One of my modeling projects currently are a set of coal hoppers, getting new paint and decals. (This was a undecorated model from old stock I have had in preparation for this project.)
My model pre-painting prep was:
1- Scub with soapy water using old toothbrush.
2- Rinse with distilled water then let air dry.
3- Remove any remaining fingerprints using a lint free cloth dampened with rubbing alcohol. Then let air dry again.
4- Place in spraybooth (using gloves) and do a light coat of black gloss paint. (Modleflex.)
This is what the first coat did....
Paint issues? by Richard W, on Flickr" alt="Paint issues" width="375" height="500" />
Any ideas on what I did wrong?
Ambient temperature was ~70F, and humidity was low.
Airbrush was set to 30PSI, and sprayed ~ 6-8" away from model.
Ricky W.
HO scale Proto-freelancer.
My Railroad rules:
1: It's my railroad, my rules.
2: It's for having fun and enjoyment.
3: Any objections, consult above rules.
I can't see the image, but step 3 seems a bit odd - never heard of using alcohol to remove fingerprints after washing the car? If the paint didn't adhere properly, I'd guess it reacted to the alcohol on the car. Putting alcohol on the car kinda defeats the purpose of washing the car.
If you're really concerned about fingerprints, use rubber gloves when washing the car. I usually just soak the car for a while in warm water with a little soap, then run it under a cold water spray in the kitchen sink, then let it air dry overnight (maybe using a soft paper towel to blot some of the water off first). I use a paint handle so I don't have to touch the car after it's mounted on the handle.
I am also unable to see the picture.
-Kevin
Living the dream.
Let me retry the picture...
Paint issues? by Richard W, on Flickr" alt="Paint Issues" width="500" height="375" />
Just incase it doesn't show again, here is a direct link....
https://flic.kr/p/2j3zVjN
There is "pitting" but not everywhere, just some locations. Almost makes me wonder if I somehow missed some mold release or something...
When I enlarge your picture, I see what mean by pitting. Almost looks the paint didn't stick to those areas.
Something on the plastic?, too thick of a coat?, something with the paint?
I dunno Rick!
Mike.
My You Tube
I've not seen that problem before, so am at a loss to explain it.
I've had very poor results using ModelFlex paint, though, and got rid of mine years ago. I do question your cleaning regimen, though...a short soak in fairly warm water and dish detergent, followed by a thorough rinse with tap water should be sufficient for cleaning. I let things air-dry, usually overnight, in a dust-free environment, and use nitrile gloves or, for tank cars, a holder during airbrushing.I use toothbrushes for paint-stripping operations - if yours was also used for that, perhaps there was enough residue of stripper left on the brush to cause the apparent pitting. I agree that the alcohol after cleaning may not have been a good choice, but I doubt that it caused the pitting.
Unless you're planning to cover-up the results with some fairly heavy weathering, I'd strip-off the paint, which might reveal if the "pitting" is in the paint or actually in the plastic.
I'd also think that 30 psi is too high for acrylic paints, so check the manufacturer's recommendations.I made the same mistake when I first used acrylics, and had terrible results, despite following advice from several modellers on this and other forums. I finally went to the manufacturer's website (for Pollyscale paints) and saw the recommendation to spray at between 15 and 20 psi, and have not had a problem since then.
Wayne
The PSI is the reccomended preasure by Badger for the Modelflex paint. (http://www.badgerairbrush.com/PDF/ModelFlex%20032613.pdf 25-30PSI note under 4A) so I didn't think anything of that.
I was not planning on too much weathering on these (representing a recently redone car on the 1:1 for my modelling era.) so I will be stripping and repainting, but was wondering what happened to avoid it reoccuring.
Maybe I will try skipping the alcohol wipe down, just incase that is the issue...
Thanks everyone!
ricktrains4824Maybe I will try skipping the alcohol wipe down, just incase that is the issue...
Was the bottle labeled "Rubbing Alcohol?" Sometimes I wonder about the purity of discount store alcohols. Anything sold in the pharmacy section may have oils or scents added. I may use 99% isopropyl as a step in a degreasing process if necessary but my final wash and rinse is a good-quality dishwashing soap followed by a warm water rinse.
As Wayne states, from that point on I don't allow my bare fingers to touch the surfaces to be painted.
Good Luck, Ed
gmpullman ricktrains4824 Maybe I will try skipping the alcohol wipe down, just incase that is the issue... Was the bottle labeled "Rubbing Alcohol?" Sometimes I wonder about the purity of discount store alcohols. Anything sold in the pharmacy section may have oils or scents added. I may use 99% isopropyl as a step in a degreasing process if necessary but my final wash and rinse is a good-quality dishwashing soap followed by a warm water rinse. As Wayne states, from that point on I don't allow my bare fingers to touch the surfaces to be painted. Good Luck, Ed
ricktrains4824 Maybe I will try skipping the alcohol wipe down, just incase that is the issue...
