The past few days for me have been spent fabricating the steel post members that will support the CropStop’s handrail, which we will be installing this upcoming weekend. Specifically, the last three days have been spent finishing these posts. When you start building something from raw steel, there are various steps you have to take to “finish” the surface of the metal to successfully protect it. You have to protect steel from the oxygen in the air and water so that it doesn’t rust away in few years.
First, after you are done welding and grinding, you have to remove oils and carbon from the surface that were put there when the metal was produced in the steel mill. You achieve this with a Tri-Sodium Phosphate Substitute (you shouldn’t use real phosphates, because they feed algae in the environment that can sap oxygen from our lakes and rivers, throwing off the ecosystem’s balance). Once the oils are removed you must coat the steel in a primer coat to achieve that initial layer of protection, and also to give an even base for your final coat to attach to.
We elected to use spray paint for this coating process, which comes with it’s own set of craftsmanship rules if you want to acquire a nice even coat, without splotchiness or dripping. You also can’t use it if the temperature is less than 50 degrees, which added an extra challenge with the Charleston weather this week. We had to find a big industrial heater to warm up the painting area. It was tough to get the hang of, but short, quick strokes about 5 inches away from the surface yield the desired result. We put two coats of primer on to make sure it was fully and consistently coated.
Last is the finish coat, where we decided to go with a flat black finish. Since we are putting two coats on, the bottom coat’s finish doesn’t matter and will be masked by the top coat, so luckily we had some extra black gloss from an earlier project to use. We’ll put on the final coat today, and the finished members will be on their way up to their new home in Greenville in no time!