This technique is covered extensively on our Doctor Ben's How-To #2 "ABCs of Staining Castings" which also includes staining wood metal, resin and brick surfaces. The image at right is the completed Scale Model Masterpieces/Thomas Yorke "Practice Wall" kit illustrated in the Doctor Ben's How-To #2 booklet. The specific technique used addresses how we created the stained stone finish of the recently released "the Short Line Freight Shed & Boiler" kit (O Scale #9162 & #3162 HO Scale-Scale Model Masterpieces/Thomas A Yorke Ent.). Doctor Ben's Weathering Stains and Instant Age Weathering Solution were applied with a standard 1/4" round soft bristle brush commonly used for applying watercolors.
These instructions recommend the Doctor Ben’s line of Weathering Stains, Solutions, and Industrial Pigments for sealing and finishing the gypsum castings. These steps are also applicable to resin and metal castings after the aforementioned steps are taken.
After the castings have had any unwanted flash removed from around the edges and openings, they are ready to be sealed.
Step #1 — Using a 1/4" round standard watercolor brush, apply a "thinned" wash of Doctor Ben’s Depot Buff Weathering Stain (#1068) in a random, splotchy pattern. The "thinned" stain is created by dipping just the tip of the brush into the Doctor Ben's Weathering Stain (shaken well before opening) and then quickly dunking the brush into an open container of Isopropyl Alcohol (70%) and then dabbing tone small area at a time. Wait a few minutes before moving onto Step #2. Be sure to coat the backs and the rough edges of castings, because rough surfaces tend to be more porous than smooth, molded surfaces.
Step #2 — This time using the same technique as in Step #1, apply Doctor Ben’s Black Mahogany Weathering Stain (#1086) to the stone surfaces, after the "thinned" Doctor Ben’s Black Mahogany is applied, use a paper towel to dab off the Doctor Ben’s Black Mahogany off of the tops of the stone faces. Once again, wait a few minutes before moving on to Step #3. Note the blotchy randomness of the Step #2 casting in the above images. This Step may have you second guessing whether or not that you are doing this correctly. But, note the look of the Step #3 casting. This is what Step #2 looks like "after" the Step #2 application has had some time to dry.
Step #3 — After Step #2 has had a few minutes to dry, us the 1/4" round brush to "dry-brush" Doctor Ben’s Antique White Weathering Stain (#1094) to just the tops stone surfaces. When dry-brushing the Doctor Ben's Antique White on the the casting, not every stone will receive the weathering stain. The purpose of dry-brushing the Antique White is to highlight the stones that protrude out the farthest leaving the non-protruding stones dark creating the illusion of depth. In the event that too much Antique White is applied to a stone or area, simply clean the brush in the Isopropyl Alcohol and wash the Antique White off with the Isopropyl Alcohol still on the brush and dab with a paper towel if needed.
Step #4 — Doctor Ben’s Worn Concrete Weathering Stain (#1095) will be used to stain the window lintels as well as where the masonry window will rest inside the opening. Finally, using the same technique as in Step #1, apply a very, very thinned wash of Doctor Ben’s Instant Age Weathering Stain (#1152) to the the entire casting. If needed, use a paper towel to dab off the Doctor Ben’s Instant Age off of the tops of the stone faces. This final step will unify all the steps to a more fluid, unified look. Allow the stained castings to set overnight, even though they may seem dry after just a few minutes. The difference of drying over night to allow the Isopropyl Alcohol to completely evaporate will result in more natural look that just after all four steps are completed.
The techniques described here are only guidelines to help you to create the look you want. The important thing is to do it the way you will like it. The methods outlined here will take a little practice. Just jump in and try and don’t be afraid to make a mistake or two. Mistakes are only opportunities. You’d be surprised how many “mistakes” actually work.
FYI Pilot Model construction by Richard E. (Ben) Bendever and weathered using Doctor Ben's Weathering Stains, Solutions & Pigments as described in the kit instructions.