Our splendid 100-year-old house was badly in need of paint, but apparently had never been scraped down to its original varnish stain finish, making an already distasteful task a nearly impossible one! Worse yet, the small removable blades in the paint scrapers I bought for the job were rendered useless after ten minutes' work. Even by replacing them regularly, the best scraping pace I could muster was only two or three square feet per hour.
So rather than waste my time using ineffective tools, I decided to invest it by designing my own heavy-duty paint scraper to suit the circumstances. I knew that my homemade paint scrapers would have to be nail-tough to stand up to the abuse I was sure to put them through. At the same time, they'd have to be capable of taking repeated sharpenings (so that I could spruce them up between bouts).
The best—and least expensive—raw material I could think of was the carbon steel used in automobile leaf springs. Accordingly, I went on a short foray through the local scrap yard, which rewarded me with a 2 1/4" × 28" spring steel arc that looked just about perfect for the tools I had in mind.
Since I had to deal with both flat, exposed surfaces (such as trim and windowsills) and hard-to-get-at joint areas (the lower edges and upper faces of my lapstrake weatherboard), I needed to make two different kinds of paint scrapers. Using my gas torch, I first cut the salvaged leaf into two 2 1/4" × 14" pieces, then shaped handles in those sections by narrowing their sides and rounding their butts, as shown in the diagram.
Once I'd accomplished this, I tackled the business end of each of these paint stripping tools. I wanted the first paint scraper to be fairly conventional, so I just heated its square end about 1 1/4 inch from the tip and bent the metal to form a 1" lip that was about 90° to the inside of the leaf's natural arc. It was a simple matter to grind a 60° bevel into the face of this lip, and sharpen the rear face slightly to establish a fine cutting edge.
After I'd formed and sharpened the blade, I heated it to a cherry red color and quenched it in water to harden the steel. Then, to temper the material—i.e., remove its brittleness while still retaining its hardness—I reheated the tool in the kitchen oven at 300 to 400°F. When the new implement assumed a light to medium straw color, I took it from the cooker and let it cool in the air.
The second scraper was meant for getting at my house's nooks and crannies, so I made it a bit differently. First, I cut two parallel lengthwise slots—1/16" wide and 3/4 inch apart—about 1 1/4 inches into the square end. Then I heated the metal at that point and bent the two outer tabs perpendicular to the inside of the spring's arc, and the center prong 180° opposite those. A bit of work with the grinder and whetstone brought the tips of these three "fingers" to the same sharpness as the blade on my first scraper, and I duplicated the heat treatment processes used before to harden and temper the second tool's steel.
Naturally, I rely on the single-blade paint scraper to clear flat surfaces. To get at the corners of the walls' overlapping boards, I use the second tool. The middle tooth clears off the upper part of each siding board, then I flip the "depainter" over and scrape the board's lower edges with either of the outside blades, depending on which hand I'm using.
Since the cutting edges are pretty hard, they must be sharpened by grinding or using a hand stone. (I have to combine a liberal use of water with a moderate use of the wheel when grinding, or I'll overheat—and take the temper out of—the metal.) But let me tell you, I've been more than pleased with the performance of my homemade blades. For one thing, they'll probably last a lifetime. And better than that, these heavy-duty paint scrapers have picked up my scraping pace to between 12 and 15 square feet per hour!