I have now ruined four Shapeways shells.

[AKNscale]

We mainly use SC-I in our group and I haven't seen or run into those problems, what kind of airbrush are you using? I know that if you thin it too much it can cause havoc also. Filling details in sounds like it's way too thin, but I could be incorrect. I've also never used the primer. I've just cleaned the shells with warm, soapy water and then shot them. This was taught to me by guys who have been doing it for years.

As for True Color, my buddy Pete tried it and had tons of issues with it(plus, the ARR colors look wrong). Maybe it's a technique issue because he's used to Scalecoat.

[atsf3751]

Your first pic is very nice. I do not try to airbrush narrow areas like the walkways, I will paint by hand with a brush. I find that gives a much better result with a lot less effort.

[C855B]

We mainly use SC-I in our group and I haven't seen or run into those problems, what kind of airbrush are you using? I know that if you thin it too much it can cause havoc also. Filling details in sounds like it's way too thin, but I could be incorrect. I've also never used the primer. I've just cleaned the shells with warm, soapy water and then shot them. This was taught to me by guys who have been doing it for years.

As for True Color, my buddy Pete tried it and had tons of issues with it(plus, the ARR colors look wrong). Maybe it's a technique issue because he's used to Scalecoat.

Airbrush? Harder-Steenbeck Colani w/ 0.6mm nozzle. As to the primer, Tamiya Fine Filler. I've found it an excellent solution for dealing with Shapeway FUD/FXD surface irregularities. I think the results in the first photo are indicative of what's possible.

"Too thin"? My rule-of-thumb reducing SC paints has been 30% thinner, although that was with other airbrushes. I tried it less thin in testing, and was still dealing with thickness issues as indicated by ridges around the masking. Clearly, it doesn't like me. How much reduction are you guys using? Are you finding any handling differences between SC-I and SC-II? I've only used SC-I until this project, and apparently I need to consider my assumptions about similar characteristics.

Your first pic is very nice. I do not try to airbrush narrow areas like the walkways, I will paint by hand with a brush. I find that gives a much better result with a lot less effort.

Oh, I agree. You can see how that backfired with the lacquer.

[coosvalley]

In situations where I need to brush paint over Tru color, I use cheap acrylics, the kind that are roughly a dollar(US) at Wallymarts....

The painted decals are a good idea too, and I have used that approach before too, with pretty good results..

 

[robert3985]

I know this may read like a dumb question, but...if you're using SC-I, what thinner are you using?

SC-I and SC-II are not the same paint, and SC-II uses plain paint thinner, whereas SC-I uses something akin to the original Floquil thinner, and it etches/dissolves plastic.

If you are using plain paint thinner with SC-I, that is probably the source of your airbrushing problems.

If not, I'd invest in a Badger battery paint mixer and mix up your thinned "airbrush-ready" paint in a separate bottle...mixing with the Badger mixer before use...don't shake it.

In my experience with both SC-I and SC-II, they are excellent paints, covering well and thinly with a wonderful glossy surface to apply decals to, and their color is exact as to early 80's U.P. paint colors, as opposed to all other paints (I haven't color matched True Color paint yet).  The Harbor Mist Gray is especially exact for new U.P. paint.

I use Paasche airbrushes...VL-1's VL-2's and VL-3's...and the ubiquitous turbine-driven Paasche AB, and I've never had a problem with Scalecoat paints, which I consider to be the best model railroad paint available for U.P.

Cheerio!
Bob Gilmore

[C855B]

SC-I gets the official SC-I thinner, SC-II gets SC-II thinner. I'm aware of the volatiles differences between the two. They both clean up with straight xylene, but I don't use that to reduce even though xylene is the primary SC solvent in both formulations

So... based on the comments here I obviously need to do more testing with the reduction mix. The airbrush is not the issue, it is a high-end gravity feed double-action artist's brush, just one we normally don't see in MRR circles - roughly equivalent to a Grex Genesis. I get great results with Tru-Color straight out of the bottle, so evidently I need to tune the reduction regimen with Scalecoat, and maybe... just maybe... consider a different nozzle size. I have a 0.4mm nozzle (using a 0.6mm now), but my edu-guess is I would need to go larger to reduce the air in the mix, which may well be the source of the original issues with it going on too dry when I tried to keep it thin. OTOH, a Paasche VL #1 needle is 0.56mm, so figure that one out. I have a VL last used about six years ago, learning in the interim I prefer a gravity-fed brush.

I'd be curious about what you think of Tru-Color, both handling and color matching. What I can tell, color is very close to SC, but possibly not quite as transparent as SC. I apply the yellow over white anyway.

[AKNscale]

We've been doing the same as you, 2/3 paint, 1/3 thinner(SC-I thinner). Then mix it and check the thickness with the stir stick. That's how the others have been doing it like that for a long time before I came around. The brush I use is a Badger 360.

I've never worked with SC-II. I'm on board with if SC-I works, I've no reason to change to SC-II. Jerry shot some of the SC-I primer and it seemed to do well. I believe Jerry used to use citadel primer and liked it quite a bit. I'll have to verify that.

Side note, there were 2 different yellows used by UP in the 80's.

[Ed Kapuscinski]

Find some old Polly Scale and brush it.

It's never failed for me.

[wazzou]

Find some old Polly Scale and brush it.

It's never failed for me.

 
I wish I'd have mentioned that  ^^^^   

[Ed Kapuscinski]

I'm not kidding though. I mean, I understand the advantages of spraying stuff, but in this case, it just seems to be causing much pain.

[amato1969]

Yes, that or Vallejo; water-based acrylic goodness.

  Frank

[Missaberoad]

I'm not kidding though. I mean, I understand the advantages of spraying stuff, but in this case, it just seems to be causing much pain.

Neither was Bryan   

Couldn't you touch up over the Tru-Color using something like Polly Scale Acrylic with a brush?  I know it's know longer made but is still around. 
I find it brushes as well as anything I've used.

[C855B]

A lot of testing has yielded positive results. I finally found what appears to be the right mix for Scalecoat II with my funky airbrush: 1 part thinner to 3 parts paint, 0.2mm nozzle, and 30psi. Yellow covers white in two nicely-thin coats, Harbor Mist Gray covers in one. I like the way it sprays now and I have a reasonable cleanup process for it, but it's not as easy to thoroughly clean the brush as Tru-Color is.

The paint decal idea for the walkways does not seem to work on this project. My concerns about the simulated tread pattern interfering with adhesion was right, the decal doesn't want to stick. I might try again with another paint, but if that fails I will return to careful masking and brush touch-up for the errors and small bits.

New shells haven't shipped yet and I am out of Bestine, so it may be a few days before resuming this particular adventure.