Un'altra domanda banale...

[Q] Come posso avere una finitura metallica ad alta lucentezza sui miei modelli di caccia o di auto sportive?
[A] martin@aio.jsc.nasa.gov (Toby B. Martin 7/94)
Salve gente! Ho finalmente completato la prima fase delle mie prove di finiture 'Natural Metal'. Queste sono le mie osservazioni raccolte usando varie vernici metallizzate. Non essendo un esperto, è probabile che i miei risultati siano simili ai vostri, a meno che voi siate degli esperti, naturalmente.
Per iniziare, con le vernici metallizzate la superficie del modello dovra' essere il piu' possibile liscia e priva di graffi. NON usate i soliti stucchi per modellismo, dato che sono troppo porosi per queste colorazioni. Alcuni stucchi epossidici possono andare bene, ma mi sono trovato male ad usarli perche' sono molto duri. Qualcuno propone di riempire le giunture con plastica liquida (ritagli di sprue sciolti nel metil-etil-chetone o nella colla liquida), ma mi sono trovato molto bene usando colla cianoacrilica, del tipo normale o denso. che si puo' carteggiare e lucidare fino ad ottenere una superficie levigatissima. La preparazione della superficie inizia con carta abrasiva n.400 o 600 bagnata, progredendo fino alla n.1000 o piu', se ne avete, quindi si passa al Bare Metal Foil's Plastic Polish, un prodotto capace di ottenere una superficie che sembra vetro. In questa fase siate scrupolosi poiche' le vernici metallizzate mettono in evidenza ogni piu' piccolo graffio. Non usate primer, che sono troppo granulosi per queste vernici, o vi tirerete la zappa sui piedi.
A questo punto avrete capito che e' tutta questione di lucidare, lucidare e lucidare.

Testor's Model Master Buffable Metallics. I read through the pamphlet that comes with these paints and followed them as closely as possible. I used 20 psi in the air brush (a Badger 150) and a color cup. The paint is very thin and goes on very smoothly, I didn't get any thick spray or graininess...to steal an advertisement, no runs, drips or errors. The finish is very impressive, bright and very metallic.
BUT when I attempted to polish some of the panels, I ran into several things that need to be kept in mind.
First, don't touch the model without a soft cloth towel/rag or cotton gloves...it is very easy to smudge the finish.
These smudges can be polished out, but this may ruin your plans for shiny/dull panel layout.
Second, I used post-it notes (I also used the low tack Scotch tape-in the blue plain box, with similar results) to mask the panels I wanted left unpolished, be careful here even the low tackiness of the post-it pulled some paint up and left the surface with a different texture.
This new texture can be used in your panel layout if planned for (I didn't).
The wet newspaper trick as spelled out in the pamphlet works very well for masking for other colors, but poses some problems when masking for buffing. It is easy to tear the wet newspaper or move it from the desired demarcation line.
Using a cotton swab (better known in the U.S. as a Q-tip) or the little eye makeup cottony/felt swabs found in your wife's (or girlfriend's) makeup case can help you polish one panel at a time.
Another thing I tried was to just lay down a piece of paper (no sticky stuff) along the line I wanted to polish and polished around the panel then did the interior...kinda like coloring when you were a kid, outline the panel then fill it in.
As I glance at the pamphlet again, non-buffing metalizer can be masked with the low tack tape (not the buffing kind...guess I should have read that twice).
The best results were when I painted a base coat of NON-buffing Metalizer then masked with news paper...then sprayed buffing Metalizer where I wanted shiny panels.
Be sure to mask around the panels with post-its, the buffing Metalizer will bleed over onto the non-buffing areas. (Hey I just thought of this, how about buff everything up to a nice shiny finish, then mask with newspaper those panels you want left shiny, then spray another coat of paint for the dull panels...hmmm, gotta try that.)
Third, I had trouble when I attempted to polish the panels that were filled with super glue...the paint came right up.
I haven't found a trick to solve this one, except go easy on the filling and plan a panel layout that won't have you polishing the filled areas.
Perhaps a different superglue may not cause this problem, I used Bob Smith's (often relabeled as your hobby shop's brand). But don't despair, all of the problems above can be easily corrected.
If you rub all the paint off in an area or don't like the texture of a panel or 'go outside the lines' while polishing, another quick light coat of paint will cure it.
The paint is so thin that you won't be able to see where the underlying paint was.
So it just takes some time and patients to get a good finish with the Testor's.
Finally Testor's suggests to seal the metalizer with Metalizer sealer, I tried this (on a scrap)...don't do it, it makes the finish hard and easy to handle, but the finish doesn't look quite as realistic.
One last thing, MM metallics are lacquers, not enamels so you will need to get some lacquer thinner to clean up with.
I had equally good luck thinning with the Metalizer Thinner as with regular 'hobby grade' lacquer thinner (i.e. it is clear...my bulk lacquer thinner is a little yellowish, maybe that is why it is super cheap).
I had no ill effects applying decals with no additional gloss coat, the metalizer finish is very smooth.
There were no bad reactions to Microscale Micro Set, Sol or to Solvaset (my first decaling solvent, it was given to me by a Model Railroading Uncle back in the mid-seventies...still using the same bottle!)

