How do you prepare the plastic model for painting

dfandrews's picture

I've just starting using water-based paints instead of my old standard:  Floquil.  From all I've read concerning acrylics, there is great emphasis on washing in detergent and water.   (I've usually used solvent alcohol to remove oils.)  My concern is not so much with solid structures like buildings, but with fragile structures like bridges and towers:  anything that is more truss than solid surface.   I'm getting quite a line of projects on my shelf, that need paint.

So the question is:  What do you do to prepare models for painting?  Problems?  Cautions? 

Preparing plastic models for painting.

It is always a good idea to wash plastic with soap and water. Dish washing liquid is usually a good idea because it makes water weter and allows the removal not only of the geasy stuff that comes with the molding process but also the stuff your hands leave on the surfaces. It would be a good idea to use rubber gloves when handling the plastic aftre washing as well as there willl be little of the natural oils yor skin leaves on the dried parts that way.

As for painting, I would suggets you paint before you put the parts together as you may not be able to reach all of the spots once the kits are put together. You can then use either a hand brush or an air brush. If yu want an even color, you'll usually need to use and air brush. However, if you intend to weather the kit, you can got resuts with a standard paint brush.


Mike Martin's picture

I was always....

I was always taught to put the model together and paint it last then decal and weather. Then again I guess it depends on if your spraying or brushing. If your brushing the technique may be different.

Mike Martin

Joe Brugger's picture

PollyScale Plastic Prep

Plastic Prep does a good job of lifting oils and mold release off of plastics and is reusable; you can run it through a coffee filter to keep it fairly clean.  A good 10-20 minute soak followed by a warm water rinse is usually enough.

If you use dishwashing liquid buy the cheapest stuff -- some brands have lanolin and other additives that will do your paint job no good at all.

91% alcohol also works but you need to rinse it quickly before it evaporates and leaves all the gunk back on the surface. It also gets a bit heady in a closed room.

Rio Grande Dan's picture

Dawn dish soap is the best as

Dawn dish soap is the best as it removes almost all oil and grease.

You should soak the pre-assembled plastic Model parts in the Dish soap 4-8 drops in a1/2 gallon of warm water for 10-12 minutes and then rinse in clean warm water and allow to air dry. Then depending on the type paint your using you may want to use "Barrier" if your using oil base enamel.

Polly "S" makes a product called plastic prep #546007 it's a pre-painting cleaning agent for plastic surfaces you use it after the soap and water wash to remove any remaining mold release,Silicone or grease & oils still in crevices and again allow to air dry before painting.


Rio Grande Dan

dfandrews's picture

Thanks to all

Thank you, all of you, for the great tips.  Just the information I was looking for.


Rincon Pacific Rwy, 1960.  HO scale std. gauge - interchange with SP.


How do you prepare the plastic model for painting

I've read to use liquid laundry detergent. No lanolin and will clean the oils and release agents from the plastic as well as the dishwashing liquid.

Thoughts on vinegar

What is everyone's thought on using white (distilled) vinegar. I first came across this building an older roundhouse steam engine. The instructions said to clear the parts in white vinegar. It seamed to do a good job, but nothing special.


JC Shall's picture

Etching the Metal

I believe folks use vinegar on metal models because it's thought that it acts as a mild etchant to the metal, giving it a bit of tooth.  The paint should adhere better to the model.


Effect on decals?

If the model already has decals applied, would washing it in Dawn soap and warm water have any ill effects? Vinegar? Isopropyl alcohol?

DKRickman's picture

Yes, maybe, no

Assuming that you have properly set the decals with setting solution, I think that a very gentle washing would be safe.  I cannot imagine why you would want to use vinegar, but I would not recommend it unless you're tried it on a sacrificial model and found it safe.  I would definitely not use alcohol.  Just this morning, I began stripping a previously painted model in alcohol.  Since there was no clear coat, the decals came off easily after soaking in the alcohol bath.

Two thoughts.  First, I would always suggest leaving the decals off until you can complete the paint process and will not need to handle the model.  Second, if that is not possible, or after the decals have been applied, I always suggest a clear coat of some sort to seal and protect them.

Ken Rickman

Danville & Western HO modeler and web historian

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