Laurel Mountain, like many rust blue formulas, contains copper sulfate. One function of it is some light immediate bluish staining that helps you to see that you have applied an even coat without missing any spots. It will sometimes "plate out" a very thin wash of copper if you apply too much to the surface of the steel, or work it back and forth. You only need to apply very thin even coating with a lightly dampened applicator to get decent rusting. In fact, Laurel Mountain is somewhat agressive, and you may wish to dilute it with distilled or rain water so that it doesn't bite so much, especially in more warm and humid conditions. It may take more passes to get the depth of color you want, but the rust will have a finer grain, and you won't get so much of a matte finish. With a more aggressive rusting solution, you also will want to be careful to not let the rusting go on too long befor boiling and carding.
I don't know how much your solution has plated out, and if it will result in an uneven rusting if you continue. At this point, it may be easier to just polish it off and start over. Or you could continue on with a smaller part, and see how it goes.
