Kris,
Thanks for your authoritative and practical treatise on Tru Color and painting in general. I sprayed test panels painted with CB&Q Freight Car Red with Poly Scale Flat Finish, Poly Scale Satin Finish, Micro Flat, Micro Satin, and Dullcote. The results under 5,000 K light are as follows:
The colors are listed in the order of best color fidelity to the original:
Micro Satin
Micro Flat
Poly Scale Flat Finish
Dullcote
Poly Scale Satin
Whitening is noticeable with both Poly Scale finishes, but not so much with Micro Satin and Micro Flat. Dullcote gives a slight browning effect, probably due to the yellow component in the carrier. I’ll get some Tru Color clear finish and give it a try.
I have an Iwata Power Jet Pro dual compressor with regulators built in. I suspect the regulator calibration may be a bit low, so I’m probably spraying around 33-38 psi instead of 40. I’ve noticed my pressure setting is higher for Floquil and thinned Poly Scale than published recommendations.
I’ll try some rattle cans of Tamiya primer.
Thanks again,
Nelson Moyer
From: CBQ@yahoogroups.com [mailto:CBQ@yahoogroups.com]
Sent: Thursday, February 26, 2015 4:26 AM
To: CBQ@yahoogroups.com
Subject: RE: [CBQ] Tru Color CB&Q Freight Car Red
Nelson please see my responses below in red.
I asked the questions was that I sprayed some CB&Q Freight Car red undiluted on some stock car interiors using a Paasche H series with a #5 tip, and it took 40 psi to get the paint to flow.
With Tru-color I like to use the larger tip and yes I do open it up almost as far as possible. Undiluted I notice my best results in spraying around 30-35 psi. I just sprayed 18 GP9's this past week in tru-color and they were all straight from the bottle at 33 psi.
The spray pattern wasn’t as feathered as I get with some other paints, and there was some stippling at the edges. I had to screw the tip out almost all the way to get paint to flow at all.
I haven't paid much attention to the spray pattern but I'm thinking for me at least it's fairly close to other paints that are water based. I'm thinking I get a larger patter with a solvent based paint. The painting I described above was with no stippling. We have a regulator allowing very precise control and I have found that just a little bit over can produce the results you have related. So that may be a suggestion is add a good regulator that gives you precise air control.
Those results suggest that a little thinning would be beneficial, maybe 4 or 5 parts paint and one part thinner. Tru Color cautions against using acetone as a thinner because it may affect the gloss finish. I don’t know if that true, or they just want to sell thinner.
Let me say this in my experience I've used Acetone without issues, that's not to say that others haven't but I have not noticed it. The only paint that I find that truly does a 100% gloss finish is Scalecoat. With that said I decal right on top of Tru-color without issue. Now with our experience we have found that the best result to make a decal disappear even on a gloss surface is to gloss coat the area of the decals after they set up and before coating with a final clear coat.
When we have diluted Tru-color (My brother prefers to dilute his) or rescued a dried up bottle we use a 75% paint 25% thinner / acetone, and spraying at 20-25 psi. I'm sorry to say even this various some by eye sight ie: it just looks right and of course this is confirmed by trial and error. We purchase a bunch of junk freight cars for a buck at train shows and use those as our spray test panels when painting to make sure we have the right mix/pressure before painting a model. Rather ruin a $1.00 freight car than a model we've invested time and effort into.
The place where we tend to make sure and use the mfg's suggested thinner is when mixing / thinning clear coats.
The other problematic issue for me was that I sprayed resin without priming, and my builders marks showed through the paint. Apparently, Tru Color is more translucent than acrylic paints I’ve use, and based upon that experience, I think I’m going to have to prime models before using Tru Color paints. Maybe other colors cover better?
I should have mentioned that in my original post, since the Tru-color is more like a ink than paint it's much more translucent. Even with primer it can sometimes take 4-5 coats, but since Tru-color is so thin and dries so fast that it's not really a problem unless your really impatient.
We prime everything! Tamyia primer almost exclusively it's expensive but well worth the cost in my opinion. We purchase it in spray cans, you can purchase bottles and mix it yourself but we've found the can is easy and goes a long way. When we figured it out it cost us less over time to use the cans over mixing it ourselves. We use white under any of the more translucent colors (Red, Yellow, Orange, etc) and we use gray under all other colors.
I have a gravity feed Iwata Eclipse, but I haven’t tried it yet with Tru Color paints, pending some feedback to my original questions. Another issue is the marked color change that occurs after spraying gloss models with Dullcote or Poly Scale Flat Finish. There are slight shade differences between the two flat finishes. I have some Poly Scale Satin and some Micro Flat and Micro Satin, but I haven’t sprayed a test chip to see how they affect the color and shade. The flats I’ve tried suggest that you can use different flats and satins to simulate various degrees of fading, but my tests are much too preliminary to confirm that suspicion.
I find that with Tru-color there is not as much a color shift if any when using their clear coats, as there is with enamel paints after clear coating.
In my experience you will notice a difference between the same color coated with Testors Dullcoat and Polly Scale Flat Finish, just based on chemical make up. Dullcoat is enamel based and has a slight yellow tinge to it where as the Polly Scale (Now Testors Modelmaster Acryl line) is Acrylic/Water based and has a slight white tinge to it. Tru-colors clear coats seem to be 100% translucent.
The best test to show this is take Testors Gloss Coat and coat anything white, within a 6 months to a year you will begin to notice a yellowing from the clear coat. You should also see the yellow when mixing it up. I have some police car models and Nascar models I built in the early 1990's that show this all to well. But back then the only non-enamel clear coat was the stuff used by Dupont on their Nascar.
If I missed something or did not clearly explain anything please let me know.
Kris
