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lacquer coverage problem


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That's a general title, for sure.  I'm trying to generate a solution to a problem I'm seeing when doing a Tamiya rattle-can finish.  The immediate problem is typical, the colors change but the problem does not:  White primer on a gray plastic airframe.  Follow with color coat (yellow!).  Results: color coat melts into its primer and leaves the plastic showing around sharp edges, like aileron cutouts and elevator/fuselage joints.  No amount of recoating will cover those joints with yellow, gray always shows through.  And primers are nearly always lacquers.

 

Ideas, solutions, experience?

 

The only way I've had some success is to use a dissimilar primer that the color can't eat, like waterbased acrylic.  My problem with that is the only rattle-can acrylic primer I have is a rapidly-diminishing can of Humbrol.

 

Thanks!

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Gloss yellow and white need very thin coats, a lot of very thin coats, to build color coverage before a heavier final gloss coat. I use an airbrush to accomplish this, so I'm not sure how to achieve this with rattle cans. 

 

With gloss white, you can use a white primer to speed this up, but I'm not sure what to do with yellow...

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1 hour ago, peter havriluk said:

 Results: color coat melts into its primer and leaves the plastic showing around sharp edges

 

You're spraying too thick a coat.  Use multiple light coats to gradually build up the paint colour, wait a few minutes between coats to give the paint a chance to start drying, and once you have the right colour, finish with a slightly heavier coat to level out the surface.  It will take some practice to get a feel for the exact technique, so you might want to practice on an old, junk model.

 

You should also give your primer longer to cure.  If you can smell any paint on your model, the paint isn't cured.

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Thanks for the insights, folks.   I'll have any number of opportunities to work this out (185 in the stash).   I can see how I was having problems with the colors that don't like to cover.  Heavier applications look to be making my discomforts worse.  I do let my primers cook off overnight.

 

Much obliged.

 

And who doesn't like Woodie Guthrie!

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Peter

 

Share some photos of your results, we can post-mortem examine the results and possibly give better advice.  Advice given here I think has been correct, but blind without photos.

 

If you have 185 in the stash, I'd be considering getting an air brush.  Lots of free video's on how to maintain, clean and use an airbrush.

 

Also, if you are using lacquer based products, either way, use a good quality respirator or be outside in breezy conditions.

 

 

Edited by Jonathan S
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For real, if you're building 185 kits, the amount you will spend on rattlecans will pay for the airbrush, compressor and some paints.  

 

I held off on getting an airbrush for many years.  I'm so glad I took the plunge when I got back into this last October.  So much more enjoyable... and as a bonus, I now have an airbrush for various other, non-modelling projects... like painting the inside of headlight assemblies when re-building/modifying headlights for friends.  

 

 

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I've had airbrushes of varying sorts for thirty-plus years.  And a dedicated compressor.  They perform beautifully, all of them.  What they don't offer is convenience and are great consumers of time.  Setup and knockdown/cleaning takes vastly more time than that is spent applying paint.  And they don't make any more time.  

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If these are indeed true lacquers, every subsequent coat is a solvent for the underlying layers.  Lacquer paints actually dry ... in other words ... they get hard due to the evaporation of the solvent.  Application of additional coats will soften your underlying layers.

 

If you want to gain some understanding into paint types ... give my page about paints a read ... http://paulbudzik.com/tools-techniques/Airbrushing/paint.html

 

paint_world2.jpg

 

Edited by Paul Budzik
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Paul, They sure behave like lacquers I've used in other applications, and their behavior is as you stated.  I've done a fair bit of lutherie, and lacquers are common finishes just for the characteristics you mentioned, that of the last application  'burning in' and fusing with what is beneath, leaving no discernible layers. 

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