cali27
Well-known member
Just an FYI. I just came from the "Bolts plus" store looking to buy ss tapping screws for my upcoming mod. Everyone that worked there told me never to use ss with aluminum.
TinBoats.net
The original aluminum boat site!
Stainless steel screws
- Thread starter cali27
- Start date
Help Support TinBoats.net:
dyeguy1212
Well-known member
Theoretically it can cause corrosion, but I've never seen it happen.
Wait, is there anything that doesn't react with aluminum :lol:
Wait, is there anything that doesn't react with aluminum :lol:
...At which point you responded with, "Well what do you recommend I use Mr. Boats Plus sales fella," didn't you?
Just what did he recommend using?
Just what did he recommend using?
Troutman3000
Well-known member
dyeguy1212 said:
What do you use then? Wood Pegs :lol:
cali27
Well-known member
They said just to use the regular metal screws. They also said that the ss would rust quicker because of the way it reacts to aluminum.
cali27
Well-known member
it's called Bolts plus. Nice attempt at humor thoughbassboy1 said:
dyeguy1212
Well-known member
cali27 said:
Regular metal? I just checked the periodic table.. "metal" isn't an element... :lol:
How's that for humor?
I'd rather use SS and worry about corrosion (which I've never seen happen) vs buying regular "metal" and dealing with rust and rust lines from water dripping.
perchin
Well-known member
dyeguy1212 said:
x2 =D> I've myself used SS carriage style through aluminum and never had them rust out. :!:
Truckmechanic
Well-known member
As long as it was above the water line and zinc plated I see no reason why it would hurt.
dyeguy1212
Well-known member
perchin said:
Do you mean corrode? Because SS is designed to not rust? :wink:
perchin
Well-known member
Truckmechanic said:
do you mean zinc is better than SS???
Wondering cuz the trade I'm in I use hardware daily and have never found zinc to hold up in any conditions for more than a couple years. I'll stick to SS
dyeguy1212
Well-known member
perchin said:
I was thinking the same thing, but I'm no expert
cali27
Well-known member
sorry guys, i did not know how many metal experts we have on here! Also sorry for not taking notes at the fastener store. I like to listen to people that know what they are talking about, therefore i will not use stainless steel screws. Sorry for even starting this post. It was not a shot at anyone who has used the ss.
dyeguy1212
Well-known member
I don't think anyone saw it as a "shot"...
Its not even like theres a debate.. people are just saying what they've used, and you brought up an interesting topic.
So whats the issue?
Its not even like theres a debate.. people are just saying what they've used, and you brought up an interesting topic.
So whats the issue?
perchin
Well-known member
cali27 said:
I did not take it as a shot..... just saying I do a lot of buisness with fastenal, and they have never steered me away from SS. as for your post, don't post if you don't care about our opinions.
cali27 said:
I'm assuming by regular metal, that he is speaking of medium carbon steel screws and bolts (I'm talking grade 2 - grade 8 bolts and most screws sold today). These are all zinc coated. Now, ON PAPER, aluminum with zinc is a much better match than aluminum with stainless steel, which would be the case, IF the aluminum and ss quantities, or the aluminum and zinc quantities identical.
On the aluminum and stainless side of things, the stainless will be the cathode, and the aluminum the anode, due to stainless's lower reactivity. The cathode is the more noble metal, and the anode is the active metal, or the one you will see the corrosion on.
With aluminum v. zinc, the aluminum, having a lower reactivity, will be the cathode, and the zinc the anode.
Therefor, when you have Al plus SS, the Al will corrode, and when you have Al plus Zinc, the zinc will corrode. While it sounds as if you would want the fastener, not the boat to corrode, you have to look at quantities. On a hull, you have hundreds, often thousands of pounds of aluminum, whereas the fasteners used to attach the deck and accessories would equate to just a few pounds. Thus, the stainless fasteners aren't going to have much of an effect on the large mass of aluminum, but the large mass of aluminum will have a major effect on the small amount of zinc.
