1. Always be aware of potential interactions between different materials you're working with.
This is grinder abrasive and steel dust. This is a drop in the bucket compared to what has been generated, just over the course of the floorboard adventure. In this dust, we have rust (iron oxide), raw steel (iron and carbon, maybe some extra spices), grinder wheel mystery meat, and flap wheel abrasive (aluminum oxide, zirconia, etc). Think of how well this would get along with a roughly equal measure of dust from grinding aluminum, and how excited the whole party might be when a good and hot shower of slag and/or white hot metal chips show up to join them.
2. Cheap welding blankets shed fiberglass more than a cat sheds fur. Same for how much material either spray out when hit with a grinder. A good static charge, a blower, or a heavy misting of water in the air, to be followed with a thorough vacuuming, are good things to help with this.
Alright. Back on the floor!
The point that determined how this should be handled is that it was unscheduled work. This wasn't on the list as a restoration task- it's a repair. This means that concessions had to be made in the name of expediency, with the first being that only sections of the floor got new paint, while the old shit stayed on parts that weren't being fixed.
The spot-treat approach adds a little bit of a challenge to the potential longevity of this kind of repair, since painting the rust preventative over the old paint would creates an overlap of the new paint over the old. This would create a substantial area for moisture and corrosive elements to be introduced to the unprotected metal. With this in mind, I've removed enough paint and undercoating to allow a space between where the new coating ends and the old starts. A shot of primer and paint over the bare space between coatings will still leave a small area that's not as well protected, but it won't introduce the same level of chance for the rust preventative to act as a barrier that will keep moisture in. I expect that it'll do the job until I feel like fully attacking the floor pan.
Here's the roughed out floors, still waiting for a final wire wheel pass to get the remnants of the tar undercoating off. I'm changing tenses from this point because I'm a liar and haven't actually finished this work yet.
Since the wire wheel will score the surface and carry tar into the metal, this will be followed by cleaning up with acetone. This will help make sure there's not any material left in the metal that will keep the rust preventative from adhering.
The rust preventative needs either existing rust or tooth to the metal for it to grab on and shrink around as it cures. Since this is mostly new metal, I could either treat it with an acid etchant, or I could rub it down with fresh abrasive. While the etchant will do a lot of good to increase the rust resistance of the metal, it takes more time than I have to spare. Time being a deciding factor, the metal's going to get a pass from the orbital sander with a fresh pad, followed by a final (second) scrub with acetone. This should have us all set and ready for part two: painting and patching. Or patching and painting. Patchainting.
No comments:
Post a Comment