Stainless steel screws under epoxy !?

Well, I said as much in the first post. But I'm sorry, if it wasn't clear enough.

Hmm, now that you understand that it's not MY boat we're talking about, I would assume you would have read the first post. No, I'm amazed that a professional boat builder would use stainless screws for the permanent parts. Hell, I even quoted that part. Did you not read the first post?

Surely I don't need to take courses from you about crevice corrossion, since you still haven't got it. Please read up on it, and your "perspective" won't be different from anyone else who understand crevice corrosion. Hell, I even provided a few links for starters.

Anyway, anyone can teach, but it is a poor teacher that is unwilling to learn.

 

Danish you don't get it

Danish you don't get it

Have you done an experiment to see whether 316 or other stainless will degrade under epoxy? I understand about the simple theory on crevice corrosion. I come up with a different point of view under epoxy. Until you can point out a link and study where stainless exhibits corrosion under a layer of epoxy then calling me names by insunuation will not be called for. Do the experiment as I said earlier if you want. Get some stainless and shove it under epoxy. Wait and see if there will be any corrosion.

In my pulling apart of bits of my cats I have never seen stainless corrode under an epoxy layer. I have done an experiment of sorts - that is why I differ from you.

Danish - I have never called you silly or insinuated that you are stupid or stubborn. I usually get the same respect back from my other forum members.

I am out

Phil Thompson

 

I don't need to do my own experiments when I have seen stainless under epoxy go all black and corroded. And yes, in theory, it would work well to cover it with poxy, but in reality it doesn't work like that.

But you telling me it might be useful for me to take a course from you is all fine and dandy?
Anyway, I already gave people a few links. Crevice corrossion is well understood, and is hardly something I will need to show multiple analysis and studies in order to convince people like you. ou might as well deny cathodic corrossion existed, unless I could provide you with analysis and studies, when in fact, you should simply have read a bit more and seen a little more.

Go out and see what crevice corrosion can do. Then you won't find it necessary to do a somehwat lackluster experiment as the one you're suggesting.

Really? Why would I need to conduct my own experiments, when people like you are willing to put stainless underwater in places where it will be oxygen starved? You obviously haven't read even the first post yet.

Really? I consider your patronising tone all the while offering to give me a course - this after your attempts to play the "I'm a teacher"-card insinuating loads of things.

Besides, the mere mention of that, is like me saying:

I never called you a stubborn, ill-researched pretender, nor did insinuate I would never buy anything from you, as you obviously haven't got a clue.

Unlike what you think, it _is_ what you say, not _how_ you wrap it.

To check on your epoxy?

 

Hi Dannish,

Since all woods 'breathe' and are porous you may well find that the SS is going to survive. If the SS was enclosed in epoxy that could have been another matter. I have seen SS screws removed from wood after being in there for years and years... never saw an oxy one.

I assume the screws were used only for keeping the part(s) in place prior to epoxy / glassing it over - if the srews totally disintigrate, would it contribute to a weekness in the structure ? Probably most likely not.

If I was you, I wouldn't even worry about it, unless some problem is showing up because of the SS screws specifically...

 

Oh, Fanie (boy /from glen to glen/ and down the mountainside/just kidding, Fanie )

I cannot emphasize how necessary it is to read the very first post in this thread. That is what it is about.
http://www.boatdesign.net/forums/showpost.php?p=203141&postcount=1

Also, another post of interest, since I apparently must have a hard time communicating these days ;-) is this from Par:

http://www.boatdesign.net/forums/showpost.php?p=203292&postcount=25


Now, since this thread is beginning to annoy me, because people seem to dismiss oxygen starvation, I hope people will read the links I posted here, begin from the bottom, as I chose to put them in that order:

http://www.boatdesign.net/forums/showpost.php?p=203161&postcount=10

 

Imbedded in epoxy or not, corrosion will take place and why bronze is hands down the preferred material, under the LWL. There are many technical reasons for this, but in reality, compared to speculation based on commonly accepted theory, generally don't equal the same results, particularly in the marine environment. Speak what you know, not what may be potentially true in a perfect word or in an engineering thesis.