This is precisely why zinc is used as a sacrificial anode on aluminum boats and outboards, as OEM parts. The zinc is used, as it will corrode first, and thus keeps the natural galvanic corrosion from seawater from attacking the boat. It will favor the anode over the cathode any day of the week and twice on Sunday.
The is NO way to stop all corrosion on aluminum with usual methods. In fact, aluminum would be a virtually useless material if it didn't corrode. Instead, it rapidly oxidizes (as in almost instantaneously), which is why it must be welded on AC current, as it needs the alternating current to break up the oxide layer. Thus, you have to limit the corrosion. Ideally, matching alloy aluminum fasteners would be used, but they aren't practical, from a strength standpoint. Gold and platinum aren't practical from a cost standpoint. Stainless steel is the most commonly accepted medium between cost and function, which is why it is a standard in the marine industry.
If you don't like the way the stainless and aluminum co-mingle, weld them together, with a compatible alloy filler material. It is the best way to ward off corrosion by dissimilar fasteners, as no mechanical fasteners would be used.
At the risk of sounding like I'm taking a shot back at you (it isn't intended that way, really). Go back to Bolt's Plus (NOT Boat's Plus #-o ), and ask them all about their experiences with aluminum boats. Then, come back, and ask all the members of this site, and if you wish, I can email you links to about 15 other sites, as well as around 50 individual people (real people) who live and breath aluminum boats, and you can get facts and observations (not opinions) as to the condition of various metals around aluminum boats. In the members of this site alone, you probably have a couple hundred different boats, where the owner was able to see the difference between zinc coated, and stainless steel bolts after years in service, in a variety of conditions. While working on paper is great, there is no substitute for real world experience, as anomalies do happen, which will favor a different outcome. This is why an engineer that has spent some time in the construction trade is *generally speaking* much better than one that never has done anything else.
Go to ANY trade in the world, be it carpentry, welding, engine repair, painting, cooking, etc, etc, and you'll find people doing stuff that doesn't work on paper, or isn't orthodox. However, it still yields acceptable results, and it is done because it works, and only experience could tell you this.
I'm not giving you any grief about your choice of fasteners for your boat. It's your boat, you did the research, and I'm sure you'll be happy with the results. However, I have to second what perchin said. If you don't want other peoples opinions, don't post on a message board. If you tell us something to be so, and I think it isn't, I'll give my opinion. I expect to be corrected when I'm wrong as well.
Go to ANY trade in the world, be it carpentry, welding, engine repair, painting, cooking, etc, etc, and you'll find people doing stuff that doesn't work on paper, or isn't orthodox. However, it still yields acceptable results, and it is done because it works, and only experience could tell you this.
I'm not giving you any grief about your choice of fasteners for your boat. It's your boat, you did the research, and I'm sure you'll be happy with the results. However, I have to second what perchin said. If you don't want other peoples opinions, don't post on a message board. If you tell us something to be so, and I think it isn't, I'll give my opinion. I expect to be corrected when I'm wrong as well.
jdrautoworks
Active member
bassboy1 said:
This is the correct answer corrosion due to electrolysis! To bad you can't get a good nickel plated fastener (very close to aluminum alloy) and chrome works ok also no as reactive as SS and if you cut through the chromium you will still have a layer of nickel and bronze but the cost is a bit high.
Truckmechanic
Well-known member
dyeguy1212 said:
No, didn't mean that it was better. Just that it would work.
wasilvers
Well-known member
Stainless steel for 13 years on one of my old aluminum boats. All was well with the aluminum - visually anyway - and I could still get the old bolts off. Had much worse issues with treated plywood being used and the aluminum being eaten away.
Zinc as sacrificial metals on the motor do it for me.
Just one guys opinion,
Will
Zinc as sacrificial metals on the motor do it for me.
Just one guys opinion,
Will
