powder which has been produced during the sanding, buffing and polishing phase, and if you don't get this stuff out, the paint will peel right off the model like a burnt omelet off a Teflon pan. I found this out, to my chagrin, when my entire OD anti-glare panel lifted off in one clean, contiguous piece along with the masking tape I peeled off after laying down the paint. Best results are to be had by using a broad, soft brush to apply the detergent straight onto the model - undiluted - and lathering it up on the surface. You'll see that it soon turns gray because of the aluminum dust. Get rid of this soapy gunk using your airbrush as a kind of sandblaster, spraying the surface with the warm water under high pressure until all the lather bubbles are gone. Finally, buff with a soft cloth, and youíre ready for painting/Future-ing/decaling/ etc.
When disaster strikes
The fundamental weakness inherent in foiling is the simple, physical fact that you are trying to cover three-dimensional, often irregularly curved surfaces with an inherently inflexible two-dimensional medium. The most obvious and commonly occurring consequence of this dynamic is, yes, you guessed it, wrinkles. I should re-emphasize this by saying that, more than just commonly occurring, wrinkles are downright unavoidable in foiling. Now, you can either let that fact break your heart and give up the whole project, or you can push on and face up to those wrinkles (ha-ha) using any or any combination of the following options: