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Paint still not dry

Posted: Sat Nov 26, 2016 16:07
by RPadavan2
I'm working on my Airwolf Bell 222 helicopters from Shapeways. I tried to apply the black paint for the top but the white was coming off on my fingers from the handling. I painted the white bottoms a couple days ago and it is still tacky. The primer coat was completely dry, and had been for a week or two before I started painting the white. The models have been sitting in my living room, at room temperature. The paint color is Testor's Insignia White. Any suggestions as to how I can get the paint to dry? Or should I strip it down and redo it?

Re: Paint still not dry

Posted: Sat Nov 26, 2016 19:45
by spejic
I think you have to strip it down - if it hasn't dried yet it isn't going to, at least not in a good way. Try using a lacquer-based primer (like Tamiya spray primers) or switch to acrylics to paint the colors.

Re: Paint still not dry

Posted: Sat Nov 26, 2016 21:03
by ajmm
Funny - I haven't had that with my Testors whites and actually I find them much more reliable than any other enamel or acrylic alternative. Very odd. As Spejic suggests, my own course would be to strip it down and try with something else. It's very irritating when that sort of thing happens.

Re: Paint still not dry

Posted: Sat Nov 26, 2016 22:36
by Jonathan
i have had this problem with Model Master spray enamels. even a week left in the hot car in the summer didnt cure it.
Cant be sure its the same stuff, but Model Master is a Testors product. It has a "low toxicity" solvent that wont kill brain cells as fast as the stuff in Tamiya, but also may never finish evaporating.
Tamiya sprays are great paint and dry hard as glass, but wow, ventilation is a must!

Re: Paint still not dry

Posted: Sun Nov 27, 2016 0:04
by RPadavan2
Thank you all for your suggestions. The primer was Tamiya spray primer. The Testor's paint is a Model Masters Enamal. The rotor props I painted the same day are dry, but the main body is not. Seems like the only problem I have is with the Insignia White or Classic White. I tried Classic White first, but it didn't cover well. I figured it was old and not mixing well so I stripped it and allowed a couple days to dry before I primed it again. And prior to the original priming, the model was washed with dish soap and water using a soft bristled toothbrush.

Re: Paint still not dry

Posted: Sun Nov 27, 2016 18:27
by spejic
That's really weird because it's rare that acrylics have this problem, especially after a primer separates the paint from the plastic. What are you using to thin the paint? How long did you wait after the primer to paint the main color?

EDIT: I misread your post. Enamels can have this problem over certain kinds of plastic. I would try stripping it, cleaning it thoroughly with alcohol, painting a couple coats of primer, and letting that dry a few days before trying to paint again. If that still doesn't work, you will need to switch to acrylics for the final paint.

Re: Paint still not dry

Posted: Sun Nov 27, 2016 18:45
by McYellowbelly
Could be whatever was used to clean the Shapeways.
When I worked with similar materials, we used solvent to clean them.
Sometimes they stayed 'sticky' and paint wouldn't adhere.
MAybe strip back and re-clean with a solvent?

Re: Paint still not dry

Posted: Wed Nov 30, 2016 7:33
by RPadavan2
I stripped down the tacky paint. Yes, five days after painting still tacky. Giving it 24 hours to dry before I re-prime it, possibly longer depending on how I feel after work on Wednesday. Then a day, or more, after priming to allow it to dry before I attempt to paint it again, this time using acrylic paints. I also have a product from Smooth-On called XTC-3D on the way. It is a two part sealer used to cover 3D prints and resin castings. It is advertised as filling in and smoothing out the striations found in 3D printings. It can be sanded and painted after drying. I got the smallest amount, 6 oz bottles, to give it a test run. Wish me luck.

Re: Paint still not dry

Posted: Wed Nov 30, 2016 15:14
by McYellowbelly
Only bought one Shapeways models, a C-3603 Schlepp.
Had it cleaned, using solvents, primed,painted,decalled.
Now 18months later, some of the paint has started to lift!
Be interested to see how you get on with your primer

Re: Paint still not dry

Posted: Thu Dec 01, 2016 1:13
by spejic
It beginning to sound like painting over 3D models is like painting over vinyl - enamel paints just won't work. I've put acrylic paint (what I normally paint with) straight onto both on the Ultra Detailed material and the normal white strong material and it works on both without problems 2 year later.