finishing a bare metal aircraft

well yes using more colors is best the trick is to know where to use which color... i tend to use one color on most of the model say a mustang then for access doors and panels like gun access doors would be a faded color like if you use alluminum to coat the wings then use something that looks worn like a mix of alluminum and silver or any mix of colors...i perfer to keep the amount of colors to minimum on warbirds like mustangs and thunderbolts but on bare jets say F-100 the color range is pretty big and theres pretty cool things to do with the foil.. say you want the engine to have that heat distortion tint well its easy if you take a cup and mix enamel paint thinner with a number of different options then drop the foil in there it will take on that distortion look but you have to be wary of time as in if you wait too long the enamel will eat through the foil which can still be used as a way to paint on paint chips on the cowling or where ever you like just ask around theres too many tips with foil to name!! hope this helps and good luck

Altering the grain doesn't produce the best results in my opinion. I can get a variety of shades by using the shiny side of the foil, or the dull side of the foil. buffing the shiny/dull side with steel wool also gives additional shades. If you submerge a piece of foil in a bleach/water solution with a fishing weight or pennies you can get even more shades.

this is a P-51 Mustang I used this technique on:

Even though I am somewhat of a novice in planes this worked for me and helped me "get the gold". I used five different brands of aluminum foil dull side out  ,as well as shiny side out .There are ways to change the texture on aluminum foil . Such as if you want a panel duller , but , somewhat shiny ,  use childrens toothpaste and gently polish the surface BEFORE you put it on the aircraft .Another thing I found out is this . If a shiny panel isn,t shiny enough , then take a new (No scratches or flaws in the surface) X-acto no. 1 knife handle and gently rub , in one direction , the foil , AFTER you,ve installed it .  This will bring up an incredible shine . I discovered it by accident smoothing out bumpers on model cars . After you,ve done all this and installed the foil and are satisfied with the look of the panels ,  overlap them slightly over the seam or panel line then using a NEW X-ACTO blade cut through both layers. This will insure no unsightly gaps between panels . Polish it with a clean soft cotten rag (old T-shirt) then put on all the decals . Wipe gently and then clearcoat with future or clear enamel and VIOLA a beautiful bird . There is one more part to this tip though , DO NOT use the high priced brands of foil . I make my own and I use the house brands from the local market , WAL-MART , DOLLAR GENERAL , etc.( you get the picture ) They are generally shinier and thinner which makes them snuggle down better in the lines and curves .          tankerbuilder 

Ditto. I drove my wife bonkers when I assembled my stash of foils. I’d spot a seedy dollar store in a run-down strip mall and buy one roll of every type (I kept records of the brands). The ‘secret’ most people don’t know is that the shiny side / dull side is an artifact of the processing. It is done with TWO layers (matte side in the middle) because it is easier to roll it that way.