Saturday, April 23, 2011

Top Coats related FAQs

What is Top Coat?
It is a transparent coating sprayed on top of the paint.

Why do I need to spray Top coats?
Top Coat is used for the following reasons:
1.  Protect the paint.
2.  Seal the decals.
3.  Give the model kit the desired finishing.
4.  Slows the yellowing of unpainted model kit.

What are the different types top coat finishing available?
1. Matt/ flat : This kind of finishing diffuses light and no reflection can be seen.
2. Semi-gloss: Some what between Gloss and Matt finishing. Slightly Glossier than the original plastic.
3. Gloss : Pretty much like a car finishing, highly reflective or sometimes like mirror finish.

Should I apply Top coat to my models if I only panel-line but not paint them?
It is not necessary, but Top coat will slow/prevent the plastic from yellowing. Flat top coat applied on a unpainted model also makes it look less like a toy.

When should I apply Top coat?
Generally, Top coat is applied as the last / final coat.

Is it necessary to apply a layer of gloss top coat before applying decals?
Unless your paint finish is very rough, you do not have to apply a layer of gloss top coat before applying decals. The gloss top coat is to provide a smooth surface to make it easier to position the water-slide decals. Note of caution, if the coat of gloss is applied is too thick, the decal may appear to be floating.

Is it necessary to apply a layer of gloss top coat before doing panel-lining with enamel paint?
Unless your paint finish is very rough, you do not have to apply a layer of gloss top coat before doing panel-lining. If the surface is too rough, it may be difficult to clean of the excess enamel paint.

Why do my panel line smudge when I apply Gloss top coat?
Panel lines are usually done with markers or enamel paints. The solvent from the lacquer Top coat may dissolve the panel line paint, if too much top coat is applied, Apply a thin layer of top coat first, allow one day for the Top coat to cure before applying a thicker second layer.

Why do certain area of my model kit turn white (frosting) after I applied the Flat Top coat (Spray can)?
You probably applied your Flat Top coat when it was humid , like rainy days or at night. The spray reacts with the moisture in the air to create the 'frosting' effect. Although the effect on the semi-gloss and gloss Top coat is not as drastic as the Flat Top coat. It is strongly advised that you apply you Top coat on a Hot and Sunny day.

I can only work on my models at night. Is there a way to apply my Flat Top coat at night?
You can try warming you the can before use by placing it in warm water (not Hot water), it should reduce the chance of frosting, but this method is not guaranteed. Another alternative is to apply Top coat using airbrush, it does not produce frosting effect. 

Added on 10-May-2011
What can I do if my Flat coat "frosted"?
Several Remedial Actions
1. If you own an Airbrush set, you can try to dissolve the frosted area by spraying lacquer hobby thinner, eg. Mr Color or Gaia paint thinner, not industrial thinner (Thinner you get at the hardware store).

2. If you do not own an Airbrush set, you can spray gloss topcoat over the frosted area to remove the frosting. Apply in moderate amounts, or else the top coat will look unnaturally thick.

Alternatively, you can wait for the Flat topcoat to completely dry and cure before sanding lightly with 1000 grade sandpaper to remove some of it. If you cannot remove all the frosting, spray over the remaining frosted area with Gloss topcoat.

 If the topcoat is sprayed over unpainted plastic with no stickers or dry transfer, you can try applying Mr. Color or Gaia thinner with a brush over the frosted area to dissolve the topcoat and wipe it off with a tissue / unwanted cloth. This method can be fairly messy and not advise unless all other options are not available. (Although Mr. Color and Gaia thinner are not suppose to melt plastic, but it may cause the plastic to become a little more brittle.)
Last Edited on 10-May-2011

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