Rusted bolts & Steelflex

Should I take care of rusted areas before applying steelflex? I just finished up sanding the outside of the boat and saw that there are some bolts thoughout the hull that are rusted. I have some Rust Oleum Rust Reformer (supposedly turns the rust into a black paintable surface)... should I apply this to the rusted areas BEFORE i put steelflex on the hull?

You have rusty steel bolts in the aluminum hull? Will they be exposed (to the weather) on the inside of the boat? If so, they could continue to rust and possibly cause electrolysis between the dissimilar metals. Possible to replace them?

Waterwings said:

You have rusty steel bolts in the aluminum hull? Will they be exposed (to the weather) on the inside of the boat? If so, they could continue to rust and possibly cause electrolysis between the dissimilar metals. Possible to replace them?

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It looks like they were used to attach the benches on inside the boat. The head of the bolt & washer (both rusted) are underneath on the exterior hull. These bolts go thru the hull and attach the benchs to the interior. I can take a pic if needed. Not all of them are rusted, probably about half. Im not sure if its just the head or the entire bolt is rusted w/o taking them out.

I'm a little weary about replacing them (if that's what you're suggesting).... dont like messing w/ holes in the hull.... is this mandatory?

i would do your best to remove all of the rust you can with a wire wheel or brush. that will give you an idear of how deep the rust has gone, or if its just surface rust

i'd replace the bolts, its simple has cutting them off and screwing a nut on a new bolt w/ some sealant. not mandintory just depends on how long you plan on keeping the boat.

Probably not mandatory, but eventually, if the bolts are also rusting, it may wobble-out the holes due to corrosion and deterioration of the bolts and the seats might become loose. Just voicing my concerns, as it's hard to tell w/o pics. Post some pics if possible to get a wider selection of suggestions/advice from the members here.

Loggerhead Mike said:

i would do your best to remove all of the rust you can with a wire wheel or brush. that will give you an idear of how deep the rust has gone, or if its just surface rust

i'd replace the bolts, its simple has cutting them off and screwing a nut on a new bolt w/ some sealant. not mandintory just depends on how long you plan on keeping the boat.

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What sort of sealant should I get for this? I'll probably run over to home depot or menards tommorow....

Replace the bolts and fasteners with stainless hardware, and use 3M 5200 Marine sealant (available at Walmart). Let the sealant cure well before putting the boat in the water.

Here are some pics of the bolts throughout the hull. As you can tell...some of them are fine (no apparent rust) and some are covered.... should I replace all or just the ones that I see rust on? There is a chance I will be selling the boat next month to upgrade to another, either way id like it to be in the best possible shape. Just don't know if it would be overkill or not.

Here is the outside hull which has been sanded down to bare aluminum. The bolt pattern holds the bench down inside the boat.


This is a closeup of what some of the bolts look like.


Again, some don't look too bad


Here is the inside where the bench is. Again, some not so bad....


And some are pretty bad...


What's the verdict guys? Replace some, all, or leave it as is?????? Again, on the exterior I do plan on covering w/ Steelflex... on the inside i'm putting a low plywood floor down covered w/ either carpet for Durabak.

I've never seen hex head bolts through a hull like that. At the minimum I would replace all of them with stainless bolts sealed with 5200. Also, I would go back with carriage bolts or sleeve bolts that have rounded heads for the underside of the hull. The problem with leaving them is that the bolt and nuts on the inside will still be in contact with water and will corrode eventually leading to a leak, also the dissimilar metal in the water will lead to electrolysis and could damage the hull. Even stainless and Alu. together in a flow of water will lead to electrolysis, but you can isolate them. The best bet would be to put in Alu rivets for longevity. If you leave them I would put an sacrificial anode somewhere to alleviate some of the electrolysis.

Easier to do it now rather than later after the hull has pitting problems from electrolysis.

**** went to both Menards and Home Depot and neither carried the stainless steel bolts for the 3/4'' x 1/4''D I need (carriage or hex). Hopefully, Ace Hardware will come thru for me tommorow. If they don't... is there any good online retailers that would have them?

Also, went to Walmart and they didn't have the 3M 5200 Marine Sealant... is there a substitute?

Try a fastener place like western fasteners, I get my stainless hardwear from Lowes.

No substitute for 5200, iboats has it oinline, West Marine also carries it if you have one locally.

I would recomend aluminum rivets over bolts, they will probably be around 12 cents or so each, alot cheaper than stainless and will hold up better in my opinion. It only takes a couple of minutes to put the rivets in and it is back to the way it came from the factory. Good Luck....

Flintcreek...

Well I was able to find some 3M 5200 but had a question regarding it.... The package says it bonds/seals with Fiberglass and Wood... it doesn't say anything about aluminum. Are you sure this stuff will work with my aluminum boat? I know its the right stuff because the package reads "3M Marine Adhesive Sealant 5200" in a white tube.

Also, when putting this stuff on...how much should I apply to each area and where abouts? Directly on the thread or on the washers?

Put the 5200 between any thing metal, hull-seat flange, washers...everything. While it doesn't make a 100% bond to Alu like it will glass or wood, it is better than anything else and it will keep water out forever.

I just went through something similar to your problem. The right way to fix it is to replace those bolts with rivets. Trust me installing a rivet is just as easy as installing a bolt. I was leary at first too, but with the help and encouragement from the great folks on this site I got it done. The rivets I got from grainger at a little over $10.00 for a hundred. The originals were 5/32 but some were wallerd out so I drilled them all to 1/4 in. No sealant needed, just have a friend hold a piece of metal on the head side while you tap the other till it expands and tightens up. Just remove one bolt at a time and replace with a rivet, that simple. Very easy, you'll be surprised.
Me and a friend replaced every rivet in the entire boat in under 2 hrs. Then paint the steel flex on and you'll never have to worry about leaks,corrosion, or structural integrity.
once you put the steel flex on and those bolts rust out further a repair then is going to be a pain.Hate to see you do all this work and then have to do it again in a couple of years.

I have been reading along and I have heard about this steel flex on more then one thread. can you only get it off the internet? About what does it run? The trailer looks great, and you should definately go with rivets.