Floor refinishing by trial and error
We are moving to a house in the country, but before we move in, some renovations are in order. The floor in the kitchen area is very scuffed up, and the plan was to get a flooring company to refinish it. But before that, I figured I'd experiment with it a bit.
I sanded a patch (at right) with my belt sander, then applied some varnish. That spot looked decent, so I figured it shouldn't be that hard to do the whole floor and I should experiment some more.
The idea is that I can push down on it, but thanks to the wheels on the front and the spring, the scraper is still pulled along the floor — because if I tried to push the scraper along the floor it would just dig in.
This scraper had a tendency to chatter in the jig, but attaching a weight to the end of the handle with rubber bands, and with some rubber padding between the handle and the weight, the vibrations were under control.
I also bought some 50-grit sanding belts for my belt sander, and that worked much faster than scraping. So I gave up on the idea of scraping the whole floor. That said, I know it can be done
With just part of the floor stripped, I put a coat of varnish on it to see how it looked. I could see that I hadn't sanded deep enough because with the varnish on it, some of the old scratches in the floor were clearly visible.
After a bit of sanding, I checked the belt and was pleased to see that it showed no sign of wear or clogging. The very coarse belt makes a big difference!
That Ryobi is much lighter than the Makita and probably would not stand up to the abuse of sanding a whole floor, but for this job, it was perfect. And it only cost $100 (Canadian), whereas an edging sander would cost $65 to rent for a 24-hour period. So even if this one got "used up", it would still be an ok deal.
This worked well enough, but maybe I should have worn rubber gloves, because working with construction adhesive on my fingers for over an hour, it took about five days for it to finally come off!
Two days later, with the glue hardened, I used a small hand plane to trim it flush before sanding. I later tried cutting the excess off just with a scraper, and for the 1 mm thick pieces, that worked just as well and was much faster.
I put a hose on the belt sander and hooked it up to my small dust collector (behind me in the picture). The dust collector, with its cyclone, doesn't get the filters plugged up like a shopvac would, and it's also not as loud.
But a lot of dust still got thrown out by the sander, so I set up a box fan to pull air through a furnace filter to help clean the air as I went. I still ended up with a fine layer of dust on everything though.
With several hours of continuous sanding on the belt sander, I'm pleased that I didn't break it!
Also note the weight on top of the sander to get more downward pressure.
This arrangement was not very effective as a "brush" at picking up varnish, but it worked well enough to drag varnish that I poured on the floor across the floor.
I'm working across the boards instead of along them to try to avoid dislodging the dust that I swept into the cracks.
I used up almost a whole gallon can (3.8 liters) on 18.4m2 (205 square feet) of floor. I used an oil based floor varnish, because that's what was on the floor before, and I figured that would stick the best if there was any varnish left in the wood. The oil based varnish is also more resilient (less likely to crack) and better at repelling water than water based varnish.
Once the varnish was dry, I could see all kinds of bumps on it. I'm pretty sure these are from flecks of dust left on the floor because I only swept the floor before varnishing it. Vacuuming would have pulled the dust back out of the gaps.
But this was only the first coat, so I wasn't too worried. It needed a light sanding anyway. But instead of sanding, I went over the whole floor with a scraper to scrape off any bumps. This went fairly fast because I didn't need a whole lot of force, and I only needed to go over each board once.
Initially I thought of putting a sanding pad at the end of a stick to make that easier, but working stooped down like this, I could better see any areas that needed extra attention. There were a few spots where my across-the-grain sanding was still visible, so I used a scraper to scrape through the varnish and smooth those areas out.
At first I thought my gap filling method with the sawdust hadn't worked, so I bought some proper wood putty to fill them with. But then I realized, the gaps were filled, but somehow the sawdust and varnish in the gaps made for very dark lines. I scraped the varnish out of the biggest of the remaining gaps and put wood putty in, but it would have been much easier if I had put the putty in before applying the varnish.
But my mistake this time was not starting at the windows and working away from them. The dark wall in front of me wasn't all that reflective so I didn't see that I missed a few spots. But I was planning on applying a third coat anyway, so no harm in it. The second coat only used up half of a 1 gallon can for the same area.
I still had some bumps after the second coat. This time, I went over the floor with a very flexible scraper to follow the contours a bit better. I also went over it with some fine sandpaper by hand again.
This is definitely not a how-to guide for finishing floors. If you are considering refinishing a floor, unless you are doing a small area, renting a proper flooring sander is the way to go, though a big sander wouldn't necessarily follow the contours of the floor as well, so you'd need to sand off more. You will also need to rent an edging sander to get up to the walls, and for the cost of renting one of those for two days, you could buy a cheap little belt sander, so using a belt sander on the edges makes more sense.
The wood strips as filler for the larger gaps worked well, but it was a lot of work. For gaps larger than 2 mm, I think it's the best way to go. The sawdust in the gaps was less successful. I should have smeared wood putty into the smaller gaps, and vacuumed the floor before applying the first coat of varnish.
But overall, $5 per square foot to have a floor professionally refinished doesn't seem like a bad deal now. I'm sure the pros have this more figured out so they can do this in less time than it took me.
But the homemade flooring sander contraption came in handy later. Once the carpet was ripped out of the rest of the house, there were all kinds of bumps and pet urine stains to sand out of the plywood to make sure the new hardwood flooring would go on as flat as possible to avoid future squeaks.
And the homemade "squeegee brush", without the shop towel, was very useful for sweeping the subfloor. The straight board got caught on any nail, staple or bump, so it was a good way of finding stuff that needed attention.
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