Weird old plastic/spray paint issue

First bravo for doing a seaplane, my Pa loves ya.

When paint will not stick, it's generally one of two reasons Either there is something on the surface, or a chemical reaction with the surface. It should be OK using oil based paints, but if not, try a good primer like Mr. Surfacer, or Tamiya primer. Or... the plastic still might be outgassing, causing adhesion problems for ya.

BTW, Krylon is not ideal for plastic IMHO. It is *hotter* than normal paints we use, that could also be the problem. Matter of fact, I would try another gloss white and see what happens. Also, Krylon has pigments that are not as finely ground as with what you will get in most model paints.

Orange peel, and fisheye are generally the results of temp and humidity problems. (or too heavy an initial application) Look closely and see if it really is orange peel you are looking at and not just the *lumpier* paint of Krylon.

I've never had good results with Krylon. so again, first thing I'd do, is clean the affected areas, and than try another type of primer/paint and see what happens.

Alas, I almost always prime my models with good primer, sand/clean and than finish coat.

Remember, with paint, less is more. Ie; as thin a coat as possible ALWAYS, and than go back and coat again if necessary.

Let us know how it goes :)

It could be lumps in the paint or it could be the paint is etching the clear plastic. I've never shot Krylon on clear plastic so I have no experiences with that but usually Krylon works well for me on opaque plastic. And, I've had no yellowing yet like I get with Testors.

Bill Banaszak, MFE Sr.

Curiouser and curiouser...

Figured, "ah, to hell with it!" and went on with the kit. Masked well, sprayed over with gloss Dark Blue Tamiya (TS-55). HOLY BUCKETS!

Anywhere that there was no plain plastic it crinkled like with enamel and lacquers! The Krylon is for sure Enamel, no doubts, I only use enamels for brush paints, and even where there was exposed putty from the finishing it did the same thing.

I think I'm fighting two things here, old crappy clear plastic, and weird Tamiya spray paint.

What say you?

-andyh

Tamiya Spray paints are synthetic lacquers . . .

I use Krylon Gloss White and have had a problems since the chemical change for (as Krylon told me) enviromental and changes to the allowed ingredients by law. I will throw in what I know and see if this is any help to you. The responses before mine have great info on your problem so if thier help does not get you to the needed paint finish, here a few tips / pointers that I use.

1. First find out which Gloss White you are using. The (NEW) Gloss White is called Indoor/Outdoor OR the (OLD) Gloss White which is called Interior/Exterior.
2. Find like materials, styrene/plastic/foam/metals and do tests. Like thick coats, masking with different tapes/plastics, dry times, number of coats ect this will show most all types of defects from painting. I know this is tedious and may not fit but it has saved me many times.
3. Now to 'orange' peeling with these paints. The reply about cleaning is the biggest for this problem. There are some styrene and plastic in my rides and I have found this to happen with both Krylon old and new gloss white but the reasons are different.

A. With the Old paint it was from bleeding the chemicals out of the material being sprayed on. To get the finish I needed it took a little thin coat of clear finish spray or brush for small areas. Let dry

24-48 hours then spray as usual. I have tryed this EASY method with the New and I just cannot get that great finish I want. For you this may be enough. Test and see.

B. With the New paint it is from breaking down the materials period. (this has been very hard for me to solve) Although I have got by with a few techniques.

B1. * For small pieces and even some medium parts. I spray the Gloss White in a suitable container with a lid (fold an old xmas card and spray can upright onto card and let paint run into container. REMEMBER to use the none printed side or it will bleed into paint. Spray just enough for the job into the container. I put paint into an old plastic film container 35mm. I let it sit with lid not closed just covering it for 1 day then apply paint with Q-tip or paint brush USE heavy amount s so brush strokes won't be visable. Then close lid and you can reuse for about 1 week before it starts to clump or dry. This is how I do most all my Gloss White where your perticular problem can happen. (This works GREAT for OLD Gloss White as it was my bread and butter to painting scale rides)

B2. For Large areas where hand painting is just not an option. As already mentioned in another reply HUMIDITY / TEMPERATURE and spray painting are to be watched closely these can make or break a paint job. Coat area liberally in a ventilated area (I put a fan on the area before I start and Keep air moving over the paint job through out) but not to the point of the paint running "watch the clock" at about 10 minutes (this is another place where testing comes in so useful) spray a light coat or coats(every 10 miutes) to get desired finish. This way is not 100% but I do get some great finishes on the rides where pitting or orange peeling can happen.

B3. If none of this works. I have put materials in freezer to get it cold then did B2. Or just paint at about 50 degrees and LOW humidity with fan on the job.

C. Some other tips are: Krylon and masking tape are real tough to get good finish lines with. If left on over a few minutes the Krylon will bleed the tape chemicals and/or coloring into the paint. If left on to long it will peel paint with it on removal. I often use the Q- tip/brush method to do edges then spray the large area by masking(blue Ace Hardwear for me works best) on the alreay painted white area (B1). It's tricky to get the great finish but a few test runs on samples I think you can get quite good at a great finish.

D. The Old and New Gloss White CANNOT BE MIXED or painted on top each other in any combo. Many many problems occur, bleeding, peeling, flacking, bubbling ect ect. At first I hated the New Indoor/Outdoor Gloss White but once I got B1 to an art I actually have finally after near 1 year quit stopping at every paint store hoping to find the Old Interior/Exterior can on the shelf.

Hey hope this helps or at least gets you thinking of a way to save the plane.

*much snipping*

WOW! Impressive! I have to give major kudos for your research. This is an article that I'll be holding onto for a while.

What I've found: It's a chemical reaction between the paint and the clear plastic. I tried wiping down the clear sprue tree with alcohol and spraying a bit of it with the gloss white, same thing. Tried it with flat black Krylon, no problems. I took a closer look at the gloss white bit and found that it wasn't just the paint 'orange peeling', but it was actually etching into the plastic and causing it to look like a very tiny mud flat.

I've given up on the clear parts, the destroyed bits would require so much re-working that it isn't worth the effort. Now that I know what's going on with the Tamiya spray paint I can do what I can to fix that as well.

It's so weird that Tamiya has enamel bottle paints in the 1/4 ounce, but Lacquer spray paints that match the colors perfectly. The enamels brushed over the spray look just fine, so I'm touching up the bigger areas. It just won't look as good.

The final result is that it's not going to be sitting on my desk in my class-room, it's going to be hang- ing from the ceiling in my apartment...

Thanks for all of the help guys!

-andyh

OMG! All this research and tests? Why not just use plastic compatible paints?! Krylon was never designed to be applied to polystyrene but some of you were just lucky.

DUH! Peteski :-)