Sources of Plastic for Testing Paint

[Miatatom]

I'd like to find a cheap readily available source of plastic to test paints for compatibility and just practice spraying with an airbrush. I don't have that many extra kits to just sacrifice for that purpose. What do you guys practice and test on?

[Snake45]

1. Boxes of cheap plastic spoons. 

2. Yard signs, like FOR SALE and that sorta thing. Cheap, but not guaranteed to be kit-grade styrene. 

3. The underside of interior tubs and the topside of chassis of kits--along with, of course, sprues. 

[Rob Hall]

Plastic spoons, and customizing parts from AMT kits that had them...custom hoods, pans, etc. 

[randyc]

Old bodies, spoons, plastic styrene sheet (check with a sign company?).  For compatibility, you really should use plastic out of the kit.   You can usually try that on the top of chassis if kit has a separate floor pan that will cover it.  Or on the bottom of chassis if you are going to paint it anyway.   So what if it isn't glossy?  It can give you and idea of paint will work on a particular kit's plastic.

For general practice, get some signs at Walmart or something - like the FOR SALE or NO TRESPASSING and paint the backs.  they may be slightly textured though, if they  are PVC.   But I think some are styrene.  Or find a sign supplier near you and ask for scraps of styrene sheet.  Heck, a 4'x 8' sheet used to be less than $10 for 1/32" or so.   I have an inch tall stack of plastic squares we had when we cut them up for gas pump overlays.  

Look on ebay for junkyards of plastic parts that are still unpainted?  

 

[Miatatom]

I'm looking for something larger than sprue or spoons for practicing spraying. They'd work for testing compatibility though. May buy a few signs and see how they work. Thanks, I'd forgotten about them.

[Bucky]

A good for compatible plastic is the sprue, or extra parts from the kit you're planning to build. Otherwise, plastic spoons are what a lot of builders use.

[Miatatom]

2 minutes ago, randyc said:

Look on ebay for junkyards of plastic parts that are still unpainted? 

Good idea! I'll look.

[randyc]

I sold a whole box of bodies to a guy.   Some other guy gave them to me.  They are out there.  Happy hunting.

[Mark]

I've picked up NASCAR kits for a buck apiece...

[Bucky]

I have one old scrap kit body that I've painted about five different times for practice, and to check color shades with different color primer underneath. That scrap body can always be stripped back to bare plastic, if needed.

[BigTallDad]

Soda bottles work too.

[Ace-Garageguy]

1) For the hundredth time...plastic spoons, signs, and Evergreen / Plastruct are NOT the same as kit plastics, and are typically made from styrene compositions that are in fact very different from what kits are made from.

For testing compatibility of materials with kit plastics, it's essential you use plastic from the kit you're working on...because not all kits are made from the same grade of styrene, though the term is used to include them all.

The suggestion about using the undersides of chassis or interior parts that will never be seen is a good one.

2) If you don't have spare or junk bodies to use to just practice your spray technique on something about the size of a model car body, and that requires moving around a 3-dimensional shape and learning to control spray-pattern overlap and prevent runs, a plastic "Coke" bottle works very well. Scuff and primer it, then spray away.

3) Testing color effects and paint material compatibility with other paint materials can also be done effectively with plastic bottles. But bear in mind that some materials WILL behave differently when you shoot them over a specific kit than they did during testing. I very recently had an adverse reaction over PARTS of a largely scratch-built and complex kitbashed chassis, where I'd neglected to test my materials over every different source material.

[Tom Geiger]

white plastic spoons are good because they are curved so you can see how the color will look over model body curves.

A lot of guys will test not only for compatibility between say  primer / base coat / clear coat,  but will also experiment with different primers and under coats to achieve different results.

[SfanGoch]

What Bill said. Different styrene mixtures react differently to different types of paints. Spoons might give you a nice look after applying paint; however, it's made from something completely, here's that word again, different than was used in the manufacture of a particular kit. Using runners (the sprue is actually that circular mass in the center of the parts tree) will provide you with the best info as to styrene-paint/solvent compatibility.

[935k3]

Another issue I have had with spoons is some hot paints craze them and this makes it impossible to see how the lay down.

[Miatatom]

53 minutes ago, 935k3 said:

Another issue I have had with spoons is some hot paints craze them and this makes it impossible to see how the lay down.

Spoons have always been misleading to me. I can paint a spoon and it'll look perfect. If I was building model spoons, I'd be the painting champ! ?

[MrObsessive]

Incompatibility issues with today's plastics is yet another reason I'm a big believer in putting some kind of barrier coat over the plastic BEFORE painting. Particularly since the mid '00's, there's been a definite change in the plastic in regards to how they react to even model paint let along automotive ones.

It's a bit more work, but a long standing pet peeve of mine is doing entire paint jobs over again.

[Miatatom]

2 hours ago, MrObsessive said:

Incompatibility issues with today's plastics is yet another reason I'm a big believer in putting some kind of barrier coat over the plastic BEFORE painting. Particularly since the mid '00's, there's been a definite change in the plastic in regards to how they react to even model paint let along automotive ones.

It's a bit more work, but a long standing pet peeve of mine is doing entire paint jobs over again.

What do you use for a barrier coat?

[MrObsessive]

1 minute ago, Miatatom said:

What do you use for a barrier coat?

This here...........GOOD stuff for any plastic. Put on dusting of primer coat and then put on the BIN Zinnser. Prime again with your choice of color and NO issue with bleed through or crazed plastic.

You'd need an airbrush though.........no thinning is needed if mixed thoroughly in the can.

I did this Viper using the sealer as that was one of the kits that had an issue with "soft" plastic.

[Miatatom]

Thanks, Bill!

[peteski]

As it has been mentioned, there are 2 reasons for testing paint.

1. for compatibility with the plastic model

2. to learn how to apply smooth finish.

Number 1 has been covered.  For number 2 one can use plastic bottles (in all sorts of shapes and sizes). Yes, I know that has been mentioned, but I'm just reiterating it. Speaking of this, I wonder where Alclad got those fluid-looking shapes they use in photos demonstrating their paints (on their website). Those would be ideal for practicing airbrushing model car bodies.

[SfanGoch]

They are called speed shapes, car shape test panels or aeroforms. one source is Paint With Pearl.

[peteski]

15 minutes ago, SfanGoch said:

They are called speed shapes, car shape test panels or aeroforms. one source is Paint With Pearl.

Cool!  they are just about the right size for 1:24 model body, and at 3 bucks a pop are also affordable.  Perfect for practicing spray painting!

[ChrisBcritter]

Ask around for leftover AMT Masterpiece Series pen and pencil set bases - they're nice big rectangular pieces of kit styrene.

[Dave G.]

On 10/21/2019 at 10:56 PM, peteski said:

 

1. for compatibility with the plastic model

2. to learn how to apply smooth finish.

 

It's also helpful for testing new colors you never used or new paint lines you never used for opacity and dry times, and for what color primers and base coats you want for a paint scheme you had in mind. I've found huge shifts in color depending on if the primer is white, mid grey, dark grey or black in seemingly opaque paint that evidently wasn't so opaque. I've come to making a test before shooting each body unless I've already used it and know the combo well.

I use pill bottles, large and small since I have a bag full of the things ( regular pharmacy amber prescription bottles). For bigger tests I use plastic cups, actually the same cup I mount my body to when I spray the car body. I found those to behave similar to most model car styrene ( maybe not resin, and your local supply may vary lol). I tried some plastic plates once and those were terrible, everything basically fish eyed on them.