I agree with Ed. Rubbing alcohol is not the same as plain old regular garden-variety or pure alcohol. It might contain glycerol or oils or surfactants or scents or other things besides pure alcohol.
Robert
LINK to SNSR Blog
Hello All,
A maker of resin shells recommends NOT using the dish soap and water method for paint prep of his products.
He recommends using either lacquer thinner or mineral spirits to soak the shell(s) and then, using gloved hands, remove and allow the shell(s) to air dry before painting.
For the shell I got from him, I used the dish soap and water method along with a final rinse in 91% isopropyl alcohol and air-dried.
The difference was I used Rust-Oleum, 2X Painters Touch, rattle can paint. This supposedly "bonds to plastic".
Other than a few ripples in the paint, due to my errors, the paint dried smooth and did not cover the fine details.
After stripping the paint from the shell you are working on, you might try the lacquer thinner/mineral spirits for paint prep.
Hope this helps.
"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"
jjdamnitA maker of resin shells recommends NOT using the dish soap and water method for paint prep of his products.
Resin, completely different material than poly-styrene that the OP is working with.
jjdamnitHe recommends using either lacquer thinner or mineral spirits to soak the shell(s)
Lacquer thinner will turn a styrene shell into mush almost instantly. Get two foam coffee cups and put some Dawn dishwashing soap in one and lacquer thinner in the other and ask yourself if that's what you want to dip your styrene shell into?
Cheers, Ed
Was the model stripped to undecorate it or did it come from the factory unpainted?
In the more glossy panels I see what I think might be residue around the ribs from an incompletely removed layer of paint.
Mark Vinski
Common problem spraying acrylic paint on a contaminated surface. Something that does help prevent this is to hit the car with a tack coat first. This is a light dust coat that doesn't require the paint to flow. It will provide a more even coverage even over slightly contaminate areas that would normally prohibit paint flow. After a couple tack coats, and allowing them to kick off, you should be able to them hit it with a wet coat. The tack coats will help the paint to flow over any contamination left behind.
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
When you blow the picture up, it looks to me like something on the surface was reacting with the paint to create the problem. Notice how the two upper end panels are much less affected, as if they were rinsed better before painting.
It's hard to tell for sure, but the paint also looks pretty thick, though I doubt that contributed to this issue.
It was undecorated from the factory. (I have 4 undecorated from the factory, with 8 others I am stripping slowly. [I found the ones I am stripping dirt cheap @Berea train show last fall.] Have two stripped, and this was the first undecorated one I have assembled enough to paint and decal.)The "rubbing alcohol" bottle is a bottle of leftover 91% Isopropyl from a different project. (In fact, it's now soaking in the remainder of that to strip the Modelflex off.) It is (supposedly) only Isopropyl and water.
Could it have been a soap issue? Due to the very hard water in my area I used distilled water for the rinse, but maybe that didn't get all the soap? (Last time I used tap water on a model it left mineral residue that had to be removed prior to painting.)
Maybe rinse with warm tap water then the distilled water to remove the mineral residue?
Just odd, I've used acrylics for quite a while for stuff and never ran into this... That's why I posted the pics, to see what I did wrong. But I was kinda thinking that it was a prep issue with some kind of contamination on the model reacting with the paint.
Thanks for the help everyone!
Rick, I'm very fuzzy on this, but I sort of remember not too long ago using some alcohol to clean some styrene for painting with Modelflex and got the same kind of reaction that you got. I sort of remember being instantly disappointed that happened while the paint was wet. I immediately cleaned it off and reshot it.
At age 85 things I don't retain details very well, so it just sort of came drifting back to me. I certainly don't want to start a rumor that the two don't mix, but I am enough concerned that I won't use the combination again. If correct, it has to be a residue, as the alcohol would quickly evaporate. I just checked the bottle and it's 91% isopropyl.
One thing I might add, I suspect Dawn dishwasher soap might not be a good choice. I've used it to clean my glasses and also have it in hand washing dispensors. It seems to be hard to get the residue off my glasses completely. It's a great soap for it's intended purpose and a very good oil and grease remover, but for painting purposes, I'm suspicous of it's residue.
No experiene with Modelflex but the picture reminds me of a paint I thinned too much and got areas of paint and areas of thinner. Don't remember which paint, but it was an acrylic.
Henry
COB Potomac & Northern
Shenandoah Valley
I think I'm confused. Are we looking at the black or the silver. I was looking at the silver where the pitting is. What's wrong with the black?
Too thin?
