Hi all!

I just got done spraying my first base coat with an airbrush. It was fun! However, I have a couple questions and concerns about the results.

I've been working on a Pz IIIL and wanted to give it a nice dark base, so I sprayed on a coat of acrylic Tamiya Nato Black, thinned 1:1 (at the recommendation of the owner of my LHS) with Tamiya lacquer thinner. It seemed to be going on great, but after a day of dry time, it feels grainy and a little coarse to the touch. When I do lightly touch it to see if it has properly cured, a small amount will come off on my fingertip. Is this normal? I'm concerned that the paint hasn't properly adhered to the plastic.

One thing I must admit, I initially sprayed a coat of Tamiya German Grey from a rattle can on the model several months ago, when I wasn't as knowledgeable about the painting and weathering sequence (Thanks, Matt for setting me straight with the awesome stickied thread in this forum.)

Is there any reason the acrylic paint wouldn't have adhered to the (ill conceived) coat from the spray can? Does it just need more time to dry (I've read that leaving it for 2-3 days is normal)? What sort of options do I have in the event that it hasn't adhered properly - should I try sealing it with a coat of Dullcote, or can I simply paint the top coat over it to seal it in?

I know that's probably a lot of questions, but if anyone has any tips I would greatly appreciate it!

Cheers,
RE

Did you say you used Tamiya LAQUER thinner with ACRYLIC paint?


If so, that is your problem. I had the same issue when I first started modelling. I used Testors ENAMMEL thinner with their LAQUER clear coats. Had the fuzziest tanks for a while.

I believe Tamiya paints can be sprayed right from the jar. I know a lot about MM paints, but not Tamiya, so maybe somebody else has some insight?



Hey, are you going to strip the model and repaint?

Just curious.

Mark

To much air pressure will cause this probluem also. ACESES5

Sorry, I should have been more clear. Thinning Tamiya acrylics with Tamiya lacquer thinner (the yellow cap) is actually a known method, and a number of people have told me they get better results with that than Tamiya acrylic thinner. There are a few posts on it here, though I can't seem to bring up the links at this moment.

I'm not going to strip the model unless it absolutely necessary. I'd rather not have to go through that process, but if it isn't fixable, or will hinder future coats, then yes, I'll strip it.

Thanks for the tip about air pressure. I was fairly certain I was spraying at around 15 PSI. Is that too high? Should I be closer to 10?

Thanks!
RE

Hi Russ,
Okay it's Sunday afternoon, relax, have a beer. We'll get you fixed.
1. You are very welcome for the sticky thread. It's helped a lot of people. I ought to put it in a book and make some money!
2. Your LHS owner did not mis-direct you. Tamiya acrylic shoots best at 50/50 and it's not completely water based. For some reason the guys in Japan found out it works great with Tamiya Lacquer thinner. It also works great thinned with $1 a gallon blue windshield washer fluid.
3. What you describe is called "pebbling". The finish is grainy/rough/powdery. This is caused by the paint partially drying in the air between the nozzle and the model. You need the paint to go on wetter. Watch carefully as you airbrush - you want the paint to go on wet and shiny, and you want to keep a wet edge as you go. It should be smooth to the eye.
To cure pebbling, get the airbrush closer to the model so that the paint goes on wet. If you are still having problems or are experiencing airbrush clogging, go to a Michael's Crafts store and get a bottle of Liquitex Slo-Dri. Put a few drops in your airbrush paint mix. This is a retarder (don't worry it only effects the paint, not the painter!) and will make your paint dry slower.
4. You need to strip the paint and start over. If you want to strip only the acrylic layer, immerse the model in a tub of generic Windex overnight. It will dissolve the acrylic without the need to scrub and break off parts. If you want to remove the Tamiya German Grey spray paint (which is a lacquer) along with the Tamiya acrylic, immerse the model in a tub of DOT 3 brake fluid overnight. When all the paint is gone, rinse in cool water, let dry and start over.
Happens to everybody. No big deal.

Ive heard some great things about using the lacquer thinner. It is possible that your airbrush was too far away from your model. I usually spray about 4 inches away from the model. I too often get that finish you are describing when using tamiya paint, it is why im switching to Vallejo.

I shoot Tamiya acrylics at 5 - 15 PSI depending on how tight a pattern I'm doing. 15 is fine for an overall color. You're right in the ballpark Russ.

Matt, thanks for the all the great info. I have the feeling that I was probably too far away with my airbrush. As it was my first time painting an actual model (I've been practicing on newsprint to get the hang of airbrushing) I was really careful to make sure I was applying thin, even coats. It looks like I was trying to be a little too careful.

I did get a wet, shiny appearance on a couple of occasions, but I backed off with the airbrush to make sure I wasn't applying the paint too heavily.

I'm a bit bummed about having to strip the model (that NATO Black looks great over a whole tank), but I'm really glad you pointed out the DOT3 brake fluid option. I've been kicking myself about that coat of German Grey ever since I put it on. I'll take the loss of the Black if it means I can erase an earlier mistake.

I'm going to try shooting a little lower, say 10ish PSI, and see if I get better results. Like the airbrushing I'm finding I have a lot to learn about the finer skills of using a compressor. But I'm enjoying it. I'm going to have to pick up some more NATO Black, as it almost a full bottle to cover that tank.

Thanks again for all the help!

Cheers,
Russ

No sweat Russ, you're welcome.

