Intro: Curved Surface Paint Scraper
I have an old wooden kitchen worksurface which I want to strip and use for another project. The backboard has a curve where it meets the worksurface, and a flat paintscraper would not work for getting in there.
There were no suitable tools in any of the paint stores, so I had to make my own.
A large washer from the junk box had exactly the right curve to get in there, so that, plus some M6 threaded rod and various fixings were pressed into service.
M6 threaded rod
Huge M12 washer from the junk box
Step 1: Assemble Tool Head
The tool head, comprising the scraper blade, the shaft, and the various bits connecting the two were assembled.
First, I cut a six inch chunk of M6 threaded rod, using this wonderful 'Ible to get a clean, quick cut.
The large diameter washer which would be the blade was too loose on the shaft, but a couple of narrower washers neatly filled the gap.
A padding washer on either side held everything together, and then the nuts which lock everything together were tightened as hard a possible.
Step 2: Make Tool Handle
I was really lucky in that my scrap pile had a six-inch length of lovely hardwood broom-handle, complete with a metal ferrule.
I needed a hole drilled in the end of the handle to accept the threaded rod of the tool, and it had to be co-axial with the handle.
To try and achieve this I clamped a vertical guide underneath my drill-press and held the dowel against that while I drilled a hole about 1mm wider than the threaded rod.
After the hole was drilled, I used a couple of grades of sandpaper to smooth the outside and give a nice feel to the handle.
Step 3: Fit Tool to Handle
To hold the tool in the handle, I used two-part epoxy.
Whichever brand of epoxy you use, read and follow the instructions, especially any notes about local climate. It's winter here and freezing cold, so that gave me a little more working time.
Following the instructions on the resin, I squeezed out matching amounts of the two components onto a clean, smooth piece of scrap timber, mixed them thoroughly with a piece of thick wire and then left them to stand for fifteen minutes.
Then I used the wire to scrape the epoxy into the hole in the end of the handle, and once it was all there I inserted the threaded rod of the tool and left the resin to cure for a day.
Step 4: Sharpen Tool
To give a good edge for lifting softened paint, we need to put an edge on the metal disc. To encourage the scraper to lift, rather than smear, the paint, we need to take material from the trailing edge of the blade.
This would most easily be done by working the trailing edge of the blade against a bench grinder, but since I don't have one, I fitted a metal-polishing disk to my angle-grinder and clamped that in a portable workbench.
For a tight curvature like this, it is much easier to get a smooth grind by manipulating the workpiece than by trying to manipulate the tool.
I held the blade of the scraper against the grinding disk and rotated the handle of the scraper to get an even chamfer on the trailing edge of the scraper blade.
Once the blade shape was right, I removed the burr from the workpiece with a medium cut file.
Step 5: Summary, Mistakes and Learnings
This tool is absolutely perfect for scraping the curve at the internal angle on the wood. I was extremely lucky that I had a washer the exact right curve to make this. The internal hole in the middle of this washer was so large that it would have slopped around on the shaft, but through another stroke of luck, I had a couple of washers whose internal diameter matched the rod, and whose external diameter matched the inside of the washer which would be the blade. The take-away from this, is to have a big box of random washers.
As you can see from the first photograph, the hole is a bit skew-whiff from where it should be. Rather than holding the rod against the upright guide when drilling, I should have spent longer to get everything clamped and held rigidly in the right place.
The second photograph shows me pushing glop into a tiny hole using some wire. Next time I might spring a dollar for a syringe from the pharmacist so that I can load it up, then inject the resin quickly and more cleanly.