Need help with metallic paint pealing.

Peeling is probably due to poor adhesion by the paint to the bare plastic beneath. Your best bet is to strip off all of the metallic paint, use a good primer or base coat, and then apply your metallic top coat. On my last NMF build I used a Humbrol gloss enamel under the metallic coat, and it came out sweet. 

primed with gloss enamels

finished

Best to start over with bare plastic when you are doing nmf.  I often just spray over bare plastic depending on the color and quality of the plastic, but if I want high shine I use a dark blue with a gloss finish under the nmf.  I don't like to wait for gloss enamel to dry so I either polish a flat blue, or put a gloss coat over it, once again Alclad Gloss.  I use Alclad paints, it may be that other paints have different adhesion qualities.

I am very lazy about cleaning plastic parts, just Windex usually unless I forget entirely but it is also possible that there was still mold release on your model where you had adhesion issues.

My thought also is to strip it. If you're using Mr Color paints they are lacquer, so I personally would prime with their lacquer based Mr Primer Surfacer which I stock for my lacquer paint jobs only ( otherwise I use Stynylrez). Then base coat in something dark gloss or semigloss over that, others mention blue which may be ideal. Then your metallic coat. You have two choices: go this soup to nuts route or go to bare plastic, I've seen the Lacquers done either way, though while some folks feel lacquer bonds fine to plastic, to me it's always iffy to shoot color coats to bare plastic be they lacquer or not. As sometime the adhesion can be lost in spots a decade down the road.. But your plastic needs to be clean in any case anyway..

Windex may be fine as long as you use a scrubby or tooth brush then rinse real well. I've never tried it but it makes sense to me. The standard is a dish soap bath, usually a drop or two of Dawn in water. I also use mineral spirits. Your surfaces need to be free of stuff, even skin oils.

Promise not to laugh or Get mad?

     When using Metalizer or Metallic paints, besides a high Quality Primer I wash the Model BEFORE, I put the Metallic coating on it or Just use different types of Foil chrome. I got tired of redoing Aircraft becuse of this Interminabley present problem.

I know people do it but for me, I would have 0 interest in foiling an entire aircraft. Or much of anything else for that matter.

There is no way to seal down a coat of paint that isn't adhering well. Best to start over. I prime with my supply of Testors square bottle gloss black. It takes about two weeks to harden.

Bill

I'm with everybody else on this.  Strip it to bare plastic and start over.  When I have to strip paint, I like to use 99% isopropyl alcohol and a cheap electric toothbrush.  The vibration of the electric toothbrush eliminates the need for you to do all of the scrubbing and also eliminates the large movements with a manual brush that can end up breaking things off of your model.  I wash all of my parts before priming with a soak in undilluted Simple Green (don't do this as an intermediate step if you have a painted/primed surface that you want to keep...Simple Green tends to start removing paint).  I then rinse the parts under hot water in a fine kitchen strainer (keeps even the smallest of parts from going down the drain) and give them a quick dunk in the 99% isopropyl alcohol before letting them air dry on a paper towel.  The dunk in the alcohol at the end just helps them dry faster.

I prime everything...even the smallest of parts...with decanted Tamiya Surface Primer, followed by a base coat of gloss black.  I have found Tamiya's LP-1 gloss black to be great for this.  It cures quickly, but not so quickly that you can't get an even gloss with it.  Then the different panels of Alclad go on.  I use Tamiya Masking Sticker Sheets to mask with.  Its adhesive qualities are difficult to explain.  It is infinitely "re-stickable" and grips the surface securely, while at the same time not being so aggressive that it damages things.

I used all of the above to paint the different panels on this F-4B stabilator, with no issues of metallic paint peeling off.  After everything was painted and discolored to my liking, I sealed everything with the AK Gauzy Shine Enhancer stuff.