I only added a drop or two of Flow-aid, which i had cut with distilled water, so it shouldn't have affected the paint that much... (I have a old paint jar that i put distilled water into, then added a few drops of flow aid into, that I pull just a couple of drops from when I put the paint into the airbrush cup. As I have several cars for this paint, I transfered the paint to a airbrush jar that can be either on the airbrush, or sealed with a lid, and added just the couple drops to it, so it was almost half the jar of Modelflex with just the couple drops of wet water added.)
And it is actually black, the silver is actually the light reflecting back from the gloss of the paint I think... Or the iPhone camera just is making it appear "off" color wise. (Looking at the pic again, I think it's a combination of both. The "black" looking area is just shaded by the phone from the room overhead lighting.)
I have it stripped back off of the model, (Nice thing about acrylics is it removes super easily if not fully cured.) and will try it again tomorrow. Hopefully it won't have the same effect.
Again, thank you to everyone for the help!!!
Funny you should mention that. I have 7 unbuilt ore jenny kits I plan to build as my next project. I have never experienced the paint problem in your photo. My painting schedule goes like this.
1. Degrease with paint thinner/charcoal lighter or alcohol on a rag. Only necessary if heavy grease contamination such as you get on locomotives. Usually the hot water and detergent is strong enough to cut oil and grease and finger prints.
2. Wash in hot water and dish wash detergent (Dawn works good and is widely available all over the country but other brands work too) Scrub with an old toothbrush. If you executed step 1, this will remove the solvent you used which is a good thing. Depending upon what solvent you used, it may do bad things to the paint
3. Rinse in hot water and plenty of it. Hold the model under the hot water tap for at least 60 seconds, more is better. You want a lot of water, flowing for a good long time to wash away the crud that the detergent loosened up. Just putting the model into a bowl filled with distilled water isn't going to do it.
4. Good long air dry. over night at least. Couple of days is not too long. Do not touch with bare hands from here on.
Actually, running the model thru a household dishwasher ought to handle steps 2 3 and 4. I have not tried that, lacking a dishwasher. You might want to run a junk car thru first just to make sure. And negotiage with the significant other for kitchen access rights.
5. I use rattle cans as much as possible these days. Ore jennies are either black or boxcar red. Krylon or Rustoleum dark gray auto primer makes a good black under layout lighting. The red auto primer makes a good box car red. The auto primers are sold to auto mechanics to paint over greasy little parts on serious rebuild jobs such as engine swaps. The primers have the best stick-to-metal chemistry that is known to the paint companies. Styrene is much easier for a paint to stick to as opposed to metal. I know the auto primers stick and cover better than any acrylic paint.
6. Spray out of doors or in a spray booth. You don't want that fresh paint smell to go all over the house. And you don't want overspray all over your shop. It gets sticky, fast. Hold the rattle can close enough that the paint goes wet. Stay back far enough to avoid sags and runs. 18 inches is usually right. Push the button to start the spray before to spray hits the model, and keep the button pressed until the spray is clean off the other end of the model. This way gives the ends of the model the same amount of paint as the middle of the model gets. Too thin a coat is easily fixed by sprayig a second coat. Too heavy a coat is unfixable, short of paint remover righ down to the plastic.
7. Let dry at least overnight and a couple of days is better, before decaling. There is a lot of lore to decals but this post is too long already so I won't get into the lore of the decal.
David Starr www.newsnorthwoods.blogspot.com
I saw something similar on a model kit I was building. I was painting semigloss black over Tamiya primer and got similar looking fisheyes. I talked with Aaron Skinner of Airbrushing with Aaron fame and he thought it might have been something in the plastic itself, as he'd seen that before.
I notice in your steps listed, primer wasn't one of them. It also looks as though the paint was pulling a bit from the edges. Either a light mist coat, or primer, would add some tooth to the surface to help the final coat stay where you want it.
I like the Tamiya spray can primer as it's easy to spray and is "hot" enough to grab the plastic. It's also very fine pigment, so it doesn't hide detail.
Good luck on your next go-round!
Eric
Eric, You are the winner... Not sure what your prize will be yet.
It did the same thing with the second attempt, so I tried a light dust coat, and it crackled. I then tried my airbrush surface primer, and it crackled...
So I dug out the remaining rattlecan primer I had left over from pre-airbrushing days, (ModelMaster) and that seems to be working much better.
So it must be something in the plastic itself dislikes my airbrush. (Or at least Acrylics... My airbrush primer is Vallejo Surface Primer, Acrylic version...)
Looks like I will be needing to order some Tamiya in the future if I continue with projects like these. (Now that ModelMaster is discontinued.) Wonder if HobbyLobby coupon will work on that?
Thanks again to everyone!!!!