Can you mix screws?

[redeye1962]

The old boats typically came with brass screws. Would it be possible to use ss screws or is there a possibility of some type of electrolysis to occur?

[Three P's]

http://www.jamestowndistributors.com/userportal/document.do?docId=267&title=Compatible+Metals+Finder

Check this out, will probably answer most of your questions....

[wizbang 13]

bronze. brass screw boats don't get old. yes times 2

[LongIslandBoy]

Red; Check out "Boatbuilding Manual" by Robert M. Steward, 4th ed., p.76-77. There are many publications out there that cover this same material, but I have this one handy. My take on this is: DON'T mix metals, if possible, especially below the waterline. Hope this helps.

[paladin]

I take it you haven't run across the eloquently illustrated Kama Sutra......it teaches many ways to screw.

[Bruce Hooke]

The old boats typically came with brass screws. Would it be possible to use ss screws or is there a possibility of some type of electrolysis to occur?

Brass screws are generally frowned on for marine work because they loose their zinc and become very weak. Are you sure you are not mistaking bronze for brass? However, if this is a small boat meant for use in fresh water then there is more of a chance that brass screws were used.

Aside from the electrolysis issues, the other reason to avoid stainless steel screws, at least in below the waterline or in other places with low oxygen levels and high moisture levels is that in such environments stainless steel is subject to something called crevice corrosion, which can cause it to fail.

[Paul Girouard]

I take it you haven't run across the eloquently illustrated Kama Sutra......it teaches many ways to screw.



Ya see thats why we need you here Chuck, excellent analysis!


Funny to!:D

[redeye1962]

Thanks for your information. It is what I thought. I have a bad habbit of going up to home cheapo and getting what I can get. There are some hardware stores that have SS material but not sure about Bronze.
My wife and I are planning on getting a larger wooden boat and I am sure there will be some type of rot to fix. I have been learning about mixing metals with my aluminum boat and the difficulty of getting aluminum fasteners so ss is the way to go but very carefully.

[Gary Bergman]

Well, boat repair is a constant cycle; the new screw you put in today, regardless of material, will be taken out in the future and replaced again!
(snot running out me snoz from the Kama Sutra jibe!)

[Ian McColgin]

Actually, many many older boats are iron fastened. If it's real iron you'll need to either refasten with iron (hard to find but fabulous) or not so desirable steel, which is a bit more galvanicly active. I can't see that galvanized fastenings either help or hurt the life span of fastenings in boats, though galvanizing iron and steel hardware above the waterline - anchor chains and cranse irons and such - is a good thing. Steel anchors are galvanized though they are so massive that as the zincing wears off the tips, a little rust does little harm.

Stainless is a good fastening material and can be mixed with older iron.

Monel, if you can find it, is fantastic and manages to be electrically inert with most everything.

You can and should replace brass with bronze but, as mentioned above, look closely. In Europe and by some in Canada the term "naval brass" which means bronze to us is shortened to simply brass, and is fine.

Jamestown was mentioned. Size your fastenings and invenst in a few boxes through them or Hamilton or whatever so that you have the right thing on hand for your repairs. This will give you more suitable fastenings at a price that beats your local litter box store's little plasticized packages of pudendum.

G'luck

[Bruce Hooke]

There are some hardware stores that have SS material but not sure about Bronze.

I don't think I have ever seen a hardware story with bronze screws. There are probably a few in very wooden boat oriented towns where the hardware store is sometimes half a marine chandlery, but as a general rule bronze screws need to be special ordered. Even West Marine, which ostensibly caters to boat owners, did not carry bronze screws last I checked so you can hardly expect your local True Value or Ace Hardware to carry bronze screws.

It is also worth noting that except in rare cases the stainless steel fasteners at your local hardware store are likely to be cheaper stainless steel alloys which will usually do fine for outdoor tasks around the home but will not hold up well in marine environments.

In short, your habit of getting what you can at big box stores and the like is going to come back to bite you.