Corrosion between stainless steel and aluminium?

[ShafferNY]

Is there a big problem with corrosion between these two metal?<br /><br />The reason I'm asking, is that I pulled the keel runners off my 12ft aluminum boat because they are TOTALLY shot. They wore completely through and some are crushed, they're so thin. <br /><br />I don't have a any experience welding aluminum, but I can weld stainless steel. I'm contemplating making my own runners from a piece of 3/32" x 3" x however long and welding a piece of angle iron(stainless steel) over it. <br /><br />Normally a boat this size doesn't stay in the water long enough to worry about corrosion, but in my case it stays in the water about 3-4 months out of the year. Freshwater not saltwater by the way. <br /><br />I would like to just buy new runners but I don't know who, if anybody sells them.<br /><br />Thanks,<br />Chris

 

[FlyBoyMark]

Re: Corrosion between stainless steel and aluminium?

Order them from the maufacturer, they will have to be drilled to match the existing holes, go to this link on the subject I wrote about some time ago.... web page <br />Or this one...<br /> web page

 

[ShafferNY]

Re: Corrosion between stainless steel and aluminium?

Hey thanks, I did a search earlier and came up with nothing, I knew I had posted this last year.

 

[ShafferNY]

Re: Corrosion between stainless steel and aluminium?

I did a quick search and came up with nothing. I'm going to talk to my brother about making one, he has access to a TIG welder I think. That would be the way to go. Then just attach it to the bottom of the boat. <br /><br />This boat has a single hull, and I read what you said about the S.S. TRUSS HEAD phillips screws. Are these something I'll keep tripping over?

 

[marty_scher]

Re: Corrosion between stainless steel and aluminium?

ShafferNY<br /><br />Yes, the two are a very corrosive combination.<br /><br />Electrolytes, in this case, water, make the corrosion much worse.<br /><br />Protective coatings will help, if you are not already using them.<br /><br />Good luck

 

[FlyBoyMark]

Re: Corrosion between stainless steel and aluminium?

If you use the 5200 as I described, you will not have any corrosion problems what so ever. In addition you should follow my instructiions for treating the areas where the screws go through.<br /><br />Here's the scoop....aluminum boat restoration is one of the things I do in the welding business;<br />1. Strip any paint if any.<br />2. Use nylon wheel in a 2500rpm drill to clean corrosion.<br />3. Use FINE S.S. wire wheel for heavy deposits.<br />4. Wash boat with soap and water and rinse well then let dry.<br />5. Us Alumiprep diluted about 3 to one and keep working all areas of the boat with a fine 3M pad (do not let this stuff dry on the boat). Then rinse with water and let dry.<br />6. Then apply Alodine full strength using a brush, keeping the aluminum wet and soak for about 3 minuts. Rinse and let dry.<br />7. Use aircraft or marine "green" zinc chromate primer, cut 40% with toluene. Paint entire boat.<br />(item 8 is if you're going to paint the entire hull)<br />8. Let cure for 5 days and paint whatever color you want....any good quality automotive paint or marine paint will do, use something that has a hardner added to it.<br />(do number 9 BEFORE you treat the aluminum)<br />9. Any corroded rivets can be replaced with #10-24 X 1/2" S.S. Phillips TRUSS HEAD screws and flat washer with nylon locking nut. use a drop of 5200 under the head of each screw. use a 3/16" drill bit to drill out the rivet Make sure you drill out the rivets and treat the boat as aformentioned BEFORE you put the screw in.

 

[FlyBoyMark]

Re: Corrosion between stainless steel and aluminium?

Whats the name of your boat manufacturer?

 

[ShafferNY]

Re: Corrosion between stainless steel and aluminium?

Duratech, from what I've heard the went out in the fifties. <br /><br />I don't want to do a full-on restoration the boat really isn't worth that, but I would like to get it fixed. I intend to use it as a second fishing boat. <br /><br />I'm getting my sister digital camera within the next few days, so hopefully I can post some pictures. <br /><br />I really appreciate all the help.

 

[FlyBoyMark]

Re: Corrosion between stainless steel and aluminium?

I think your boat manufacturer is gone by by....but get some cross section demensions compare to newer aluminum boats and you might be able to buy keels from them. Try several different brands of v-hulls....we'll wait for ya pics...

 

[Boatist]

Re: Corrosion between stainless steel and aluminium?

ShafferNY<br />As far as corrosion between Stainless Steel and Aluminum I do not think it is too bad. My Aluminum boat has Stainless Steel bow eye and stern eyes for towing. It is a 1980 boat and in 1981 I added Stainless Steel Bennett Trim Tab and have seen no corrosion at all. I do boat in salt water about 30 percent of the time but trailer boat at end of day. Also outboards lower units are Aluminum and drive shafts and prop shaft are Stainless. Make sure do not use anything copper.

 

[mrmargaritaville]

Re: Corrosion between stainless steel and aluminium?

any application where steel, even stainless steel is in contact with aluminum is bad, real bad. You have in effect created a battery by having stainless and aluminum in contact (and of course a battery is a very corrosive enviornment). The two metals must be isolated, and not kept in contact with each other.

 

[Lark40]

Re: Corrosion between stainless steel and aluminium?

I used to be a Duratech dealer. They were a successful business<br /><br />They were sold to PennYan in 1965.

 

[Karl Seibel]

Re: Corrosion between stainless steel and aluminium?

Hey Shaffer....take a small piece of stainless and a small piece of aluminum....tape them together and throw them in a bucket of water...u might then find out then what they do...make sure they are thin...like a aluminum can, so you get the results quick

 

[FlyBoyMark]

Re: Corrosion between stainless steel and aluminium?

Shaffer...You will have no corrosion problems...If you follow my instructions. I have multiple restorations from my welding and fabricating business over ten years now with NO corrosion. Most of them are bare hull boats with screws exposed. The only problem that could arise is in salt water full time in water dockage and you have eddy currents of electric leaking from a dock source or improperly grounded hull.