Brass vs bronz screws?

[pwilletts]

I need to attach a main sheet swivel cam to the deck on my 24' sailboat
I will use either through bolts or screws..not sure yet...finding bronze in small quantities is difficult....is brass a bad choice? I will use 4 of whatever

[skipmac]

Not sure what a swivel cam is but if there is any force on it to speak of, through bolt it. Use a backing plate or large washers on the inside.

Brass if exposed to salt environment will pretty quickly turn green and corrode away. Bronze is a little better but still won't last forever soaked in salt. Both of these do depend to an extent on which brass or bronze alloy.

If exposed to the environment I would probably go with stainless. Just make sure the bolts or screws are well bedded so moisture can't collect around the threads.

[skipmac]

By the way, what country are you in? Your avatar doesn't mention. If you're in the US Jamestown Distributors has a pretty good selection of bronze fasteners and will sell you even ones or twos online. Shipping might make smaller quantities a little costly but hey, it's a boat. Everything is costly.

[LoudMusic]

Originally Posted by skipmac

Not sure what a swivel cam is but if there is any force on it to speak of, through bolt it. Use a backing plate or large washers on the inside.

Brass if exposed to salt environment will pretty quickly turn green and corrode away. Bronze is a little better but still won't last forever soaked in salt. Both of these do depend to an extent on which brass or bronze alloy.

If exposed to the environment I would probably go with stainless. Just make sure the bolts or screws are well bedded so moisture can't collect around the threads.

I completely agree; through-bolt stainless with a backing plate.

[wsmurdoch]

Originally Posted by pwilletts

...finding bronze in small quantities is difficult....

Try:

https://www.boltdepot.com/

They are a "lemons to lemonade" story. They filled a need.

https://www.boltdepot.com/about/Story.aspx

[Cheechako]

Stainless, thru bolted with large washers or a plate.

[roverhi]

Bronze is a way better material in a salt environment than SS or Brass as long as the fasteners are sized to meet the load. SS is prone to crevice corrosion and very susceptible to work hardening if flexed, Brass is an alloy of copper, zinc and other stuff. The zinc acts just like the sacrificial zincs on your prop and shaft, it gets eaten up leaving a sponge like weakened fitting or fastener. Brass is acceptable above the water line but should never be used where it will be constantly immersed in salt water. Silicon Bronze doesn't suffer from these maladies and expect for it's slightly lower strength than SS is a way better marine material. Unfortunately it's pricier than SS so has gotten hard to find.

If the load on the Swivel cam is primarily shear and not heavily loaded, you may get by using screws. If it is possible to through bolt, better to go that route with fender washers or backing plate depending on the anticipated load.

[Benz]

I second Roverhi's answer. Brass is bad; stainless is to be avoided unless going into aluminum; silicon bronze is the best option most of the time. My local West Marine has a decent selection of sil bronze in stock, but it is a "flagship" store.
By all means through-bolt, and bed with 5200, the only bedding compound I've found reliable.
Ben
zartmancruising dot com

[skipmac]

Originally Posted by Benz

I second Roverhi's answer. Brass is bad; stainless is to be avoided unless going into aluminum; silicon bronze is the best option most of the time. My local West Marine has a decent selection of sil bronze in stock, but it is a "flagship" store.
By all means through-bolt, and bed with 5200, the only bedding compound I've found reliable.
Ben
zartmancruising dot com

Stainless into aluminum is a huge problem unless you use Tefgel, Lanocote, Loctite or some other kind of goop to electrically insulate the SS from the Al. If you don't, a couple of years down the road the SS fasteners will be permanently and irretrievably frozen into the Al by the galvanic interaction between the two metals.
,

Over my years of boat ownership I have had to drill out, grind out, cut out and otherwise mangle Al things like masts, hatch frames and such to get out the SS fasteners that had welded themselves into place. I have tried every kind of penetrating, freeing, loosening chemical and technique known to man included soak and heat, soak and beat, soak and heat and beat and repeat. Have used superheating and still end up drilling out the majority of the SS fasteners.

Bedding, for 99% of the bedding I use butyl tape. The stuff is fantastic and you can get it off again if you need to without using HE.

[Scott Berg]

In the US Fawcett Boat Supply in Annapolis, MD purchased Chesapeake Marine Fasteners a while back; have a huge collection of bronze fasteners and ship everywhere.

[Cheechako]

The deck fitting is likely SS. I would use SS screws. It should all be sealed up with goop anyway. I love bronze for a lot of things, but if you have driven enough bronze small screws, you know they shear off far easier than SS do... in the same size.

[buzzstar]

Although you asked about brass or bronze, and stainless steel (probably 316) has been included in the responses, you may wish to look at titanium (with a backing plate, as with any piece under load). I have no affiliation or other direct or indirect interest in the company, except a personal fascination with the material, but it seems a source for boat and yacht stuff, including fasteners, is Allied Titanium - Affordable Titanium Now. Expensive, perhaps, but there is no way to know without looking.

BTW, the manufacturer and/or the seller of the swivel cam may have some size recommendations for the deck fasteners. If you do not want to identify them or do not know, at least determine the measurements and look on line, if you are able, to see what is provided as the for something comparable even if it is not the identical product.

[zeehag]

wow stainless into aluminum... asking for a freeze up and mayhem.
but you all have spouted that you know more than do i, so keep it up. personally i choose something more kindly and easier to dismantle , as i know no one prevents the electrolysis that WILL occur.

[MCOS]

Originally Posted by pwilletts

I need to attach a main sheet swivel cam to the deck on my 24' sailboat
I will use either through bolts or screws..not sure yet...finding bronze in small quantities is difficult....is brass a bad choice? I will use 4 of whatever

Brass is an alloy of mostly copper and zinc.

Bronze is an alloy of mostly copper and tin.

Bronze is the most likely best choice for your indicated usage. It is more inert in water usage.

Have you considered stainless steel? Stronger and probably easier to find.

[Jim Cate]

Good grief, folks... we're talking about a simple cam cleat on a 24 foot boat Titanium screws??? Worrying about electrolysis in aluminium??? He's not told us what material the deck is made of, but I bet it isn't aluminium...

So, for the OP: The advice to through bolt is sound, but it will not really matter what material the bolts (machine screws) are made of... at least nt in the choice between s/s and bronze. Either one will do just fine if they are sized appropriately. A simple way to judge that is to use screws that just fit the holes in the deck plate on the cleat. If the deck is GRP, you need to know if it has a balsa or other core material in it. If balsa, it's a good idea to replace the balsa in the region that is compressed by the screws... there has been heaps of good advice on this subject here on CF, so a bit of research could help you. With regard to your original question, I'd avoid brass hardware or fasteners anywhere on a boat, especially if used around salt water. Just not worth the risk of rapid decay.

Jim