Many of us here have disassembled dozens of boats (I've worked on hundreds), many with mild steel and stainless fasteners. A chorus of voice suggesting "get the steel out" is easily heard if these folks are asked, which apparently has occurred here. Again, speak what you know folks, not what is supposed to be true or what you think you know, preferably in a reasonably civil manner or take it to the open discussion forum, where yelling and dissention is desirable and often prompted.

 

Well, since you don't believe - which is ok - at least I got you in a 'just kidding' mood.

You should drill those SS screws out immediately, replace with brass/ bronz and epoxy the holes shut again, especially the below waterline ones.

Just kidding

What did you have in mind to do then Dannish ?

 

The point I was making, even if you have tied those strip planking down with thin pieces of wire and they have already evapurated, or oxidized away and are held into place now by the epoxy, would it be a problem ?

So even if you have used any kind of tie down material it would make no difference. Bronz would last longer, but what difference would it make?

The epoxy and the wood is now one piece forever... the method of initial tie-down of the strip planking is unimportant.

 

Any piece of metal in a boat is a potential problem
I'll think I ripe the screws away and put wood nails instead:idea:
Maybe in the next boat

 

If it is something that would not contribute to strength or structural strength it would not matter what you use. As Teddy said it can be even nails although they would probably just pull out at exactly at the wrong moment which would be when the glass / epoxy is still wet

If it is something that has to add to structural strength then there are other things to consider - you don't want a piece of SS elsewhere (breathing fresh air of course) to react to your prized piece of bronze and have it corroded away. I have an article somewhere that describes what the metals do to one onother if conductivity between them occurs. If I remember right, then SS is the dominant metal in this case that will cause the bronze to corrode.

If that was my boat I was building, I would probably use cheap screws. In the strip planking they lose their value after the glass/epoxy dried, so weather they are there or not wouldn't make any difference.

If you built your boat using the bronze, then good. Just remember in a year or so my boat is going to be a kilo or so lighter when my cheap screws rusted away

Paranoid? Mmmm... lemme think.

It is a good thing to want to use the right thing instead of just using anything.

 

That was a question Ted, as denoted by the question mark as I was unsure. If the first reply had been a little more precise half the conversation would not have occurred.

If its a strip plank boat I am not sure I really understand the need to leave any fastening in place. I'd want to see what is actually being done and why the pro builder has left ss in the planks in the first place. As I pointed out before they should be redundant... but? I'd be really tempted to work out what needs to be done to remove the need for any structural metal fastener.

 

Nails, brads and sometimes staples are used to hold the strips in place on top of each other as the clue sets, after which they are redundant and a potential source for future concern. In most cases they are left in place, other wise you'd only be able to do one strip at a time, because you'd have to wait for the glue to set before pulling them. Most pro's don't bother with them, preferring to nail to the station molds and fill the holes later. If a bright finish is desired, then there are other methods, that don't leave holes, one of which is shown in the latest WoodenBoat Magazine. I use plastic staples, which sand down just fine during fairing.

 

PAR,

Nice to see some educated responses on this web site, I am getting tired of the crap that some people write, obviously from very little practical experience. There are always plenty of arnchair admirals about.

I recommended this site to a mate of mine who is also working in China not far from me, he was disgusted by the comments and has not bothered to post for a month now....I still read, but could not be bothered getting involved in some of the nonsence being spewed as Boat Design information. Please, if you folks want to talk rubbish, keep it to the rubbish folder, don't contribute it to other postings where some of us are actually very interested in the boat building game.....

 

Plastic staples sound good, we stapled through packing strip when building dinghies, then just pulled the staples out with the packing tape. Old trick I am sure, don't know how well it would work with heavier staples.

 

pulled my thread ,,didnt know there was a pissing match going on ,,but got a question anyway ,,first of all ,,someday I will learn to read the entire thread before commenting,talked to par earlyer on about ss316,,my boat has some ,,the lead ballast is held on by 8 ,,7/8 ss bolts that go through the keel and keelson,,I want to glass over the lead and seal it up ,,but not cover each indivdual bolt and then put them back in ,,you guys seem to be talking about a temporary use of the ss to hold the planks in place untill you glass over??so it dont seem to matter if they survive,,am I correct so far,,?should I be worried about my ballast falling off ,in a year or ten?,,not to get off track,,but have also heard the myth that if you seal wood ,you put it in a coffin ,,mine has been sealed since 1967 wood looks like new,longliner