Painting buildings

[Planotrain]

I have several Piko buildings in my garden that stay out year round. Prior to this past summer I painted three of the buildings and placed them back outside. During the summer our temperatures exceeded 100 for many days. I just noticed that the paint is peeling off of the buildings I painted. I used Testors enamel paint recommended by hobby shop. looking for suggestions on how I can prevent peeling. I tried to lightly sand buildings. Maybe not enough.

[ttrigg]

Painting of any plastic structures:

1. When manufactures form the parts of any plastic structures the first thing they do is spray a "mold release agent" into the mold.  When they pull the parts out of the mold they trim the flashings (sometimes) then put it into the box.

2. Open the box then wash ALL parts (plastic and metal) to remove the mold release agent. The release agent makes it easy and quic for them to get the parts out of the mold. Mold release agent will "release" anything apply, to include paint, I don't care what kind of paint is used, release agent will allow the paint to "sluff off".

3. Washing, Hot water and liquid detergent, liguid dish soap, Mr. Clean, etc. I use 3 times the amount of detergent as reccommended on the package. Let the parts soak for at least 10 minutes, wash down using dish cloth, or bath wash cloth. While still wet rinse twice once ing pan and once in running water. Do NOT allow the detergent to dry as some release agent MAY stay behind in the soap. I use a final (3rd) rinse of "wetted water" ( quart of warm water with 3 drops of dish soap.)

4. When I want the smooth plastic walls to have an "enhanced" stucco look, I wash in turpinetine. Outside in nice breeze, wear rubber gloves! CATUION too much turp will melt some modles away, do it quick, do it light, do it again and again until desired texture appears.

5. First coat of paint, I use Krylon Fusion. Krylon Fusion is designed for outdoor platics and works extreamly well. It holds to plastic better than anything else. I use either a brown or black as a primer coat. My color coat will vary depending upon my desired final look. Sometimes exterior house paint, orther spary paints (Krylon has some very interesting colors) or hobby and/or craft paint.

I have 5 structures that have been outdoors for 7+(?) years. Yes, there is some sun fading but the paint is completely intact. MKy micro-climate: Sunny San Diego, no snow, little rain (until we get some, then we get a BUNCH), lots of sprinkler spray, Dogs hiking hind legs, chickens taking "target practice".

I would suggest scraping off the existing paint as release agent is under it and it will fall off sooner or later. Then wash as above. Scraping should maintain any existing fine detail features. Sanding will rmove these fine details.

LAST POINT: Mold release agent will also RELEASE GLUE!!!!

 

Sorry about being long winded.

[ttrigg]

Follw up point: If a plastic UNPAINTED buliding has been outside for a while, the top "molecular layer" will have "oxidized/UV damage". (OK, completely wrong words, but you get the idea.) Wash the building as above to remove this "damaged" layer and any remaining release agent. Release agent will surivive outside for several years, unless you have LOTs of rain.

[ttrigg]

SAFETY TIP: When "washing" with turpintine, the rags used CAN self ignite if not properly disposed. I use shotgun cleaning patches, then when finished I put into my patio fire pit and burn. I have had them self ignite from improper disposal.

[dwbeckett]

That is the same way I prep and paint both rilling stock and buildings with very good sucess. I use primer on some, make that most of everytning I paint  it helps the paint stick better. the primer also helps if you want to change the shad of color you are useing. darker primer/darker color, lighter primer/lighter color and on occashion i use just primer.

Dave

[St Francis Consolidated RR]

     Holy smokes Tom...thanks!! I just printed out that whole process and am keeping it safely tucked away for future reference!

[ttrigg]

Just passing along a lesson passed on to me 40+ years ago. Clean before painting.

[wernerjp]

I live along the coast of SC where the summer heat and humidity are brutal.  I paint my outdoor "plastic" buildings with Valspar spray paint from Lowe's.  There is no sign of peeling, etc. after 4 years in my garden railroad.

[kstrong]

I've never gone though any hoops to clean buildings prior to painting, save for washing the dirt off of them if they were purchased used. I've never had any trouble with paint peeling or not sticking. I don't know why my experience is different from Tom's--lucky I guess, or maybe a difference in the mold release agents used by different manufacturers. (Also, check to see if the plastic has been painted at the factory. If it has, they've taken care of the cleaning for you.)

I've always used exterior-grade paint--either spray or latex from the can. Sprays are certainly convenient if you're painting prior to assembly. I've lost a bit of faith in Krylon since they "reformulated" a few years back. Their new stuff hasn't performed quite as well for me. I've not tried their "Fusion" line, but I think Tom's the first person who I've read has had positive results with it. I like Val-Spar (sometimes sold under the "American Traditions" brand), as they have a line of colors that matches common building colors of the early 20th century. For latex out of the can, I use what I have around the house, or occasionally check the "goof" shelf at the local hardware store for colors of paints that could be useful. You can usually pick those up rather inexpensively. (Also, most stores will mix you up a small pint can as a sample for a small fee. A pint goes a L---O---N---G way in miniature, and is still cheaper than buying the jars from the hobby shop.

That's one thing I would definitely NOT recommend--hobby shop paints for outdoor buildings. They're just not designed for exposure to the elements. Some fade very quickly, others peel. Litmus test--if you wouldn't use it on the front of your house, don't use it on your buildings.

Later,

K

[Southwest Chief]

kstrong

I would definitely NOT recommend--hobby shop paints for outdoor buildings. They're just not designed for exposure to the elements. Some fade very quickly, others peel.

 

I've painted several G scale buildings with Polly Scale paints, specifically D&RGW Building Cream and D&RGW Building Brown.

 

All have held up very well.  However the key is to add a top protective coat.  I like Krylon Matte Finish.  Dulls down shine and protects the underlying paint very well.  it also protects decals pretty well.

I use Krylon Matte Finish for all of my G scale top coats.  I've used it on structures, rolling stock, and vehicles.  If you need a gloss finish for the final coat, you can use Krylon Crystal Clear.