Modeling Information
Some railroad modeling materials require more than a liquid cleaning during the preparation process to ensure proper paint adhesion. This includes basic metal parts, delrin plastic (often used in handrails and truck sideframes), or any plastic part that has a shiny finish.
The accepted cleaning process is blasting them with an abrasive medium. Blasting is used to remove existing oils, paint and lettering, and create a dull/satin finish that allows the paint to “bite” into
the surface better. Aluminum oxide or sand is often used for metal surfaces. Baking soda is often used for plastics.
The modeling tool for applying the media of choise is an air eraser;
basically a miniature spray gun the size of an airbrush. I got a Model G78 Master Airbrush from Amazon
The cleaning process is a very messy job if the basting
media is not somehow contained. When I was volunteering at the North Carolina Transportation History Museum (Spencer Shops) we did locomotive and rolling stock blasting outside. We wore special personal protective equipment (PPE), heavy cloth suits with hoods, and ran air lines into the hood for safety. Smaller operations use blasting rooms or boxes to contain the medium, with appropriate PPE.
The WWSL
Knowing how the big guys do it, I am 'freelance prototyping' the process too. My PPE is a Gerson P95 Maintenance-Free Dual Cartridge Respirator (from Harbor Freight), a pair of goggles and rubber gloves. I have aluminum oxide (240 and 600 grit) and sand (for metal) and Arm and Hammer baking soda for plastic. Most of my abrasive blasting is done with the baking soda.
I abrasive blast outside. I use my outside air compressor set at its maximum. Depending on the project, I either hold the item with my hand or clamp it with a locking hemostat. 90 psi can blast a small part into space if its not locked down. A steady all around blast will do the trick in no time.
After blasting, I wash the item with water and/or isopropyl alcohol as appropriate.
If you are interested in building a booth see Rick De Candido's Fillmore Avenue Roundhouse Sand Blasting Booth.
Reference
airbrushresourcecenter.com
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