Hi Russ,

May I suggest using a little more thinner? Tamiya acrylics actually have quite a dense pigment load and your 1:1 mix may be a bit heavy at the 15PSI that you're using. If you're using Tamiya lacquer thinner, it shouldn't be a problem to take it up to 2 or more parts thinner to one part paint. This will also reduce (but may not eliminate) the "tip dry" problems you are experiencing.

2 parts thinner to one part paint, 15PSI and a distance to subject of about 4-6 inches should be within the "sweet spot". You need to work on your paint flow so that, as mentioned, it goes on wet, but not so wet that it runs.

If you used a whole (10ml?) jar of paint for one model, I would say that you're using way too much and coupled with the pebbling that you're experiencing, it's suggesting to me that you're painting from way too great a distance.

Good luck..

Greetings,

Everyone here has given you good advice but I just want to add one more thing. Don't check your spray pattern on a piece of paper. Paper is absorbent and not at all like the surface of the model you will be painting. Someone told me a long time ago to use a surface similar that that which you will be be painting. As a result, I use something from the spares box and a piece of coroplast in my spray booth. Coroplast is like plastic covered cardboard and is used in sign making and political campaign signs. It is just like the surface of a model so when you do a test shoot, you can see exactly what the spray pattern is doing. I always shoot a test blast at the old model or piece of coro before my airbrush tip goes to my model. Coroplastic is pretty cheap and when it gets covered in paint cleaning it with windex (acrylics) or laquer thinner (enamels) will make it good as new.

Hope this helps you,

Cbreeze

I'd just like to say you can pickup the Corplastic or sign material at places like Home Depot. I actually picked up some for use with scratch building. It's cheap and you an get a lot of it for very little money. I never thought of using it for testing the airbrush prior to spraying. I always just shot it on a piece of paper or cardboard. Excellent tip!!

Actually I get mine on street corners at election time. After the election of course :-)

Cbreeze

LOL!

Sorry for the misdirection with the Tamiya Laquer thinner.

I didn't know it works with their acrylics (as a side not if you ever do use Model Master, do not mix different bases and thinners).


If you still have a rough surface on the current model you are working on, I have found 2 things to work

1) very carefully sand the noticable areas with 2000 grit sand paper. It should take the edge off. This method is a little difficult to get uniform results or without damaging PE. It also uses a lot of 2000 grit paper, as it loses its grit after a few cm^2 of rubbing.

2) I do the "oil dot" method of filters. I find that this technique almost fills in the lows and makes the model quite smooth. I don't know if you do filters or have done the oil dot method before, but food for thought.


Again, sorry about the misdirection on the Tamiya paints.

Thanks for the continued replies - all this information is very helpful, and will help me make sure this phenomenon doesn't happen again. (Learning experiences - 1, Russ - 0).

Thanks Phil for the suggestions on thinning/airbrush distance. I'll give the 2:1 thinner to paint ratio a try. Like you said, the pigment in the acrylic is pretty dense and should hold up at that ratio. I also thought it was a little strange that I went through an entire 10ml bottle for a single base coat. Granted, this was my first time painting so I didn't know what to expect, but I still thought a bottle would last longer than that. Adding to the problem was the fact that the model already had a coat of German Grey on it, so seeing which areas had good coverage with the NATO black was hard to determine. As such, I probably oversprayed a number of areas. I'm taking off the layer of grey as we speak, which should hopefully solve that issue.

Matt - I've had the model in a tub of DOT3 brake fluid for about 24 hours, and while the pebbled coat of acrylic is gone, the lacquer-based German Grey is still adhering to the model. It comes of with some scrubbing, but should I leave it in the fluid awhile longer to see if it will remove the coat further, or am I going to have to scrub it off manually?

Cbreeze - thanks for the tip on the corolast. I'll pick some up for future use - as you said, its better to spray on things that closely resemble the final material.

JC - thanks for the info on another way to dilute/thin Tamiya acrylics. Hopefully my problem can be corrected by simply getting closer to the model, as you said, but if not I'll try out that formula you have.

Thanks again all!

Cheers,
Russ

Russ,
The brake fluid should have dissolved the German Grey paint. Tamiya lacquer sprays are weird stuff. If it doesn't all come off with the brake fluid, then you need to go caustic. The last and least desirable option is Easy-Off oven cleaner. This stuff is very nasty. Get a mask, some gloves, and a big food storage bag that the model will fit in. Put the model in the bag and saturate it with the oven cleaner. Seal the bag, leave it overnight, and flush it with water the next day.

If there is STILL paint left on the model, the tank is clearly possessed by dark forces. Place the tank in your garage and move to another town immediately!

Matt,

Thanks for the advice! I'll have an exorcist on hand for the next round, just in case the paint doesn't come off with the caustic stuff. That or the car running in the driveway!

Cheers,
Russ

Greeings,

Just wanted to add something here. I am presently on a Tamiya HUMVEE build. I am using MM acrylic just because I had some laying around. I am switching to Vallejo. Anyway, I have never gotten consistent reslults with MM. Some days good, some days bad.

I painted a piece of the model last night and got a rough finish. I immediately thought of this thread. So I am trying to figure out what to do short of stripping and re painting. I grabbed a q tip and rubbed the surface of the model which polished the finish a bit. Thinking this is good, I dipped the q tip in a little bit of windex,, I also tried good old fashined saliva too. I rubbed some more and wound up getting around all the roughness out. I made sure that the surface was clean and shot another light coat over the surface and got a perfect finish. You have to be careful and not use a q tip drenched in windex, just slightly moist or you might start removing the finish. Anyway, I thought I would pass this on in case your have any further problems. I never, ever had good consistent results with MM. Vallejo is the way.

Cbreeze

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