will black iron steel and aluminum together cause a problem?

[oldsubsailor]

Very new to fresh water boating. Just picked up (yesterday) a used 1987 28 foot Lowe pontoon which is need of some TLC. After I got the boat home, I was underneath it and noticed that the previous owner whom has replaced the deck and carpet, put new furniture on it and was generally in the final stages of getting this boat on the water, has put a heavy steel channel iron piece (approx 10 inches wide and 2 to 3 inches deep, looks like it would hold a elephant) across the pontoons just forward of the transom under where the batteries are installed inside of a bench couch for setting. I do not know why he put this in there, but I am concerned about the steel being screwed directly to aluminum. I thought I had read in this forum that you did not want to do that because the two dissimilar metals would cause corrosion. I would like to try to get this boat on the water with the grandkids in what little time we have left this season. We are in southern Oklahoma, so a couple more months, unless global warming kicks into high gear, then we will have all winter. But I am off subject here, so anyway I am thinking of leaving the metal in boat until this winter, then pull everything off deck, furniture, carpet back as far as I have to, and replace this steel with something more compatible like aluminum or maybe even strong wood crosspiece. Will the metals eat each other quickly or is this something I should not even worry about ever and go fish and swim?

 

[jbcurt00]

Yep, steel was bad choice for 'repair', it should be removed.

Also need to figure out why such a large beam was used, and fix that problem too.

 

[Scott Danforth]

a 10" c-channel is like 18# per foot. it will rust and be a mess.

I would need to know why the channel was put there, then I would fix it right.

 

[dingbat]

As long as there is paint on the channel, I wouldn't worrying about it rusting to bad in sweet water.

Steel and aluminum play pretty well together. Your biggest worry is iron oxide staining your toons if the paint is compromised.

 

[WaterDR]

This belongs in the "what was someone thinking" category.

You will get galvanic corrosion anytime two dissimilar metals are in contact with each other based on how far apart the two metals are on the galvanic scale.

Aluminum is a great metal for fresh water. It does not rust ever and it light. Steel is heavy and rusts.

IF the steel is completely covered 100% it will be fine. Something like POR 51 will make it last forever. However, if any part of the metal is compromised the small section will pit and fail rapidly because you just made a powerful anode.

 

[oldsubsailor]

The steel plate is unpainted, no gasket or any type of material between it and the aluminum. Bottom line, this winter, I take the back half off the boat and replace the steel plate and figure out why it is there. Could get ugly. Thank you for all of your responses.

 

[icwingman]

Very new to fresh water boating. Just picked up (yesterday) a used 1987 28 foot Lowe pontoon which is need of some TLC. After I got the boat home, I was underneath it and noticed that the previous owner whom has replaced the deck and carpet, put new furniture on it and was generally in the final stages of getting this boat on the water, has put a heavy steel channel iron piece (approx 10 inches wide and 2 to 3 inches deep, looks like it would hold a elephant) across the pontoons just forward of the transom under where the batteries are installed inside of a bench couch for setting. I do not know why he put this in there, but I am concerned about the steel being screwed directly to aluminum. I thought I had read in this forum that you did not want to do that because the two dissimilar metals would cause corrosion. I would like to try to get this boat on the water with the grandkids in what little time we have left this season. We are in southern Oklahoma, so a couple more months, unless global warming kicks into high gear, then we will have all winter. But I am off subject here, so anyway I am thinking of leaving the metal in boat until this winter, then pull everything off deck, furniture, carpet back as far as I have to, and replace this steel with something more compatible like aluminum or maybe even strong wood crosspiece. Will the metals eat each other quickly or is this something I should not even worry about ever and go fish and swim?

U will galvanic corridor the dissimilar metals go to scrap yard n get aluminum

 

[GA_Boater]

Old thread!

Closed.