Bronze stanchion bases, stainless bolts?? help please!

[sail_girl91]

Hello all! I am in the middle of a massive remodel on a very worn out old boat. This is my first sailboat and she's a real fixer-upper! I am not super knowledgable about sailboats, and have been very much "learning as I go" which can be very confusing and frustrating at times, to say the least! Right now I am looking at reinstalling our stanchion bases. We have what seems to be either stainless steel or aluminum stanchions, but we have bronze bases which had been painted previously. We just cleaned and repainted them with an epoxy paint, and are now trying to prep for the reinstall. The problem is, when we purchased the boat the entire deck had been stripped of all hardware and the holes had been filled. So we don't know what kind of bolts were on the deck in the first place. We were hoping to use stainless for the backing plates and stainless bolts, but is that not possible because of the corrosion?

[skipmac]

Most typical bronze alloys will be pretty much compatible with most any stainless alloy you're likely to have on your boat.

If you want to use SS backing plates and SS bolts to hold the stanchion bases down that should be just fine. Wouldn't hurt to put a little something on the bolt threads regardless. Lanolin, Lanocote or Tefgel would all work.

The stanchions are probably stainless as that is by far the most common but could be aluminum. A quick and dirty test, aluminum will scratch easily compared to SS. Take something with a sharp point and try it in an inconspicuous place.

[skipmac]

One more thing. When you put the bases down bed them with butyl tape. Best stuff going for the job.

Drill the holes for the bolts, make a small countersunk around the top of the hole in the deck, put the bolt through the base and cover the base with a think layer of butyl tape. Wrap a little extra around the bolts where they project through the base. Push the base down onto the deck, thread the backing plate under the deck and tighten the nut including a washer and lock washer. Best to tighten a little to start, let the butyl ooze a bit, tighten some more. Repeat 2-3 times.

The butyl should squeeze out all around the edge of the base. Trim off the excess.

There are different grades of butyl tape. Some is junk. In general gray seems to be the best but to be sure buy from here ***Buy Bed-It Butyl Tape*** Photo Gallery by Compass Marine How To at pbase.com

[skipmac]

PS

Welcome to the forum.

[clockwork orange]

Stainless bolts are fine with the bronze bases but there is nothing to stop you from ordering silicone bronze bolts online if you want to, i would use 1/4" G10 (epoxy impregnated fiberglass sheet) or FRP sheet (polyester impregnated fiberglass) instead of ss for the backing plates and epoxy them in place and make them as big as practical. You can buy it from Mcmaster- Carr among other places.

Steve.

[clockwork orange]

Good instillation tips from Skipmac. Im pretty sure your existing stanchions will be SS if the bases are bronze, as you would not use bronze and aluminum together in a marine environment. Another thing to watch out for is that none of the bolts go through core, i have found quite a few situations where the inboard bolts go through the tapered edge where the builder closed the core out, so look carefully and be sure there is no wet core from the original install.

Steve.

[MarkSF]

Originally Posted by skipmac

One more thing. When you put the bases down bed them with butyl tape. Best stuff going for the job.

Drill the holes for the bolts, make a small countersunk around the top of the hole in the deck, put the bolt through the base and cover the base with a think layer of butyl tape. Wrap a little extra around the bolts where they project through the base. Push the base down onto the deck, thread the backing plate under the deck and tighten the nut including a washer and lock washer. Best to tighten a little to start, let the butyl ooze a bit, tighten some more. Repeat 2-3 times.

The butyl should squeeze out all around the edge of the base. Trim off the excess.

There are different grades of butyl tape. Some is junk. In general gray seems to be the best but to be sure buy from here ***Buy Bed-It Butyl Tape*** Photo Gallery by Compass Marine How To at pbase.com

This is great advice but a further refinement is to drill the holes oversized, countersink them, fill with epoxy, then drill the correct sized holes, then countersink again. This leaves the core sealed off by epoxy, even if the bedding leaks.

[sail_girl91]

Thank you all for the quick response!! These are great tips, definitely going to look into everything! I was so stressed about the metal mixing issue, so knowing that if we go with stainless, there won't be an issue with it! Thanks again everyone for the help!

[MarkSF]

One more tip : Make the holes in the backing plate a little oversized, to compensate for misalignment of the bolts.

[GordMay]

Greetings and welcome aboard the CF, sail girl.

[Scout 30]

It's not necessary to paint bronze or stainless steel.

[Cheechako]

Take care to figure out where the backing plates will be on the inside of the boat. If you have any deck core in that area you will need to seal each hole to avoid water ingress into the core. Often you will have two holes in solid uncored glass on the outside and two thru core on the inside (closest to the boat centerline). If your boat had all the holes filled, take a good look.... it could have been built with solid glass at each location where the stancions go... although unlikely.
What kind of boat is it?
I would use SS bolts if I were you. I've found bronze machine screws to be brittle and break easily in 1/4" and down. easy to break them just tightening them.

[sail_girl91]

She's an old 1972 36' Dickerson Ketch...she's super sturdy, just needs some TLC. We are most definitely leaning toward stainless... That's what we wanted originally but then someone brought up the issue with the different metals. So, now I'm gal we can go back to the original plan

[clockwork orange]

What you are looking for are metals which are reasonably close together on the galvanic series chart, most open body turnbuckles for example will have bronze bodies(sometimes chrome plated) and ss for the male threaded part. Please make sure that you use type 316 stainless bolts, not the 304 commonly available at the hardware store. You may have to order them online. I agree with someone earlier that painting the bases was probably not a good idea as it does not need anything to protect it but the paint will eventually fail. Should be a cool old boat when you are done.

Steve.

[Cheechako]

Originally Posted by sail_girl91

She's an old 1972 36' Dickerson Ketch...she's super sturdy, just needs some TLC. We are most definitely leaning toward stainless... That's what we wanted originally but then someone brought up the issue with the different metals. So, now I'm gal we can go back to the original plan

That boat may have uncored sold decks. Not sure... you will know soon. Bronze and SS should be fine. Most boats built have 304 SS. The latest trend is 316 and it's a little better.