Now that the 1946 Chris-Craft mahogany U22 is flipped, we are launching into the True 5200 Bottom fabrication process.
Actually, deconstruction of the outer and inner bottom planking begins the process. Given all the evidence found in the bilge that she has endured major oil leaks from the engine and transmission, step one involves breaking out the Silent Remover infrared stripping tool.
We use it sparingly, largely because its bulk makes using on a vertical surface exhausting, but primarily because it delivers even more than the hype you will find on the Web site. Aggressive hardly describes is capability to virtually pull paint or varnish from the wood. That aggressiveness, combined with gauging when it is time to lift and scrape, also makes it a dangerous stripping methodology for plywood strakes and surfaces that will be finished bright. Leave it on a few seconds too long and that smoke you see is wood burning, which leaves a charcoal-like surface behind it.
In this application, however, and especially when testing bottom planking for its paint adhesion retention, the Silent Remover’s aggressiveness is your friend. As you see in the clip, it literally sucks the oil out of the wood, leaving bubbling pools. The paint, and there were at least four layers here, just rolls off the surface, glistening with oil.
The other lesson of this clip is, “Take shortcuts at your peril.” Sure, fill the space left at a bottom planking butt joint with a thin sliver of mahogany rip. Why not? No one will see it behind all the paint. Hmmm…. except if and when the bottom is stripped the next time. Agreed. FAS grade, quarter-sawn mahogany is expensive, but that plank he/she cut too short could find a home elsewhere on the bottom. Why comprise the bottom’s integrity by taking shortcuts, especially almost directly beneath the engine.
We are preservationists who try to save every bit of old wood we can, but the integrity of oil-sodden wood is compromised, and it will not hold paint. We will be replacing virtually all of the planks, including the garboards from a bit ahead of the engine to the transom.