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Help, Uncontrollable nitro runs


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I'm finishing my first body using Stew mac Colortone nitrocellolose lacquer.  I put on Stew mac nitro sanding sealer with few problems. A couple runs, but it was obvious I was being heavy handed. Now I'm trying a color coat, tinted with Colortone stain, un-thinned. I started with a very light coat, no problem. The later coats run along the edge, specifically near the horns. I'm spraying with Preval, and hanging to dry after I spray. The last coat seemed to dissolve the earlier coats and ran. After the last attempt, I just wipedit, and all the color came right off. I knew the latter coats could dissolve previous coats somewhat, but enough to cause a run?


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Sounds like spraying too heavy still. I think more of it is coming from being unthinned. Your are laying down a lot more solids which is the heavy part, causing the runs. I would try thinning 50%. Especially with the color coats you are looking for something to carry and bind the color, not necessary build thickness. 

Also watch your distance to the work surface, lighter coats up close don’t disperse as much and will lay down heavier. Remember your 50% overlap patterns, even with the Preval.

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Thanks for the help.

I guess I was thinking that un-thinned would run less, but I didn't think about the solids.  I'll try thinning and going easier on it.  The color is building up much more slowly than I expected.  I'm using the 1/2 oz. per quart ratio recommended in the Colortone instructions.  Is there any reason I can't go heavier on the stain to lacquer ratio?


If I wiped off the color and exposed the wood, is the sealer coat gone as well?  No big deal if it is, this is a cheap practice body but it would be nice to know for future endeavors and errors.

Thanks again

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I would venture a guess that the dealer should still be there. 

There is a nice thread or tutorial about painted taped off patterns, the main point was heavily thinning and getting color with minimal build. I think you want the color ratio to be based against the thinned volume of lacquer, not pre-thinned. That will increase the ratio of color to lacquer. At worst I would try some different mixes on scrap.

practice is the best tool. When I switched to poly it was learning all over again and then going to an HVLP gun I had to change me entire technique.

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