Installing New Stanchions

with Backing Plates

 

Garhauer ST-36 premium gate stanchionGarahuer ST-52 premium stancion, draw base, heavy tubing

I purchased custom replacement stanchions from Garhauer. I called Garhaure first, and compared the location of the holes in the base to my exiting stanchion. The measurements they gave sounded like the trapezoidal shaped bases would match the existing holes perfectly -- but when they arrived they were off by 1/8" or so.

I ordered two of style ST-52, 3 degrees out, for the bow; two of style ST-52, 3 degrees in, for amdiships; and two gates with legs, styleST-36, two degrees inward. These are Garhauer's premium quality style stanchions, with drawn bases and thicker wall tubes.

I chose the bases trapezoidal-shaped bases, drilled/punched for carriage bolts rather than machine screws. It makes it a little easier to install them by myself; I don't need somebody on the outside to hold the bolts when I tighten the nuts.

I also purchased trapezoidal shaped backing plates from Catalina Direct, for under $4 each. The holes in the backing plates matched the new stanchion bases from Garhauer. When they arrived, I though they were aluminum. But when I asked my metal worker to shine them up a bit, he realized they were stainless. They took on a high shine in just a few minutes.

 

 

Preparation: I removed the old stanchions, bolts and nuts.. I cleaned the old polysulfide bedding material off the deck with a stainless steel brush. I removed old bedding from the holes with a 1/4" drill bit.

The Plan: I considered the problem of installing a backing plate. The problem is that the cabin liner has a lip that makes it impossible to install a backing plate without modification.

I decided to cut away the lip and build up the underside to make a flat area for the backing plate. After cutting away the lip, I would use DynaGlass to build the up a flat area so the backing plate would have a flat bearing surface. (DynaGlass is marine grade polyester with short glass fibers mixed in. Before curing, it has a viscosity somewhere between mayonaise and peanut butter.)

Cutting the liner: I suspended a backing plate onto four long bolts and traced the outside onto lip. Then I used a ceramic cutting wheel on a rotary saw to make the cut-- it made the cut in just a few seconds. I smoothed the edges with an abrasive wheel.

(I made the cuts about 1/4" too wide and will have to touch them up with thickened gelcoat.When I do the next stanchion, I will make the initial cut-out narrower and then use the grinder to make it wide enough. Practice makes perfect, they say... oh well, a little gelcoat will make things look just fine again... )

Drilling new holes: Before cutting or drilling anything, I needed to check the location of the extra leg on the new gate stanchion. I put the new stanchion over the old holes and checked the alignment of the four holes in the stanchions base position of the support leg. I realized that the gate's support leg would have to be as far outboard as possible to avoid cutting the lip of the ceiling liner inside. If I placed right up against the toerail, I wouldn't need to cut the liner there to install a fender washer for a backing plate. I could use the existing four holes for th ebase if I moved them outboard about 1/8" further.

After checking the hole placement, I enlarged the existing four holes to 3/4" diameter. I placed the new stanchion in place and dropped 4 bolts thru the holes. After alinging the gate stanchion, I drilled a 1/4" hole for the supporting leg, using the stanchion as a template. I removed the bolts and stancion, and enlarged that hole to 3/4" diameter too.

Fabricating solid epoxy fillets: I covered the bottom of the holes on the inside of the cabin with masking tape and mixed up some West epoxy (one pump). I painted the inside of the holes with plain resin, then thickened the remaining resin with 404 thickener. I filled the holes with the thickened resin and let it cure overnight. In the morning, I placed the stanchion over the fillets and drilled new holes. The solid epoxy fillets will prevent wood rot even if the stanchions leak in the future.

Casting the backing surface, made of DynaGlass: The picture above shows the finished surface after casting it in place. The dark stuff is the dynaglass. The finished surface is perfectly flat on the bottom. It varies from 1/8" to 1/4" thick as it spans from the liner to the underside of the deck.

First I cleaned the underside of the deck with acetone to remove any dirt, grease or wax. I put the backing plate up against the underside of the deck and held it there temporarily with nuts. I put masking tape around the outlne of the backing plate to keep the DynaGlass from getting smeared on the underside. .I removed the backing plate.

Next I coated the parts so they could be removed after casting the resin. I sprayed the bolts with releasing agent (Pam cooking spray works great.). I covered the top surface of the backing plate with masking tape and then coated it on both sides with releasing agent. I also waxed up egular nuts to go onto the bolts.

I put the stanchion on the deck, with the bolts hanging down thru the four holes in the base and the single hole in the support leg. I was ready to mix up the DynaGlass.

Next, I mixed up about 3 tablespoons of DynaGlass with about 1" of creme hardener. I spread it onto the taped and waxed surface of the backing plate about 3/8"" thick everywhere. . Then I carefully pushed the backing plate up, aligning the holes so the bolts dropped thru the plate, and pressed the plate firmly and evenly up against the uderside of the deck. I pushed the plate up just enough to sqeeze out excess DynaGlass, leaving a thin, flat surface everywhere.

Finally, I threaded a couple of the waxed nuts onto the bolts to hold the plate securely while I wiped off the excess DynaGlass, leaving a clan margin around the backing plate. I removed the masking tape, leaving a nice clean edge.

 

The DynaGlass cured completely to a hard surface in approximately 30 minutes at 60 degrees F. I removed the nuts, popped the backing plate off the cured DynaGlass, and pushed the bolts out.

These are pictures of the cured DynaGlass surface,without the backing plate or bolts. You can see that there's a perfectly flat and smooth surface for the stainless steel backing plate to press against.

To finish the project, I removed all the release wax, bedded all the bolts with 3M 101 Sealand (polysulfide) and cleaned everything neatly with denatured alclhol.

For cosmetic appearances, I still need to cut off the extra length of bolt and I will have to touch up the cut edges and over-cut marks with gelcoat. Next time, I'll be a little more careful with the rotary cutting wheel (or perhaps finish the cuts at the corners with a jigsaw), so I don't have as much touch up to do. I'll get pics of the finished project.

There's a lot more room to get past the gate stanchion now!

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