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Making Curved Railings - Continued

The Balustrade Railing

The lower balustrade railing was a different story. It was too beefy to make with a router and a trammel arm. Instead, I ordered the rails pre-bent by the manufacturer to the radius required. The plans specified every radius on the house. Just as with the spindle railing above, all I had to do was subtract the distance from the edge of the deck to the center of the posts. I then used that center measurement to order all the rails.

Fypon manufactures straight balustrade railing embedded with a 3-inch-diameter steel pipe, so the typical 8-foot to 9-foot spans between my posts were stiff and rigid. But Fypon’s bent railing is formed around 3-inch PVC pipe, obviously because PVC is easier to bend. I would have preferred steel pipe in the radius sections, but with the 1/4-inch steel cable supplied by the manufacturer, we were able to stoutly reinforce the long spans.

Layout and cutting. We were able to reuse the template we’d used for the spindle railing because the radius was exactly the same. After marking the top and bottom rails for each section, I used my miter saw to cut the PVC embedded railing.

We laid out the balusters in the same manner, though the end balusters were centered 2 1/2 inches in from the ends of the railing because the spacing was 5 inches on-center (Figure 5).

Drilling. Fypon balusters are formed around 3/4-inch aluminum pipe, with the pipe extending from the baluster by 1 to 1 1/2 inches. For drilling the 3/4-inch holes in the railing, I experimented with several types of drill bits on both the PVC and the steel-embedded railings. I found that a 3/4-inch hole saw worked best on both. I thought I’d have to stop the drill every three or four cuts to clear the hole saw, but strangely enough, after two or three holes, the compressed polyurethane inside the hole saw acted like a spring and pushed out the waste, which we then removed from the spinning hole saw with a small stick.

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Figure 5.Balusters for the main railing were laid out on 5-inch centers (left). A hole saw in a drill press made for fast, accurate boring in the PVC radius railings (right) as well as the steel-reinforced straight rails.

Assembling the Railings

Assembling the railings’ lower baluster was a little trickier than assembling the spindle railings. We started at the bottom rail, applying a liberal amount of Fypon adhesive around each hole, then inserted the baluster (Figure 6). After squeezing each baluster tightly against the railing, we toe-nailed each one with 2 1/2-inch galvanized nails.

Next we added the top railing, starting at one end and slowly working each of the balusters into its hole. Then we turned the section upside down and used 5-foot Bessy clamps to hold things together. The deep plastic jaws reached well over the railing and didn’t mar the polyurethane. Once the entire section was snugly clamped, we toe-nailed the top balusters, too.

I learned the hard way that I had to let the adhesive dry before moving and installing the balustrade, because the mixture of nails and polyurethane wasn’t strong enough to secure the joinery. Once the adhesive dried, the pieces were practically welded together.

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Figure 6.When assembling the Fypon railings (left), 2 1/2-inch galvanized finish nails, four in each baluster, provided temporary security until the polyurethane adhesive dried. Fitting the top rail (right) was tricky and required two sets of hands because of the varying lengths of the 3/4-inch pipe projecting out the end of the balusters. This required finding and setting the longest dowels first.

Threading the Cable

Before starting the installation, we drilled a 1/2-inch hole through each of the porch posts, exactly at the center of the top railing, then passed a fish tape through each hole with a pull string attached. We did the same with each section of the radius railing, leaving a pull running through the hollow top rail.

Starting at one end of the railing, we pulled the 1/4-inch steel cable through each post and railing section until the cable reached the opposite side of the last post. Then we installed all the railings on L-clips, first applying a generous amount of adhesive on each end.

After all the railings were mounted, we slipped several fender washers over the dead end of the cable, secured the loose end with a compression fitting, then pulled the cable tight with a come-along until it sang like a piano string (Figure 7). In fact, we had to release a little tension on the cable, because it began to flatten the radiuses.

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Figure 7.The PVC radius railings rely on a tensioned steel cable for strength (top). A come-along provided the necessary pull (bottom). The 3-inch hole where the cable is cinched will be covered by a removable section of straight railing, should the cable ever need retensioning.

Before starting the installation, I drilled a 3-inch-diameter hole into the last post so we’d have room to tighten the compression fittings. Once we were satisfied with the tension on the cable, we locked it down but didn’t cut the cable. Instead, we left the end long and looped it inside the oversized hole. The next section was straight railing, which didn’t need to be fastened with adhesive. The end of the straight rail would cover the hole, but if the cable ever loosened, I’d be able to access the cable to retighten it by removing that section of straight rail.

Gary Katzis a finish carpenter in Reseda, Calif., and author ofFinish Carpentry, a JLC book.