Hi guys

Just had my first go at CM. Unfortunately the experience was plagued by gritty paint finsh. (Like sandpaper). I had to rub it back after each coat

I was spraying tamiya acrylic 50/50 with acrylic thinner (then later with lacquer thinner to try and sort it out). I even had a few drops of retarder in there for good measure.

Any ideas what was going wrong? Even lacquer thinner gave a gritty finish

Thanks for you help

Seems like your paint dried in mid air, how far was the airbrush from the model? Happened to me when the distance was too big.



Kind regards, Sven.

I spray Tamiya acryl mixed with Tamiya acryl thinner 1:1. For my 3mm tip, I hold the brush a couple of inches away from the model. For the .15mm tip, I hold it about 1/2in from the model. I spray around 30psi.

Hello Andy,

I second Sven`s statement. Happens normaly if the airgun is too far away from the model and the color dries in mid-air. So try to get some closer to the model.

Best Regards

Dennis

About 6 inches (15 cm). I was trying for a paint gradient, so I didn't want to get too close. I thought that might be an issue, hence the retarder. I'm thinking you could be right though, I was at 20psi to get good atomisation, but I had a relatively low flow rate

The effect is called "orange peel" and is caused just by what Sven said: the atomized paint droplets are drying (or partially drying) in mid-air.

Try reducing your air pressure and move the AB closer to the model. Warm and dry ambient conditions in your painting area can also make the problem worse or even create it. The warm dry air will cause the sprayed paint to dry faster than you might be used to.

Also be aware that corners and pockets and other places where moving air can get trapped or swirl around can allow over-spray to create the same effect on areas that you're not actually spraying towards.

Because paint spraying is a balancing act between many variables, sometimes even a single slight change in your painting conditions can cause problems when everything else is the same.

HTH,

Thanks for your help guys. Another newbie mistake. At least I only make them once

Andy;

As others have said - your paint is drying before it hits the plastic.

Retarder helps. I would also consider NOT using lacquer thinner - acetone-based stuff - as it evaporates very quickly and can really increase this problem. To some extent, the Tamiya thinner also engenders this too-fast drying.

I have found that using a mixture of rubbing alcohol (isopropyl alky - which evaps a bit slower than does ethanol and much slower than does methanol - something rather dangerous to use) and distilled or purified water works well for thinning Tamiya paints. Perhaps even better, and also slower evap, is car window-washer fluid (the cheap blue fake "windex" stuff). This stuff is also user friendly and pretty non-toxic and does not create a lot of solvent vapors.

Cooler temps, more humidity in the air, slower evap thinners, and a little closer to the build with slightly lower pressure should all help things out!

Bob

Well Most have already mentioned the distance between the model and your Airbrush being too big.

That said I have another little tip that will help you big time in getting a smooth finish. Mix a few drops of Tamiya X22 clear gloss into the mix. This will make the paint dry very smooth plus it has the additional bonus that it makes the paint have a slight satin sheen which is exactly what painted metal looks like.

Thanks guys

I've removed as much of the grit as I dare. I'll try to correct the CM with oils. Then after that's dried a couple of days I intend to give it a toot of clear mixed with clear yellow. Hopefully that should correct what orange peel remains as well as correct the hue which is too brown/tan at the moment.

As always - thanks for the tips. I'll make sure I use them next time.