SnJ Spray Metal I read and re-read the tips on using SnJ in the March '94 issue of FSM and tried to follow them as much as possible (I didn't sand with 600, 800, 1000, ..., 2000 grit sandpaper. I did the same as above, upto 1000 then straight to BMF plastic polish).
I set the air pressure to 20 psi again with the Badger 150 but this time with the paint jar...the color cup is not recommended. I think this is because the metal particle seem to settle out of the medium and get sucked into the airbrush clogging the tip and giving a grainy spray.
I know this 'cuz I tried it. Also the author of the FSM article suggests using a siphon tube that doesn't reach the bottom of the paint jar, to avoid the same consequences with the color cup (this is a good idea...I messed it up too).
I sprayed several light coats, several minutes apart and got good results. As long as I remembered to stir or swirl the color in the paint jar around before resuming spraying...otherwise the same old clogged tip and grainy spray. After learning these lessons (the hard way) I got a nice solid overall finish on the model.
This stuff you can handle an hour after you're done spraying (actually I stuck my finger in it after about 2 minutes and it was pretty hard, no finger prints...but for you faint of heart with your best P-38, Mustang or Sabre on the line...wait the hour or more 8-).
I still recommend using the cloth or cotton gloves just to keep the grease from the potato chips you just ate off the model.
Any way this stuff is a lot tougher than the Testor's (a friend said not to let the apparent toughness fool you...it will still come off...so handle with care...and a soft cloth).
I masked with both the post-it notes and the low tack tape with good results, no peeling or marring.
The guy in the FSM article states that there are 3 levels of polish; first no polishing, this has a semi-gloss sheen, second is polishing with a soft cloth (or Q-tip), the third is achieved by placing some of the polishing powder that comes with the starter kit on the desired panel and polishing it in with a soft cloth (or Q-tip).
Ididn't get much shine from just polishing the sprayed on paint, until I really gave it a rubbing...none of this light wimpy polishing that works for the Testors *and* it was tough controlling the even-ness of the shine for this coat.
The final level with the polishing powder really makes the stuff shine - it looks like a mirror.
A side benefit that I accidentally found (when I was spraying grainy stuff every where and having to sand it off to try again) was that the SnJ makes a good filler/primer (tho a bit expensive for that).
I could see a couple of hair line scratches in the wing root of the test subject (a Monogram P-51) when I first applied the SnJ.
After a couple of episodes of grainy spray and cleaning off the paint...the scratches disappeared.
Again if you mess something up, just sand off the offending areas and reapply...can't see where the first coat was.
I tried using just the polishing powder to the recently sanded area (as the FSM article suggests) this works if you want the 'bright' polish on that area...otherwise just respray that area.
Again a little precaution and it is easy to get a good metallic finish with SnJ...not as many pit falls but getting that initial base coat on can be troublesome (at least for me).
Again none of the setting solutions seemed to affect the paint or the sheen.
I think the finish is hard enough that you won't even want to consider an overcoat.
And finally masking this stuff for additional colors is easy...no wet newspaper...regular low tack tape.
Summary: Either of the two paints will enable you to produce a good looking metallic paint scheme...and it's really more forgiving than regular colors...try to sand just part of an olive drab wing and then reapply...if you don't get different color shades, then you'll probably get ridges where the sanding stopped or a different texture.
I really like the base color of the Testors better than the base color of the SnJ (the polished areas are a tossup), but the SnJ gives you 3 levels of polish and you can't beat the toughness of the SnJ.
But then again there are more off the shelf colors with the Model Masters, but you can add gloss paint to the SnJ for various shades.
So I would guess if you are a bumbling fool (just kidding) like me, the SnJ gives you fewer places to make mistakes...short pickup tube in the paint jar and keep the stuff stirred up. If you are an expert (or just very careful) and don't have any kids (or handsy neighbors) around to touch the paint job then using the Testors would offer an excellent finish.
Good Luck on that Natural Metal finish.
P.S. Next I will try and summarize the lessons learned from Alcad's metallic paints (just ordered some last night).

Le informazioni proposte in queste pagine provengono da singoli modellisti, i quali, salvo diverse indicazioni, si esprimono solo a nome di se stessi e non delle istituzioni o delle aziende di cui fanno  parte. Gli autori e gli editori di questo materiale non si assumono responsabilità circa la correttezza delle informazioni fornite. I diritti per la riproduzione di questo materiale sono proprietà esclusiva dei rispettivi autori. Eventuali usi commerciali del solo testo originale in inglese necessitano di autorizzazione scritta dell'autore Don Schmitz  Don_Schmitz@transarc.com).
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